oticthree shear moduli: the in-plane shear modulus g12, and two transverse moduli g13 and g2 3....

85
I I I I I I I I I ·J 0 00 l-4 Q q: LR 29763 November 30, 198t TRANSVERSE SHEAR STIFFNESS Of T300/5208 :h'lc· . ' GRAPHITE-EPOXY IN SIMPLE BENDING By : F. E. Sandor![. Staff Engineer Structures & Materials Laboratory OTIC SEP 3 1982 S ELECTED D Company A Division of Lockheed Corporation Burbank, California 91520 DISTRIBUTION STATEMENT A Approved for public releo.set Distribution Unlimited 82 U9 03 07 6

Upload: others

Post on 05-Jul-2020

2 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I I I I

I I I I I ·J

~ 0 ~ 00 ~

l-4 ~ Q q:

LR 29763 November 30, 198t

TRANSVERSE SHEAR STIFFNESS Of T300/5208 :h'lc· •

. ' GRAPHITE-EPOXY IN SIMPLE BENDING

By : F. E. Sandor![. Staff Engineer Structures & Materials Laboratory

OTIC SEP 3 1982 ~ SELECTED

D

~Lockheed-Califomia Company A Division of Lockheed Corporation Burbank, California 91520

DISTRIBUTION STATEMENT A

Approved for public releo.set Distribution Unlimited

82 U9 03 07 6

Page 2: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I LR 29763November 30,1981

TRANSVERSE SHEAR STIFFNESS OF T300/5208

GRAPHITE-EPOXY IN SIMPLE BENDING

By: P.E. Sandorff, Staff EngineerI Structures & Materials Laboratory

I Accession For*-iNTTS GRA&IDTIC TAB [IUnannounced LJ 2

Ava-ilability CodesjAvail and/or

Dist Special

waaLockheed-.California CompanyA Division of Lockheed CorporationBurbank, California 91520

DISTRIBUTION STATEMENT AApproved for public releasel

Distribution Unlimited-

Page 3: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LOCKHEED • CALIFORNIA COMPANYA DIVISION OF LOCKHEED AIRCRAFT CORPORATION

Ir -

I REPORT NO. LR 29763

DATE _November 30, 1981

MODEL ID

TITLE COPY NO. __

jTRANSVERSE SHEAR STIFFNESS OF T300/5208

L GRAPHITE-EPOXY IN SIMPLE BENDING

IREFERENCE 41-5707-3040

CONTRACT NUMBER(S)

i

PREPARED BY_P. E. Sandorff, Staff EngineerStructures Laboratory

I APPROVED BY \'V- 7 "iW. F. Dryden, Department Engineer

Structures & 4aterials Laboratory

APPROVED BY -

? Fairchild, Division Engineer

I. ggineering Laboratories

II

The information disclosed herein was originated by and is the property of the Lockheed Aircraft Corporation,

I and except for uses expressly granted to the United States Government, Lockheed reserves all patent,

proprietary, design, use, sole, manufacturing and reproduction rights thereto. Information contained in this

Ireport must not be used for sales promotion or advertising purposes.

REVISIONSREV. NO. DATE REV. 9 PAGES AFFECTED REMARKS

FORM 402-2

Page 4: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I LR 29763

!!

FOREWORD!

This report describes work accomplished during 1980 and 1981 in the program,

Experimental Mechanics. This program is funded by the Lockheed Independent

Research and Development Program, and administered by the Structures and

Materials Laboratory.

Acknowledgement is due K. N. Lauraitis and J. T. Ryder for their helpful

discussions, and to R. C. Young, F. L. Imera, R. LaForce and F. M. Pickel for

special care in specimen fabrication and testing.

I!

'WLockheed-CaMfOMA Company i

Page 5: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

FOREWORD

ABSTRACT

INTRODUCTION

OBJECTIVE

APPROACH

SPECIMENS

EXPERIMENTAL PROCEDURE

Axial Tests

Flexure Tests

TEST RESULTS AND ANALYSIS

Axial Tests

Flexure Tests

TABLE OF CONTENTS

Approximate Method for Shear Calculations

Overall

CONCLUSIONS

REFERENCES

APPENDIX

"WLockheed -Csllfom/a Company

v

iii

vii

1

4

5

9

11

11

11

14

14

17

29

33

35

36

39

LR 29763

Page 6: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I

ILR 29763

S

I ABSTRACT

I.Buckling and crippling of a structural element is governed by its elastic

Jproperties. Nevertheless, a complete definition of the elastic constants of agraphite/epoxy laminate, including the transverse shear moduli (important

under high compressive stress), has never been accomplished. For this pur-

pose, tension, compression, and bending tests were conducted on square-section

specimens cut 0-degrees and 90-degrees to the fiber axis from 64-ply unidirec-

tional T300/5208 laminate. Axial test specimens were instrumented with tee

gages to obtain data on extensioral moduli and Poisson's ratios. Bending

J deflections were measured with high p-ecision and analyzed using a rigorous

finite difference solution for stress distribution to derive the shear moduli

Ialong with the extensional moduli acting in bending. Redundant determinations

were obtained for the nine elastic constants of Hooke's law as generalized for

specially orthotropic materisl.

Extensional moduli obtained under axial load and in bending agreed with each

other to within one percent. A self-consistent set of properties was deter-

mined which were generally in accordance with published data, and which

f established the material as being transvers. y isotropie and conforming to the

linear theory of elasticity.. The value obtained for the shear modulus G12

(=G13) was 4500 MPa (0.65 Msi), some twenty percent lower than that generallyaccepted on the basis of 4450 tension test data. The value of the transverse

shear modulus G23 was 3650 MPa (0.53 Msi), in accordance with published re-

sults of ultrasonic tests.I

nkLockhteed-CamY1Mw CoMaWY

vii

Page 7: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I

1 LR 29763

II INTRODUCTION

In the design and analysis of metal aircraft structures which buckle under

compressive loads, and those which deform under transverse bending load. it is

seldom necessary to consider the effects of shearing deformation. The trans-

verse shear stiffness of graphite-epoxy composite laminate, however, is no

more than a fifth that of aluminum alloy, and the adverse effects of shearing

I defcrmation will require consideration in many practical applications of

advanced design. Reference 1, for example, indicates a reduction in com-

pressive buckling stress of fifty percent for stiffener elements designed for

high stress (width to thickness ratio of 10). An evaluation of the transverse

T shear modulus of this material to a reasonably high confidence level is there-fore necessary for applying it efficiently in aircraft construction.

IThe elastic properties of composite laminate are usually represented as

specially orthotropic. In this analytic model, unidirectional laminate has

J three shear moduli: the in-plane shear modulus G1 2 , and two transverse moduli

G13 and G2 3 . There are several direct, relatively simple test methods for

I evaluating G12, but very few for the transverse moduli. A selected biblio-

graphy is presented in References 2 through 15.

The most commonly used method for evaluating the in-plane shear modulus of

composite laminate is the + 450 tensile test (Reference 5). In this test, a

Utee or rosette strain gage provides bi-directional stress-strain data; two-

dimensional transformation of stresses and strains identifies shear stress vs.

shear strain in the plane of the laminate. While this test is concerned only

with response in the plane of the laminate, the material is usually assumed to

be transversely isotropic on the basis of its structure, in which case 013

=G 12. Investigations have demonstrated this method to be equivalent (probably

to the limitations of experimental control) to the cross-sandwich beam, thin

'SkLockheed-Califforna Comping"

-vJ

Page 8: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

tube In torsion, ten-deg off axis, panel shear, and rail shear tests (Refer-

ences 3, 6, 8). Tests of T300/5208 graphite/epoxy of 0.62-0.67 fiber volume

fraction by the +J45 ° tension method have indicated G - 0.T4 - 0.80 Msi- 12 2

(References 9.18). This value is generally understood to be the initial slope

of the stress-strain relation. A possibly significant aspect of all the test

methods in this category is that they usually furnish decidedly non-linear

shear stress-strain curves (for example, see References 3, 6, 8, 9, and 16).

The complete set of material elastic constants can be evaluated from the speed

of acoustic wave propagation in ultrasonic tests of specimens of special

geometries. Such experiments indicate G12 and G13 to be about thirty percent

higher than obtained with the + 450 static tension test; Reference 7, for

example, gives 1.03 Mai for this property, with G23 0.527 Hal. Engineers

hesitate to use such values in design because a one-to-one relationship

between microscopic dynamic oscillations and macroscopic static deformation

has not been demonstrated for graphite-epoxy; indeed, even in isotropic

metals, the two techniques usually provide slightly different results.

Since one of the engineering uses of the shear modulus is to improve the

analytic prediction of buckling phenomena, a practical approach is to test

simple buckling specimens, determine the reductions in critical load due to

shear effects, and back-figure to derive applicable values of the shear

moduli. This method was used to analyze some 1800 column test data in

Reference 9. For T300/5208 laminate, this approach indicated room temperature

values of G13 = 0.30 Msi and G23 = 0.045 Hsi. Besides being unexpectedly low,

these values conflict with the assumption of transverse isotropy.

In the past few years the Air Force Materials Laboratory has developed a

direct test method for evaluating two of the shear moduli. This method

utilizes a half-inch diameter, six-inch long cyclinder cut 90 degrees to the

fiber direction from thick unidirectional laminate. Shear strain gages are

mounted on the surface at 0 degrees and 90 degrees to the fiber and the

cylinder is loaded in torsion (Reference X). Tests of T300/5208 of fiber

volume fraction 0.63 reported in Reference 0 3 ive values of 0.866 and 0.506

Msi for G12 and G2 3P respectively.

W.)Lockheed 2-California Compay

Page 9: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I -

LR 29763

I Deserving of mention for its simplicity and low cost, a method known as the

Iosipescu shear test has recently been applied to composite laminates

(Reference 15). This test uses a specimen only slightly larger and harder to

fabricate than that for the ASTM D 2344 short beam shear test, and it makes

material characterization possible for both shear stiffness and strength in

all three planes. The method must be confirmed by test results obtained under

loading conditions realistic for structural applications, since (as with most

methods) the geometry is unusual and the purity of the stress condition might

f be questioned.

A method that is appealing from a practical standpoint determines the shear

stiffness from simple flexure tests in accordance with accepted handbook-type

formulas for bending and shear deflection (References 10 and 14). Application

of this method in Reference 10 indicated G13 of 16-ply T300/5208 laminate to

be 0.40 Msi. This method suffers from the crudeness of the handbook approxi-

mation made for shear deflection, as well as from the difficulty of achieving

adequate experimental precision.

The basis for an accurate analysis of flexure test data was established, in

Reference 19, by the development of a computer-aided solution for the plane

stress representation of a simple 3-point beam of orthotropic material. This

solution provides a precise determination of the complete normal and shear

stress distribution, and so permits accurate prediction of the bending and the

shearing components of elastic deflection. This predictive calculation can be

applied to determine the values of the elastic moduli which best fit redundant

sets of deflection data obtained in flexure tests at different spans. The in-

vestigation described in this report was planned to make use of this approach,

in order to evaluate the elastic constants of graphite/epoxy laminate under

loading conditions representative of typical structural applications.

II

'-q&-LOCkheed3-California Company

Page 10: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

OBJECTIVE

The express purpose of this investigation was to evaluate the transverseshearing stiffness of T300/5208 unidirectional laminate when subjected to

simple bending.

In the completion of this objective, answers to the following additional

questions were also sought:

o Which if any of the existing test methods for shear modulus

could be confirmed.

o What causes the disagreement among values obtained by different

test methods.

o Can the material be considered transversely isotropic or not.

o Is more fundamental study required on the nature of the material

and the elastic model used to represent its response.

",'Lockheed-CeinrU Co wi 4

Page 11: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

ILR 29763I

APPROACH

IFour elastic moduli govern the plane stress or plane strain response of

orthotropic material. In the x-z plane these are the two extensional moduli

Exx and Ezz, the transverse shear modulus Gxz, and the Poisson's ratio Vxz.

1 The bending stiffness of a flexure specimen is a strong function of Exx, a

weak function of Gxz, and almost independent of Ezz and vxz" Therefore, two

flexure tests obtained on the same beam at different spans provide sufficient

information to evaluate Exx and Gxz to good precision. To do this, however,

it is necessary to relate observed deflections to the moduli through an

accurate representation of the stress distribution.

The two-dimensional stress distribution for an orthotropic beam can be solved

quickly and to any desired degree of accuracy by the computer-aided relaxation19

technique described in Reference ,. This is a rigorous finite difference

analysis which derives values of the stress function over a matrix of interior

points to suit a specified set of boundary conditions. Once the stress

function matrix is determined, stresses are readily computed, and the strains

and deflections follow upon selection of the moduli.

The investigation was planned to take advantage of conventional axial load

* tests to identify the extensional moduli and the Poisson's ratios of a sample

unidirectional laminate. Identical square section specimens cut at 0 degrees

j and 90 degrees to the fiber axis from 64-ply graphite-epoxy were used for all

tests. A number were tested under axial load; these were instrumented with

strain gages. Replicate specimens were tested in three-point bending, the

stiffness being determined by measurement of central deflection. Each bending

specimen provided data in two planes of loading under identical test

I conditions. The unreduced test data therefore furnished qualitative

information regarding transverse isotropy and the relative magnitudes of G13

and G2 3. The experimental approach is illustrated schematically in Figure 1.

-" Lockheed 5-COMM&Company

Page 12: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

0 1 2

2 3 2

3::00, I-mer 900, 2-Oir 900, 301ir

El1 .~ E33V23, V21, V3 l ~ l E3& P13 E2,P1(Plans strain? (Pane strss) (Pu. iirum) (Plane stru)

.3 4

22 1

900, 3-Dir goo, 1-DIr 00, 3-Dir 00, 2-Dir

E22, G23 E22.G 1 2 E11,613 Ell,6G12

Figure 1. -Test Plan Schemoatic

nq.Lockheed-Caliorni Company

Page 13: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I

I LR 29763

IDeflection measurements made in the flexure tests included deformation

occurring in the test fixture and Hertzian-like bearing deformation of the

surface of the beam specimen. These effects comprised an error that was

J significant for tests at very short span. To provide correctional data,

supplementary tests were conducted on specimens loaded as a block in bearing,

and on the test fixture with the specimen removed. The correction for bearing

deformation was derived from the block-bearing test data with the aid of two

additional computer-aided relaxation analyses, by which the Hertzian

deformation occurring in the block specimen was related to that occurring in

the beam.

Reduction of the flexure test data was achieved by applying the analysis for

beam deflection to each test span and condition, using a trial-and-correction

procedure to obtain values of the moduli which best fit the multiple test

points. The procedure is illustrated by the the flow chart of Figure 2.

7

Page 14: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

.LR 29763

AXIAL FEUEFIXTUREBARNLOAD TESTS DEFLECTION DEFLECTICNTESTS TESTS TESTS

BEARIN RATE AT

OVERALL BFFL, RATEVS. SPAN H .ER.TZI ANALYSES

BRG, IDR.., RATESURF. TO SURF.

VS. BRG. LENGTH

1 ,LENGTH

FLXLAX' __________________

PRELIM..qILSSIANAVLYSES

, BRG, DEFt. RATE ]

SURF. TO MIDPLANE

ANALYSESh9

Figure 2 - Flow Chart, Test and Analysis Procedure

"rLockheed 8-&fr bCOPM

Page 15: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

SPECIMENS

To furnish stock for test specimens, a 64-ply unidirectional panel was

fabricated of T300/5208 low-resin content (35 %) prepreg tape. The layup with

symmetrical bleeder plies was placed under vacuum in a press for the standard

cure cycle (45 minutes at 1329C followed by 2 hours at 1790C); no post-cure

was applied.

To remove resin-rich surface material, a grinding operation using water

coolant was performed on both surfaces of the panel. Square specimens of

ten-inch length were then cut 0 degrees and 90 degrees to the laminate axis.

Final grinding reduced all sections to a uniform 10.59 x 10.59 mm (0.269 x

0.269 inch). Section dimensions were measured to ;0.0001 inch at stations

spaced every inch along the length.

Photomicrography of two specimens after test showed a high degree of

homogeneity, although traces of the ply boundaries indicated irregular

distortions from the plane. Photomicrographs are presented in the Appendix.

Resin analysis performed per ASTM D3171 on samples taken from the finished

specimens indicated a laminate specific gravity of 1.61 and a fiber volume

fractic;, of 68.6 percent. The specimens were dried at 66 °C (150°F) in vacuo

for two months prior to test, a procedure estimated to reduce the moisture

content to less than 0.1 percent.

Three specimens of each orientation were used for axial tests to obtain

extensional properties at 0 degrees and 90 degrees to the fiber direction.

The problem of applying test load in the thickness (3) direction was met by

cutting short lengths from specimens tested under axial load and reassembling

the short sections by adhesive bonding to form 3-tier and 5-tier compression

specimens.

vW,?Lockheed 9

-Californ/a CoevpanW

- -.--

Page 16: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

Additionally, to obtain specimens for axial load in the 3-direction which

were geometrically similar to the others, cubical elements were cut from a

fourth 90-degree specimen, reoriented through 90 degrees, and bond-assembled

as indicated in Figure 1. These assembled specimens were intended for test

under axial tension, but bond failure prevented tension loading of useful

magnitude. One of these specimens, which incorporated seventeen cubicalelements, was salvaged for axial compression testing by squaring the ends.

Three additional specimens each, of 00 and 900 orientation, were selected for

flexure tests. When supported for beam tests the central load was always

applied at the specimen midstation, with excess specimen length extending

symmetrically beyond the beam supports. Maxiumum variation in measured

section dimensions over the test span for any of these specimens was less than

0.3 percent.

"r LockPheed-CafltWe O 10

Page 17: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I LR 29763

IEXPERIMENTAL PROCEDUREI

j Axial Tests

Axial test specimens were instrumented with tee foil gages centrally mounted

on all four faces and tested in a universal testing machine. Gage output vs.

load data were automatically recorded and reduced with the Rye Canyon

j centralized digital data acquisition system, which has a demonstrated overall

accuracy better than 0.05% of selected range. Tension loading not exceeding

0.003 strain was first applied using Templin-type mechanical grips. The

specimens were then reduced to approximately 10 cm (4 inch) length, the endsI squared, and compression loads applied between flat, adjustable platens. In

compression tests of built-up specimens in the thickness (3) direction, the

element bearing the gages was always the central member of a stack of

identical and identically oriented elements, in order to minimize end effects.

j Representative stress-strain curves obtained in these tests are presented in

the Appendix.

Flexural Tests

Flexural tests were conducted in the special fixture shown in Figure 3. Load

was applied and reacted through hard steel surfaces of 3.175 mm (0.125 inch)

radius. The width of the loading nose matched that of the specimen.

Deflection was measured between the loading nose and the fixture base with aoclip gage (MTS 632.02B01). The Rye Canyon centralized digital data system was

used to acquire, record, and reduce load-deflee ion data. End-to-end

calibration of the deflection measurement and recording system against a

certified Templin extensometer calibrator indicated overall accuracy and

Ilinearity of + 1.3 micrometer (0.00005 inch) maximum deviation over a range of2.5 mm (0.10 inch).

" aLockheed n-CalifoMia Conmpufy

40, hi's

Page 18: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

00

7,j

ockheed 1-camfrnie ompan

Page 19: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

Tests were conducted at eight different spans on each specimen, providing

replicate data from three specimens for each of the four beam orientations.

Test span lengths had to be short enough so that shear deformation was large

compared with the expected error in measurement, yet not so short that the

I error caused by local bearing deformation became intolerable. Maximum applied

loading corresponded to a beam theory strain Mc/EI of about 0.004.

I Representative deflection vs. load curves obtained in these tests are

reproduced in the Appendix. Except for initial softness, which may be

attributed to bearing on asperities and possibly to slight accomodation in

torsion, load-deflection relations were quite linear.

I The measured load vs. deflection included load carried by the clip gage as

well as that on the test specimen. A test was conducted on the clip gage

j alone, measuring deflection with a dial gage, to evaluate this quantity. The

results, which are included in the Appendix, provide a correction which was

important for the longest test spans.

A supplementary test was performed to evaluate the error introduced into the

flexure test data by deformations which occurred in components of the test

fixture included between the gage points. For this test the loading nose was

brought into contact with the base of the fixture, and the load-deflection

characteristics recorded as before. The resulting curve is reproduced in the

Appendix. (These measurements provided only an approximation to the behavior

in the flexure test because some deformation occurred in the base under the3 loading nose instead of at the beam supports).

Tests were also conducted with load applied to representative specimens as in

the flexure tests but with the specimens resting directly on the flat base of

the test fixture, in order measure specimen bearing deformation. Deflection

vs. load curves obtained in these tests are included in the Appendix.

" ,Lockheed 13

-CaIRONI Compay

Page 20: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

TEST RESULTS AND ANALYSIS

Axial Tests

Compliance data under axial stress were derived by manually evaluating the

slopes of the stress-strain curves furnished by the data processing system.

This is an operation that produces repeatable values within one half to one

percent if the slopes are truly linear. Linearity existed over the maJor

portion of the curve for all tests except those for tension in the fiber

direction, in which stiffness increased slightly with load. In these cases

secant data were obtained over several ranges.

Corrections for strain gage transverse sensitivity were applied after

evaluation of the slopes. Tabulations of the material compliance

coefficients, obtained by averaging data from back-to-back strain gages, are

recorded in the Appendix. Mean values and coefficients of variation are

presented in Table 1.

With only moderate exception, these data are self-consistent and fit the

usually assumed model which displays symmetric coupling effects (S12 2 S21,

$13 = S3 1' $23 = $32) and transverse isotropy (S22 = S33 S12 = S13). A set

of coefficients for this model, obtained by averaging all determinations

bearing on any particular value, is as follows (units of Ue/MPa (ue/psi)):

6.92 (0.048) - 2.2 (0.015) - 2.2 (0.015)

= -2.2 (0.015) 94 (0.65) - 46 (0.32)

i,j = 1,2,3 -2.2 (0.015) - 46 (0.32) 94 (0.65)

Corresponding values of the engineeering constants are listed in Table 2.

Caotww C p& 14

Page 21: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

- - ~ -- - - LR 29763

.a4 . . . . It

-% 4 00.O

44 0% Go4 %

H-l 4 -4 -44 .4 r C 4

cj ~In In

F4 -40% 0%

lm ,m11g 9 C C -4 V-4

E I.

-A1 In I

I..00 C4 (C4 -.

443 H .14 U-

0 w d~

0 0 ;r -t 0Go

0 -4 -4 ( ~ U

89 00O

00

4. -4 C4 4 .e

1000

0 0010-

IMnL"o

0 14

.co0i Ic U.-.

Page 22: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

21LR 29763

I

TABLE 2 RESULTS OF AXIAL LOAD TESTS

Coef

n Value Var'n

%

Extensional Moduli:

Ell 14 21.0 Hsi 2.1

E22, E33 27 1.54 Msi 2.9

Poisson's Ratios:

v12, V13 14 [ 0.31 3.8

V2 3 , V32 13 0.49 7.3

v21' v3 1 (V 12E22/E11) 13 0.023 8.8

I

N5LWckheed 16

Page 23: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I

Flexure Tests

Recorded test results were provided by computer in the form of load-deflection

curves, which were analyzed manually to obtain values of slope. The resultant

deflection rate data (pin./lb) and the corresponding range of loading over

which the behavior was essentially linear are listed in Table 3.

The correctional data also were reduced to terms of deflection rate. The

correction for clip gage load was incorporated by combining it with the

average deflection rate obtained from the three specimens tested under each of

the thirty-two test conditions. These results are included in Table 3.

Bearing deformation effects were non-linear in nature, and reduction of the

data produced the deflection rate vs. load relations presented in Figure 4. A

preliminary analysis of the flexure test data was required before the

correction for bearing deformation could be applied.

The finite difference relaxation technique of Reference 19, which was used in

analyzing the flexure test data, is based on the stress function relation for

orthotropic material:

a4 04+2 + K 24 -0

z ax4 ax22 X O 4inaxaz2 x z4

Here, for plane strain, 2( E- 2y/E )K -Y x y (2)

x E XX/2G XZ-v X -v ,Y v Z E YY/E (2)x x/2x xz y Vx~ y ]zi

E (1 - v 2- YEz ) (3)

K - K XX z y /E ZZ2 X E (1 - v 2

zz xy Eyy/EXX)

Plane stress is expressed by placing E =0.

C& 1COMPWY 17

Page 24: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

Li 29763

ItI

.. .. .. .. .. ? . .. .

4+ .I... . . . . . . .

* t-4+ III I

,77400 7 C......*,

.......4 o ... .... . 00o0

, ,..O O C 0, 4 00 0 C ....C ,

f- .I~. .. 0 . . ... .. . i.0 0 .

ooo .4-. 0C O Co .wn

. . . .. ... ~ I. I I..... .. .. ., " . .

Page 25: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

1 14I -

12 >

I 0

>0

' !08 goo, -DIR

0 - Ni RN

2 0 00O -V ,2 OR 3 DIR.

I 6 'N BEM-

I4900v 1 DIR.KBLOC'( IN ARN

2I0 FIXTURE ALONE

S0 I I I I I I I0 40 80 120 160 200

j LOAD P(LB)

Figure 4 - Experimental Deflection Rates (Slopesof Recorded Load - Deflection Curves)

" ,Loclkheed 19-California COMOan

Page 26: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

The stress function solution was applied to treat the central portion of the

test specimen out to a distance 2h (twice the beam depth) from the point of

load application. Deflection of the remainder of the span was calculated by

beam theory. The net of point values was spaced h/1O in the spanwise (x)

direction and h/20 in the depth (z) direction. The model is shown

schematically in Figure 5. Preliminary studies showed that this analysis

provided the desired precision in deflection calculation.

Preliminary solutions of the stress function matrix were derived for each of

the flexure test conditions, using elastic constants determined in the axial

tests and assuming values of the shear moduli. The case of beam load in the

2-3 plane (obtained in the 90-degree beam with fibers oriented transverse to

the load) was analyzed as plane strain, the others as plane stress. Best-fit

values of E and G were then derived by placing

(dw test/dP) = a (dwb /dP) i + b(dw s/dP) (4)

Here dwb /dP and dw s/dP are deflection rates attributable to bending stress and

to shearing stress, respectively, calculated at the beam midplane; a and b

are error factors. Defining, for simplification,

dws /dP dw test IdP

x dWb/dP ;Y - db/dP (5)

Then

Yi = a + bxi (6)

and a and b may be derived by linear regression of y on x. If bending and

shear deformation are assumed to occur independently of each other, a and b

become correction factors for the moduli Exx and G xz. The error in this

asssumption becomes negligible if the correction is small, making iterative

improvement of the relaxation solution a practical measure.

IVLockheed-Ca/ft t/ Coman 20

Page 27: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

x .0x N

ILU CX

- CL

0 40 C4 -*

+ + 0I.n .

ciN a. I.

01 ,

L'U

101lq,?Lckh-4

.C911frnia olwan

Page 28: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

Correction of the flexure test data was then made for bearing deformations

occurring between the surface at which load was applied and the midplane of

the beam. Analysis was required to derive this correction quantity from

measurements taken surface-to-surface on a block which carried no bending

stress. General solutions for the two cases (viz., block in bearing supported

at the opposite surface, and section of a beam supported by moment and shear

at the ends) were obtained by extensions of the stress function relaxation

analysis described above which used closer grid spacing. For each of the

flexure test conditions, a set of specific solutions for deformation under the

two support conditions was derived for a range of values of the width over

which the central load was distributed. The block-bearing test data could

then be used to evaluate a load distribution parameter for each condition. By

assuming this parameter applied also to the beam-supported bearing problem,the applicable solution was identified and the bearing deformation occurring

between the loading nose and the beam midplane was evaluated.

This analytic procedure is considered only an approximation, which is

especially limited for short spans and high loads, but adequate as a

correction procedure. To facilitate the correction process, the analytic

solutions are arranged in nomographic fashion in Figure 6. Entry to the lower

set of curves with the block-bearing deflection rate, obtained from Figure 4

at the median of the load range of interest, lead via the upper curves to the

surface-to-midplane deflection rate in the flexure test. Data derived by this

method for the loading station, and (under half the beam load) for the support

station, were applied to correct the flexure data in Table 3. Also included

in Table 3 are corrections for deflection occurring in the fixture, taken from

Figure 4.

With the flexure test data refined, additional iterations of the solution for

Exx and Gxz were performed until best-fit values to the eight test points of

each set were obtained. Variation in the Poisson's ratios from the values

determined in the extensional tests was not investigated, other than to

SN Lockheed 22-Cao ~ Company

Page 29: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

f Ii LR 29763,5

| A

Som under bearing oedCL 3 (HTZLAX' solution)

EQ

IE C

iti

2 2-or

O 90 , -dir -d

~3 2

engthock under bearing load

Si . on cERTZ solutie a)2

002

0C 6 -Or -i

"0Lo-----

4* "dir

I 90w, I-dir

0 .01 .02 .03.0.0.0.7.8

Lengt under uniform bearing Wstre, Ip tin)

Figure 6. -Nomograph for Converting Block Bearing Deflection Data toSurface-to-Midplane Bearing Deflection of Beam

23

-io~Lockheed-Ca/?twT7A Con man

Page 30: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

demonstrate the effect to be too small to utilize. The results, which provide

at least one and in some cases two determinations of the extensional and the

shear moduli, are presented in Table 4 and summarized in Table 5. Extensional

and shear moduli derived from beams of different fiber orientation are seen to

be in good agreement, and agreement of the two transverse shear moduli G12 and

G13 (from 00 and 900 beams, respectively) again confirms the material as being

transversely isotropic. Furthermore, tie transverse shear modulus G23 is in

almost exact agreement with the value Wxpected by transverse isotropy, namely,

G23 = E22 /2(1+ v 23) or .52 Msi.

The fit to the test data achieved by iterative refinement of the relaxation

solution is indicated in Figure 7. While this plot demonstrates that the

computation provides an exceptionally good representation of total beam

deflection, it is misleading with regard to the precision of the shear modulus

determination. This process is better characterized by the plot of final

values of the deflection rate ratios presented in Figure 8.

IWrLoCkheed-CVmNCHpy 24

Page 31: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

--

--

--

-.-

:---

-->

..

.~~

...---

--.

,...

---.

~ ~ ~

-

n~

TABL

E 4

. A

NA

LY

SIS

OF

FLE

XURE

DAT

A

II T

est

Res

ul1

s

Rela

xati

on

S

olu

tio

ns

Best

Fi

t An

aly

si

s

Bea

m O

rien

t.

Dep

th

Wid

th

Sp

an

w'<

tst)

A

ssu

mp

tio

ns

·::'

b w

's

w'<

to

t>

X

< i

>

Y<

i>

0-

de

<J,3

-d

ir

0.2

69

5

0.2

69

1

1.0

20

8 1

.24

6

.81

8

.0

5.5

13

5

6.4

76

7 0

-deq

, 3

-d

i 1·

0.2

69

5

0.2

69

1

1.5

20

1

7

Pla

ne

Str

ess

6.0

0

10

.79

16

.8

1. 7

98

6

2.8

33

0

1"=0

.99

99

I O

-d

e<J,

3-d

ir

0.2

69

5

0.2

69

1

2.0

24

3

1 E

xx

=2

1.2

M

si

15.9

1

14

.80

30

.7

0.9

30

6

1. 9

48

7

a=

0.9

97

3 0

-de

<J,

3-

di

r 0

.26

95

0

.26

91

2

.52

0 50

.5

Ezz=

1.5

5

Msi

3

2.2

4

13

.74

51

.0

0.5

81

2

1 • '

56

65

b

=0

.99

65

O-

de<J

,3-

di

r 0

.26

95

0

.26

91

3

.02

0

78

.6

Gx

z=0

.65

Msi

57

.28

2

2 .•

71

80

.0

0.3

96

4 1

• 37

21

E1

1=

21

.26

O-

de

<J,3

-d

lr

0.2

69

5

0.

26

91

4.0

20

16

8 V

xz=

0.3

1

13

9.8

8

30

.69

1

70

.6

0.2

19

4

1 • 2

01

0 6

13

=0

.65

2

0-

de<

J,3

-di

r 0

.26

95

0

.26

91

5

.01

7

31

1

27

6.4

8

38

.64

31

5.

1 0

.13

98

1

.12

49

0

-de

<J,

3-

di

r 0

. 26

95

0

.26

91

6

.00

5

52

3 47

6.0

3

46

.44

52

2.5

0

.09

76

1

.09

87

O-d

e<J

,2-d

ir

0.:

:!6

91

0

.26

9j

1 .0

20

8

1 .2

4

.s.8

1 !3

.1

5.4

85

0 6

.4

43

8 O

-d

e<J

,2-

di

r 0

.26

91

0

.26

95

1

.52

0 1

8

Pla

ne

Str

es

s 6

.04

10

.79

16

.8

1. 7

85

2

2. 9

77

7

r=0

.99

91

O-d

e<J

,2-d

ir

0.2

691

0

.26

95

2

.02

4

31

Ex

x=

21

.1

Hsi

1

6.0

3

14

.80

3

0.7

0

.93

06

1. 9

48

7

a=

1.0

06

8 O

-d

e<J

,2-

dir

0

.26

91

0

.26

95

2

.52

0 5

0.5

E

zz=

1.5

5

Hs

i 3

2.4

6

18

.73

51

.2

0.5

77

1

1 .5

55

7

b=

1.0

01

0 0

-d

e<J

, 2-

d i 1

· 0

.26

91

0

.~695

3.0

20

' 78

.4

Gx

z=0

.65

H

si

57

.67

2

2.7

1 8

0.4

0

.39

37

1

. 35

94

E 1

1 =

2(:>

. 96

0-

de

9,

2-

d i 1

· 0

.26

91

0.2

69

5

'1.0

20

16

8

Vx

z=>

.3

1 1

40

.90

3

0.6

9 1

71

.6

0.2

17

8 1

.19

24

6

12

=0

.64

9

0-d

e<J

, 2-

d i 1

· 0

.2

69

1 0

.269

5

5.0

17

31

1 2

78

.42

3

8.6

4

31

7.

1 0

.1

31:1

8 1

.11

70

O

-d

eg

,2-d

ir

0.

26

91

0.2

69

5

6.0

05

5

25

4

79

.76

4

6.4

4

526

.2

0.0

96

8

1 .0

94

3

'.10-d

eg

,3

-d

ir

0.2

69

5

0.2

69

2

1.0

20

3

9.

0 P

lan

e

Strain

29

.30

9

.45

:59

.1

0.3

22

7

1 • 3

31

3

~

90

-de

<J,

3-

dir

0

.26

95

0

.26

92

1

.52

0 11

7.5

E

xx

=1

.55

M

$i

102

.49

1

4.4

5

11

6.9

0

.1

40

9

1.

14

64

r=

0.9

98

6

Ut

?O

-d

e<J

,3-

dir

0

.26

95

0

.26

92

2

.02

4

26

9

Ey

y:=

21.0

Hsi

246

.57

19

.4

7 2

66

.0

0.0

79

0

1.0

91

0

•=

1.0

15

1 9

0-

de

<J,3

-d

ir

0.2

69

5

0.2

69

2

2.5

20

5

11

E

zz=

1.5

5

Msi

4

80

.07

2

4.4

2

50

4.5

0

.05

09

1 .0

64

4 b

=0

.97

09

'JO-

de

<J, 3

-d

i r

0.2

69

5

0.2

69

2

3.0

20

8

71

Gx

z=

0.5

2

Hsi

8

30

.77

2

9.4

1 8

60

.2

0.0

35

4 1

.04

84

E

?2=

1 .5

27

9

0-d

e<J,3

-d

ir

0.2

69

5

0.2

69

2

4.0

20

2

02

0

Vx

z=0

.49

19

68

.82

39

.38

2

00

8.2

0

.02

00

1 .0

26

0

62

3=

0.5

36

9

0-

de

<J,3

-d

ir

0.2

69

5 0

.26

92

5

.01

7 3

97

0

Vx

y=

0.0

23

38

35

.11

4

9.3

3

38

84

.4

0.0

12

9

1. 0

35

2 'J

O-

de

<J,3

-d

ir

0.2

69

5

0.2

69

2

6.0

05

67

80

V

zy

=0

.02

3

65

85

.70

5

9.1

9 6

64

4.?

0

.00

90

1.0

29

5

90

-de

<J,

1-

d i 1

· 0

.26

82

0

.26

95

1

.02

0

39

.1

31

.39

7

.71

39

.1

0.2

45

6

1 .2

45

6

90

-d

e<J,

1-

d i r

0

.26

82

0

.26

95

1

.52

0 1

15

.3

Pla

ne S

tress

10

6.2

6

11

.72

1

18

.0

0.

11

03

1

• 08

51

r=

0.9

87

6

90

-d

eg

, 1-d

i 1·

0

.26

82

0

.26

95

2

.02

4

'267

E

x x

=L

5

5

Ms

i 2

53

.70

1

5.7

5 26

9.4

0

.06

21

1 .0

52

4

a=

0.9

99

0 'l

0-

de

<J,

1-

dir

0

. 26

82

0

.26

95

2

.52

0 5

10

Ezz

=21

.2

Hsi

49

2.1

6

19.

71

'51

1.9

0

.04

00

1

.03

62

b=

0.9

6G>5

9

0-

de9

, 1

-d

i l"

0.2

68

2 0

.26

95

3

.02

0 8

65

G

xz=

0.6

5

Ms

i 8

49

.1

4

23

.79

8

72

.8

0.0

27

9

1 • 0

18

7

E2

2=

1.5

5!;!

9

0-

de

<J,1

-d

ir

0.2

68

2

0.2

69

5

4.0

21)

20

30

V

xz

=0

.02

3

20

07

.98

3

1.6

8

20

39

.7

0.0

15

8

1 .0

110

612

=0

.67

7

'}0

-de

<J,

1-

d i r

0

.26

82

0.2

69

5

5.0

17

40

20

3

90

7.6

3

39

.63

39

47

.3

0.0

10

1

1. 0

28

8 9

0-

de

<J,1

-d

ir

0.2

68

2 0

.26

95

6.0

05

6

'(9

0

67

04

.71

47

.52

675

2.2

0

. 0

07

1 1

• 01

27

- Be a•

<:1 i

to;e

ns

ion

s

in

inch

es.

Def

lecti

on

rate

w

'=d

w/

dP

,pin

/lb

. w

'b=

ben

din

g co

Mp

on

en

t,

w's

=s

he

ar

co

mp

on

en

t.

Best

fit

an

alY

sis

b

Y

lin

ear

re<

Jre

ssio

n

of

Y o

n

X;

X=w

's/

w'b

; Y

=w

'tst

/w

'b;

Y=

a+bX

t"' ,.. N

\0

....,

0\ ""

"'L···

-.-·

Page 32: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

TABLE 5. SUMMARY OF FLEXURE TEST RESULTS

(Extensional and Shear Moduli in Ms)

TestCondition 00, 3-dir 00, 2-dir 900, 3-dir 900, 1-dir

N 22 22 20 21 1Ell 21.26 20.96 - -

E22 - - 1.527 1.552

E33 ....

G12 - -- 0.677

G13 0.652 0649 - -

G23 - - 0.536

26

W LoCkh'"d-CaAfrbnf Copany

Page 33: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I - , . - . -.-.-. , - . . . -- Lit 29763

50 0 0 . ~..-

I3000 .- -V-

I ~2000 .

1000 3.. . . -

j 500 9f0 beams .-

I -,. .... ~ l - -dir ti~

I -300 - 3

. - 2

1 300 - / -AE 1 00 -a 3

3 9 0 beano3 3-dir .

1001

10~ - V50 - - , -- -I , - - ~ * 4 -T -

-30 4' 4.6.2 5 .i

Fiur 7. Coprio-o Computedin fr

I~~~~ dean Delfto test TestDat

27

lqwLockheed-Callfolnia Company

Page 34: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

1.5 7

1.4 6

A/1.3 5 -

90-dig beams

1.2 4/

1.1 3

1.0 2 0

()ata from table 4Points represent experimenta dite450 lines represent perfect fit

0.9 1

0I I I0 1 2 3 4 5 6

0 0.1 0.2 0.3 0.4 0.5 0.6xi

Figure 8. - Deflection Rate Ratios Corresponding to BestFit Solutions for E and G

xx xz

28

-LoCkheed 2Cua~rori Conpany

Page 35: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I

LR 29763

I Approximate Method for Shear Calculations

jShear deflection occurring in beams is usually estimated by assigning a value

to the Timoshenko shear coefficient K in the relation,I

Wol-ff dx dx + 'fS dx (7)

Here the first term is the Bernoulli-Euler bending deflection found in

handbook formulas; it recognizes no restraint of section warping. The second

term is a "shear correction" which includes all other effects, presumed to

cause a shearing type of deflection. K is generally thought to be a section

property that varies only with section shape; various sources cite values

ranging from 2/3 to 1.0. Consideration of the shear stress destribution in

beams makes it clear that K may vary over the span (Reference 19).

Therefore, any value which is to be used outside of the integral as in (7)

must be specific not only for load and section but for span.

The results of the current study can be utilized to develop rational values of

K. Such data, obtained by introducing the appropriate values from Table 4

into (7) and solving for K, are presented in Figure 9. (For the 900 beams

loaded in the 3-direction, the value of E was taken as E 22/(1- 21 V12) in

J accordance with representation as plane strain.)

Reissner (Reference 20), and Nair and Reissner (Reference 21), working from

fundamental energy considerations, have established upper and lower bounds for

the shear deflection that occurs in a beam which does not deform locally at

the load and support stations. In the 90-degree beam loaded in the 1-

direction, the high fiber stiffness produces boundary conditions which are

closely represented by Reissner's model, and the resulting values of K, as

plotted in Figure 9, are seen to lie close to the prescribed bounds calculatedI" Lockheed

S-Califorw Commo 29

-~*--'-~ *'4~~- - '~~-- -

Page 36: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763.

1.0

0

0.9 ,

O-deg beams0.8

A

2.0

AA1.5

S.0 90-dug beams loaded

. in 3-direction

0.9

z 0.5

1.0

90-deg beams loadedin 1-direction

0.9o~ ... _____ ' - 0.8

Thor.upr8ndloe bouds (u 21)

I I I

04 8 12 16 20 24

Span to depth ratio L/h

Figure 9. - Variation of the Timoehenko Shear Coefficient

with Span and Direction of Load

30

"wLockIleed-Calbrmi. Coalp

I

Page 37: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

~I

LR 29763

from Reference 21. When the load is transverse to the fiber, however, local

deformation at the loading station is significantly greater, and consequently

jK for very short spans is increased and may exceed 1.0.

These differences in the value of K are produced by variation in the way shear

is introduced into the beam, interacting with section constraint. Shear

stress distribution adjacent to the loading station for the 90-degree beam, L

1.02 inch, loaded in the 3- direction, is contrasted with that for load in

the 1- direction in Figure 10 (data from the relaxation solutions). The high

peak stress and distorted distribution associated with loading transverse to

the fibers tends to produce large section warping. The central section cannot

Iwarp, however, and adjustment to this condition reduces overall beam de-

flection. Thus, short beams with low E zz may appear to be stiffer in "shear"

I than those for which E zz is large.

Accuracy in the calculation of K is adversely affected by limitations in ac-

curacy of the current set of relaxation solutions. While these data have a

precision of better than 0.1 percent, they suffer a small error as a result of

the finite dimensions of the grid. Such errors have a greater effect on K

than on the shear modulus, because after Gxz has been evaluated, the relax-

j ation solution values enter once again in thewtotal term of Eq. (7). and in

this case without the benefit of multiple points. For cases important in

j design, further investigation is desirable to confirm the results and to

establish a broader basis for extrapolation to other materials.

IIII

" L ockheed 31-CAWO A COMPWy 3

k _ _ . . .. ... . . . . .. . . . ... . .. . . . . .. .. . ... .

Page 38: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

+0.5

/ / / /

"\ / / /" 90-deg bum, L=1.02

\ "\ ; / loaded in 3-dir"\ i I (parallel to fibers)

0 0. 0.2 0. 0.4 I!\ \ ;.i*. i\ \ '

i ' \ - \ -\.' \ \ '

I \ \ \ , \"

" =0 0.1 0.2 0.3 0)4 0,8, \ \ \\

-0.5Central

loadstation /+0.5

/ / / */

.1 ; / ./ /

90-dig bum, L:1.02loaded in I -dir(transverse to fibers)

\~. if i ii ;; * i

'I1 ' !

I, \ \ \\

x0 0.1 0.2 0.3 0.4 0.8

*\ \. \ \ .-0.5-

I I * .. I I I I 1 I a i i a I I Ii

Shw srew -- I I- One ksl

Figure 10. - Calculated Shear Stress Distributions for

90-degreee Beams, L = 1.02-in

32

")Lockheed-CaWA0n7 CoiNpW.y

Page 39: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

iI

LR 29763

I Overall

Where data obtained in the axial load tests and the flexure tests overlap,

only small differences are seen to exist, and these discrepancies probably

represent the accuracy of the test methods. By taking rounded values which

are consistent with each other and the indications of transverse isotropy, aS ndepen'dlently evaluat

complete set of the n elastic constantsAis obtained and presented in TableI 6.

.These data represent the overall results of replicate tests and various test

conditions. Scatter of test results with different test procedures is no more

jthan a few percent.

These results were derived by assuming linear, orthotropic elasticity, an

assumption justified by the structure of the material and the linearity

exhibited in the basic load-deflection data. The fact that the final results

provide a complete, self-consistent set of properties confirms this model and

appears to refute suggestions of non-linear elasticity relations found in the

literature (Reference 16 and 17, for example). However, the scope of the

current program with regard to stress range and condition is insufficient to

resolve this question. For the type of loading and the material tested,

simple c-thotropy provides a satisfactory model.IIII

w)'Lockheed-CaklO d Compan 33CAMOMM coff-

Page 40: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

TABLE 6 OVERALL SUMMARY

Elastic Constants of T300/5208 Laminate As Tested

I PROPERTY VALUE

j(GPa) (Msi)

E1 1415. 21.0

E2 , E3 j 10.7 1.55

G 12 G 131.50 0.65

G3.70 0.52

v12 Iv13 03

v23 9v32 0.49

V2 1 O310.023

nockheeo-C*A~7hnb C1PWY 34

Page 41: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

5 LR 29763

j CONCLUSIONS

A complete set of the nine elastic constants experimentally determined for a 64-

ply T300/5208 unidirectional laminate is presented in Table 6. These data are

based on multiple independent experimental determinations, with the overall

means of the test values modified slightly to obtain a consistent set.

The results agree with values cited in the literature, except in the case of thein-plane shear modulus G 12 The value obtained here (0.65Msi) is somewhat lower

than that expected from + 450 tension tests (0.80 Msi) and the Pagano torsion

test (0.87 Msi), and substantially lower than reported for ultrasonic tests

(1.03 Msi).

The results obtained confirm, to the limits of the experiment, that the elastic

stress-strain relations are linear and that the material is transverse.Lj iso-

tropic.

Calculations of the Timoshenko shear coefficient indicate a substantial varia-

tion with the orientation of the orthotropic axes of the beam and with the span.

In some cases the calculated values exceed by a considerable amount the recog-

nized bounds for a cantilever which has slightly different end conditions.

Boundary conditions are thus seen to have an unexpectedly strong influence on

the deformation attributable to shear. Such an effect could explain variations

in performance associated with different test procedures, and would increase the

5 problems of analysis and design.

I

I

W, Lockheed

Page 42: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

REFERENCES

1. L. D. Fogg, M. Feng, and J. P. Pearson, "Design and Analysis Methods for

Composite Structures," in "Independent Research and Development Plan,

1980," Lockheed-California Company LR 29364, April, 1980, page 7-251.

2. L. B. Greszczuk, "Shear Modulus Determination of Isotropic and Composite

Materials," ASTh STP 460, pp. 140-149, 1969.

3. P. H. Pettit, "A Simplified Method of Determining the In-Plane Shear

Stress-Strain Response of Unidirectional Composites," ASTH STP 460, pp.

83-93, 1967.

4. J. M. Whitney and J. C. Halpin, "Analysis of Laminated Anisotropic Tubes

Under Combined Loading," J. Comp. Mat., Vol. 2, No. 3 (July 1968), pp.

360-367.

5. B. W. Rosen, "A Simple Procedure for Experimental Determination of the

Longitudinal Shear Modulus of Unidirectional Composites," J. Comp. Mat.,

Vol. 6 (1972), pp. 552-5541.

6. C. C. Chamis and J. H. Sinclair, "Ten-Deg Off-Axis Test for Shear

Properties in Fiber Composites," Experimental Mechanics, September, 1977,

pp. 339-346.

7. R. D. Kriz and W. W. Stinchcomb, "Elastic Moduli of Transversely Isotropic

Graphite Fibers and Their Composites," Experimental Mechanics, Vol. 19,

No. 2, February, 1979, pp 41-49.

8. G. Terry, "A Comparative Investigation of Some Methods Of"Jnidirectional,

In-plane Shear Characterization of Composite Materials," eCos0tes,

October, 1979, pp. 233-237.

I,4Lockheed 36-C Tforn Cmwoy

Page 43: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I

LR 29763

j 9. K. N. Lauraitis and P. E. Sandorff, "Effect of Environment on the

Compressive Strengths of Laminated Epoxy Matrix Composites,"

1 AFML-TR-79-4179, December, 1979.

i0. P. E. Sandorff, "Experimental Mechanics - 1978," Lockheed-California

Company LR 28938, December 14, 1979.

11. G. Stoeffler, "Determination of Torsion Strength and Shear Moduli of a

Multi-Layer Composite," J. Composite Materials, Vol. 14, April, 1980 pp.

95-110 April. 1980.

12. N. J. Pagano, "Shear Moduli of Orthotropic Composites," AFML-TR-79-164,

March, 1980.

13. M. Knight and N. J. Pagano, "The Determination of Interlaminar Moduli of

Graphite/Epoxy Composites," presented at Mechanics of Composites Review,

28-30 October 1981, Dayton, Ohio.

14. H. D. Wagner, S. Fischer, I. Roman, and G. Marom, "The Effect of Fiber

Content on the Simultaneous Determination of Young's and Shear Moduli of

Unidirectional Composites," Composites, October 1981, pp. 257-259.

15. D. E. Walrath and D. F. Adams, "The Iosipescu Shear Test as Applied to

Composite Materials," to be published in Experimental Mechanics, 1981.

j 16. H. T. Hahn and S. W. Tsai, "Non-Linear Elastic Behavior of Unidirectional

Composite Laminate," J. Composite Materials, Vol. 7, January, 1973, pP.

U 102-118.

-4LoLckh~e- CaI/fo# W ConpW&y 37

___________'________________________'______________-_-_____-_--__-____-_-_-.-_-_-

_....__ll I

Page 44: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

17. J. G. Davis, Jr., "Compressive Strength of Fiber-Reinforced Composite

Materials," ASTM STP 580, American Society for Testing and Materlils,

1975, pp 364-377.

18. A. M. James, et al, "Advanced Manufacturing Development of a Composite

Empennage Component for L-1011 Aircraft," Quarterly Technical Report No.

7, NASA Contract NAS1-14000, 14 October, 1977 (Lockheed-California Company

LR 28325).

19. P. E. Sandorff, "Analysis of Saint-Venant Effects in Orthotropic Beams,"

Lockheed-California Company LR 29357, April 15, 1980.

20. E. Reissner, "Upper and Lower Bounds for Deflections of Laminated

Cantilever Beams Including the Effect of Transverse Shear Deformation," J.

Appl. Mech; Trans. ASME, Ser. E, Vol. 40, December, 1973, pp. 988-991.

21. S. Nair and E. Reissner, "Improved Upper and Lower Bounds for Deflections

of Orthotropic Cantilever Beams," International J. Solids and Structures,

Vol. 11, No. 9, September, 1975, pp. 960-971.

"qgLockheed-CAM7 Company 38

Page 45: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

!APPENDIXI

PAGE

Photomicrographs of Sections of Test Specimens 40

Representative Extensional Stress Strain Curves

Tension in Fiber (1) Direction 41-42

Tension In-Plane Transverse to Fiber (2) Direction 43-46

Compression in Thickness (3) Direction 47-50

Representative Load vs. Deflection Curves in Flexure

00 Beam, Load in 1-2 Plane 51-530° Beam, Load in 1-3 Plane 54-56900 Beam, Load in 2-3 Plane 57-59

090 Beam, Load in 2-1 Plane 60-62

Representative Load-Deflection Curves in Block-Bearing 63-66

Load vs. Deflection Curve for Fixture Alone 67

Load-Deflection Characteristics of Clip Gage 68

Table A-1 Compliance Coefficients, Tension Tests in 1-Dir 69

Table A-2 Compliance Coefficients, Compression Tests in 1-Dir 70

Table A-3 Compliance coefficients, Tension Tests in 2-Dir 71

Table A-4 Compliance Coefficients, Compression Tests in 2-Dir 72

Table A-5 Compliance Coefficients, Compression Tests in 3-Dir 73

Representative Computer Print-outs of Relaxation Solutions 74-76I

39

1WjLockheed-California COMPWY

- - - -~-,

Page 46: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

.~

~ ...

... :::

:-0

0'(")

35

: Q3

· (1)

~(1)

:::!~

"1:5 ~

~

£:-.

::::

Fig

ure

A

-1

-S

ecti

on

s o

f F

lex

ure

T

est

S

pec

imen

s 0

° N

o.

1 (le

ft;

an

r' '3

No

. 1

(rig

ht)

, at

15

x

Nag

nif

icati

on

. D

amag

e to

e

xte

rnal

su

rface o

f o

o

specim

en

w

as

cau

sed

by

test

mach

ine

gri

ps

. " ;;o

N

\D

-...,J

"' w

Page 47: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LP. 29763II '

. ............. ..................

0

cz

h i .-. '-

.............. ........ ...... ......... ... ...... . .. ... .. .... .o .

lot

I.. . . .",,,.. ..... .........

:. I S i..., ...... ..

i - ,

* i -I,

-L- -

.... ... .I ..I -"I I I I il .. . i .il- ...l - iIi41

Page 48: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763 1

I

Ir.. ,: ............ ..........................................................................................................................................

1................. .........

.......................... ,

D.. .......... ........... ..... .. ............. ...............OZ z........................ ....... . ....... ..... .. ... ....................... . ..

..... .. ..........

.......... ........ ............ .. .............. ;......W...

Iz >

nki'oclrheed-Ca"W7 COW 42

Page 49: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

T5. ... .... ... .. ... . .... .. .. ... .. ... .. .... . .....IT

0 1

... .. .. .. ..........

.... ... .. .... ... ... ... ... ... ... ... ... ...

ws .. ........ .................. 0 ....................

=~~IIch

I _ * .Z

.. ... .. .. .. .. ... . . .. .. .. . ..-.. .. .. ..

... ... ... .. .. ........................0 E-

.~~~~~~~ ~ ~ ~ ~ ..... ... ... . . .. .. ... . . .. . .. ... ..... ..... ..... ..

x

LoItt

.. ...........I. ...................... .

0 00 0 0

I 0 0 0

tr..

1-JPLockhftmd 43

Page 50: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

T 110

COONC

Z Z

1- 0

i~nfn 9L3

....... .... ........t. ....... t ... ...f. .......l. ..... . i

w ClI..... ..... .... .....

00

U, 0

(z~0

j.................. .............. ............. ............ .......... 0 J

V) r. , . NW I W

0. - 44

NO.oIklcammmcmv0

Page 51: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I LR 29763

.. ........ ...

I-Inr

... .. .. ...... ..... ....

w1 z.. ....................... . ....... .... ....... .... ................

Li ~.b4

Z 0

I ~V±

wOokhe 45

3At/ .&7J o

Page 52: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29 763

N N

...................... ..................... . . ......... . .... ......

.. .. .. .. ....... .. .. .. .

~bin

10 V)0-i (n

.. ....... ................. .........

0 N 0 L

'M bkd kf e 46-

CaftMAN CflW

Page 53: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

T I-

................................... ...... ............ ................ .......... I

I iI In

'qJ'Locheed-4.....m ~ .. .... .... .....p. ..w. .. .... .... ...

Page 54: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

10 r-

* .

kA.

11-

.. ..... ............... ............. .............. ................ ...........

tom ,4-

CIO~1-

U"P-4U1 X- 01

.. ... .. .. ......

48-

Page 55: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

.t ~...

-.

~()

~~

r;i" Ia -l

:­\0

·=\O

tlO

.

:31

}1)1

) •

TE

H;

I Ot-

VC

OI"

IPR

ES·;

l•JH

T

ES

T

·~1)-

·~0-2

Ftl

t1X

L

OH

D

CH

STR~lH

CH

STRESS.M~X

1).5

.5

1)5

1)

--~-­

':).

-_ . ..-

..

TE

ST

R

IJH

\

30

54

IJI)

.S

o.

TP

Uti

C.

PC

T.

TH

I C

Kt-IE

·;·;

li

i D

TH

·;

TR

H 1

t-l •

tt~X

.: .

.. .

.....

.:

....

(1'~1)

0. 2SS

·~

1). 2

-57

7

20·~2.

7oo

o .

i ...

.....

......

) ...

......

......

... L

........

.......

......

.....

_ ····-

--~---

-·--·

.......

) ...

.......

.... .)

......

......

..... j

........

.......

......

.......

......

.

s r:~i::::: !:

:= ~ ~~:::

:I::: : :::,:

: ::!:_

:~ :Id ::::::

[: :::r : ::

I ~ ~~

~ ~

~ I

~ ~

~ ~

~

.30~3.

'--------

··---~---·-

·-····-'

·-··-

---~---·---

----·1

-···----l-

---······--

--l-----··

--···~---

--·---------

-1 ..........

......... \

...........

...... .

; ~

~ ;

~ ~

~ f

2ee

e. ~---·

-----1

-----,

---J-

--,--i

-----.-

----1--

--L__

_ . -

---

teee

. 1 ...

........

........

1 .........

..........

l········

---·

________

_____ j_

____

__ --J ..

............

.... l---

--·-·--

-L .....

..........

,L .. ___

__ L, .

.... _ .

.... ..

l 1

lCOM

PRES

SION

IN

1TH

ICK

NES

S D

IREC

JIO

N (3~DIR.)

l l

l TRANSV~SE GAG

~ ON

FA

Ct

1 j

l

-·~:

~ ----

r---· -

---~-

--:

-·-·-

·r··-·

·r··

·~----

·---~

---l

----

-10

00

. -.5

ee.

e.

.50

0.

too

e.

1.5

00

. 2

00

0.

2.5

00

• 3

aee •

3.5

00

. 4

00

0.

MIC

RO

STR

AIH

t'"

' :::

0

N

\0

......,

0\ w

Page 56: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

0 Iz w

zz

Mrf

-. kc'

x0

P-~'w t

_& 0 C)kit- ri fl 10

Lt CLT

50

Page 57: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

V4-

toN

w w

NT W to

( T O '-4

SInL&J L&J .

N" N

0i0

cc a

~x

r-J-J CI I_ _ _ _ _ _ _ _ _

CII

mCaEnwTW Cnp~=3 " "51

Page 58: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

coIa)ItoI

wt

m~ I t

C') kDN %

tZ r

1 6-

C) S) t

m q

nN

xX N

Z:c

r- C-i

- r-uwU)J It) - 5 -

nUI 1- " L

... JL~J I to-LL. xTT TT TT-T--

0-j

'WkJLocklieed-CamomA commpy

52

Page 59: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

r LR 29763

I - - n - - - - - - -,

1*1 IV;

If CDI - C

I1IIi z~

IC'C CDi- - - - -

Ix zM-C I

U. m~

I In - e U)

LA~

uJ-------------------------------------------------D

OD w N

CAMIA (fl41417

Page 60: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

co

CID,

1'-

C t o C)D In

w w -4

(T) .4 CD

LaLI I_ _ _ __ _ _

Q CI

x0

C.oD

wLUA

r-u CD ? U

win in:3 1-4-4 U)

rri -rr-i W""T~ -rrr -ii--r---i-

co V N N~

0-i

'wOLockheed-C&Nbrn7V Coffvwiy 54

Page 61: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I"

N11

I'l

C) In~j .- 4

WN4

w wN.(T

V r 4

r w

m- nCU) NLNW- -4 (

.~5.5

Page 62: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29/~63

- -o U-

M MM

M MWWh

O00 to- -

M~~ 0I) J

If- ON

C i r- -D - - - -\ -

- In~- x - -- - -AA

rzaa,

OD %DvNNM M M MC

OID 4A l N=

lw,. LocIwexxwfn =oov5

Page 63: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

Iw

U C

,N

x x CD

X: NxN

L&LAJ CI

(.- )u L

U)

Ii La II

ODr- W V ia.I~I U) )U)c0I~-CJU0

'WIA o~Lyee

cat7/ 1-41-4w 57IBOO

Page 64: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

CD4

(MWW

r-~ I C

- CD

III

LaJra ND --

W4,

x x<x 0

zTNW

LU I in)P to L

LiJI (P C IA

W.4Cf) O.

x I-x xLJ I I cc(

Ln rr?'r ' N w4

y-JP'LoCkheed58 1

Page 65: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

T 1916

I LR2976

I - - -- - - - - -.

w w C

CD0 W

It~ -(

zz

I .- 4 CDX- C

U. CD,

Ile.~

C~D . i

itIL

.- x.

I--xx

CD CD CD C .^( D C 0 0D 0In 0 In *.iCA 0 a t a a a C

CD -.)MN N C D In

n?Lockheed 59-CoaWrme C&O w&fY

Page 66: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

CIDn

to

toNM

I I C (Uf LL&J 4

o~*-4 fn(M

UN

to

NC

-a-

I-- t- D

Li -

-4 '-4 I

- t'- I ~D. IlV WbLL.JO ' 4Ir~-uuCU

L.JIJ LJCME~W~flCD

nk (ileexI-xx WVN

LJ~fl'Z'60

Page 67: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

CD

N U

m m -V03~

X 0X

V-4 v0

~-X

k M7

U S.

I- 0U) C -x - - - - __I~ I-YI

II

In) CD. W) C Jn C---------------------- -4--------- - S

3 0L~keeLIJIIcnww

~> rrr rr rrr rr r-i'TIT ri- rrr r61-

Page 68: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

- tow co C

w wx

-. two(DCDC

I~ -V cC) LL JaD N4

if)'

xEr

-~ a

wi

w. aPV.

N- -u

U) f) 01JIXJ~ .4 U' Li I

I--Z x

aa an 4m aLA x .a

-j C

loLockheed-c&Off COHN-Y

62

Page 69: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

CD (Din c- .

-0- .- B

U) 'W-4

WLW)- . -

Min~

II I U*

-4 V- W

- - - -\ -: U

O" U) Ix

I It

W to - - -4 - wf

1 ~~~~t.. . , ,ixl

-aIoI C n..-... I

-

n?-ockheed 6(I) fl"A) Mijj

Page 70: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

C0N

C0 9%Go-

1 OD,CD t

V)i 010 UC%*'WWOW.

N) N''4-MN

V S

4M 4M -4

p 0-4

-4!C) I-

CwinL iU V)

Nil wl wllr

C; a;cm C ;6 ;G

In 0rV mcu CII

NOLO~keed 6

C&*bm~gCofl1-

Page 71: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I LR 29763

0,

w w

II I(

IM)- 0

-4It 1'% 1

I"IA

wrw

- c;l C- - - - - - - - - - - - - - - - -

C0

NOL- kheeu~ lowCOWV6

Page 72: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

Z~ LL

r') U-)in.

ww 0V), W~c 0

U- -m - - - - j

w ") LA-

* (n,

.A.m ' u) a:-

(M U"r 0 0 -C D n 0

*.-) vIat'MW)w r-a

Ci

Io~ark*) 66---

000 coo"")

Page 73: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

j LR 29763

-4

wwal wo~ a)-- - -- -- - -- -

MI

ww

kiDr- w

o~s'j ~ ;

MJ .X X7

CD

I Ulu7w ii '

I--II-

U' lt) Qf to CjJ" D U) C DCvif IT r) ro)_) %j V0W

wWi~he 67

Page 74: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

cA

C

Opt- ml N

-- 0

C /-

T

1. 1. 3/5 IN. /

c- ,--1.I 4. V/EN. (.o34 I %./L~B~

A "-

-4 V UMNLO2)DI NCI

-- //

I I I L II

.0 ,.".

6T ri F C I P 4~ 6 . .Z..Z B 0

.CAOU70 CbIPW 68 [

Page 75: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

i LR 29763

7A8LE A-/. COlMPLIAME COCFFCIE"NrS

U rNS/ot rpsTs IN FI/ERA DeEcrIoq/,tR.)

___- ___ - COMPLIANCE5-=Ch/~o{u/sL

kALJC6E SPECfJ4N NO.

(ks!i) " I 6,Ia o- 1o 0o° No. f 11672-1 /+3 0. o-os/ -o,015,19

244 0.05092 -O.0162"

0 No. Z /1767// /+3 0, 6 13, -0. 01-7152+4 o, 06'022 -0.01877

1/77/2. 1+3 0,05/92 -0.01699

I 2.4 0, 04945" -010/80/

0 o, .3 /2044/4 /f3 0,0 4881 -0,0/742.

2+4 6,04802 -0.,566

10-40 0 No, / //472/2. 143 0.04834 -0,0/488244 0. 04 75 a,014.

0* yo.2 /1/767// /'i3 0,04817 -6.01475"204 0.04698 -

1767/2 1+3 0,04826 -0.0/473

02 2+4 0,047569 -0.01498

0* No,. 12011 .*3 0,047/7 -0.01i'640-5 0' o.1244 0.04.674 -04/0

40-6-0 06 I. f 116721/2 /43 0.04657 -0,0148oI- 2"2 4 10. 04 53 -0.0148t

0O Ho.2 /W747// 143.10, 04648 -0.0456(o

j 244 0. 04584. -0.0I604-

/717/2 /+3 0.047/0 -0,0i44.T1 2.o* 0,04 21 -0.0/49l7

I I_

M /EAN 0.044/ -0.0150 -0.0/47

COEFr. VAR. N 0.014 0,027 0.030

-,iJockhed-C fa.If l CIGW 69

Page 76: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 2976

,BL E A -2 , CO M IPL lANCE COEFF /C lE r6 L1VT76

CQMPRE56ION 7-ssII-fE. DIROCr,0N('wr)

NO. RAM5~ COMfPLIANCE- .5.: )e/c: u/

SPEIME 7EsT rsTRES5

0No.2 JIO-51/4 I, /13 6, 0455-Z -0.0/464 0.0146.5Z-A4 O.0484(,

06 /yo,z2/.5/5 /-/0 /i#F3 0. 05,0/8 -0. 0/6 0

244 0.04901 -0.015'83

0* No, 5 /20462 IS-lI / 3 0.04 9577 0.0/530244 6,04878 -0.0/390

Nt 3 3

MEA N 0,0492 -0 1 0/ I -0.0148

COEF. VARA' 0.0oleo 0.0Sf. 0. 0&6

nJLockheed-C--n c~ 70

Page 77: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I LR 29763

' I7TA S4E A-3. COMPLIANCE" CQEFP1CEAfr.S

TENSION TESTS /W-PLANE, TrANS VERSE (2-.OR,)

I 5PECIMEN TESTr 5MAESS A6 COMPLIANCE ii ei /iry 4A/piN6. R.AME -,1 2'3

50 No. 11676/72 0-3 /+3 0. f.486 -0.0,604I 2.4 0,6 '484 -0,3104

s 50 Nd. 2 /1761/I 0-3 I+3 0. 43.97 -0.0153 0305(2+4 0. to 3/2

11761/2 0-, 143 0. 1537 --. ,15"!Z.* 0. 6T7T" -0.3078a74.63/I 0-4 1-03 0.638. -0,01541

244- 0. 6420 -0.3049

1/7604 0-5 Y143 0,*5/ -00/53.2.4 0.(360 -0.3067

150 No, 3 120SI/I 0-4. / 3 0, 6386 -0.0/5272.04 0.1417 -0.305'0

A' JZ C. (

MEAN 0.643 -0,01561 -00307I

COEFP. VAR.N 0.012 .036 0.007

I

71

Page 78: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

TASLE A-#. COMIPLIlANCE COFFFIcismrscampIRE6ssio risTs IN- PLANE, TRANS VERSE (2-D)

SPE'C(MEN TrESr STR~rs COfPIAJE rvEi/pLNo,. RAN6( AG

O$I/Z 32

90O0 No, 114741/S /-2 1+3 0.627(a -0.0 /4732.4* 6. el341 -0.302Z

16/& 1-3 1+3 06413 -0.013732.#4 0.?,o36 -0.29/8

50 No. 2 /2637/2 1-3 1*3 0../ I5-a -6.1S442,t4 0,6124 -0. 2067

H EA N 0.628 -0.014(o -0.297

COEF. VA RN 0.01$ O.069 0.0/8

72

Page 79: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

I LR 29763

IrA SL E A-5. COMPLIANCE COEFFIrItr/yrs

COMPRiEssION rEsrs /I T04CKNE55 DIRECMTON (3-DIR)

I7"E5"" 7"-.ssCO--P-OANCE" S,.i=20ej/<)4,rp

SPECHKr TEST 57r~RESSC0 LIN .= (;gpiP401 RAM6E &~I S

(k 533 5 3 -Z

0 No. 2 12032/5" 5-10 2+4 0.& &08 -0.0/7,5C5"-TlEQ) !/2032/4 (.-/9 2-4. 0. <722 -0.0/78

0No. 2 /2066/2 5-9 2 4 0.(,.33 -0.3522

L.)120557/3 2-/J2 2-t4 0.(to ,5" -0.3:59 /

1zoSS/S S-/8 2*4 .44o2 -0.35"89

90-90-z /3054/4- /-3 t#'3 0,670S" -0.0/6/

(/7-TiE 1 ) 204 0,4878 -0.3330

130S4157 2-f /# 3 0.1t 7 2 -0.015324. 0.679+ -0.3274

1A' 9 4

SA1f EAN O. 47 -0.0167 -0.344

COEF. VARM O0+04- 0,072 0.043

I

-Lockheed

73

Page 80: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

ITo Z 0 0 00 0 0000 rj ' l 0MM 0P -i , n0000I M0000 -000 -0000000000CP)

0 w V M n ;, M M Ln 000 Ln -0P- M 00 ;Ni 0 0 A 0 N0, r M q, N

CAn C -

0 0 0 0 0 0 0 0N00 0-T0 000 0 00 0 0 00 00 0 0 0 0 0 0 0

00 0 0 0 0 0 0 000 "aW)M0 U InO *:;0M MM 0 00000000000000000m00

CA0 nC Ai TM'VoC W '0 fZ 0W: N0W~lO U0 'N0 N~~W -CDClfn01f- .

N 'T CA c 0-I l r; ,'v PI "I ' lM A-T -c v , nCA C A 0 1 . w m N N I on I ---0 T ;:0 SM;0 U A

c;t oCr, ,a , TVaC ,01VMI Ar oi' 0oooO M NoIToIooo oo0 0oMo0 N -Tof'ooM CA O To

0. M Mi A0MMC )N0 % I 0VO AI -0C TI -004 -; CAu AW V 0C )qV 0T-M0MM , D ICICCM M rww lT lw r-

IT K~~r M 10I A0C ,c 0 ;MC 00MN0 r- q0 44 AU ,Kz 0.-M

0000000000000000000!000 00000000000000000000000

---0000 000 0000 000 000 000000000000000000000

3-- n N m In OO m oOaOm 0 10 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1000 0G0n 0 0 0 -T 0 0 00M N

,co -moo r-TPTro )n.,0WO ,NC D4 ,C )0M0M 00' -, :: CO "I;MwC D'0 rC T tV0M nI ni rfC

N l0 00 00 0 00 00 0000 0000000000000000000000N~~q-fTO MOU-N O-A-l-

00 M 00 0 00 00 00000C 0000V 0 0n0O nMW %C A0 ,

0 oo o o o o oo o o o o N AVM: , ) DMMC )0i11 00000000000000 00 00 00r, 0 00MO ~ wO - f' -00 P)

rj CJ 0 40 0 000000000 N m NN-00000000 VV V- .N0M;0 ' O-

00 0 00s T V)7:0 L)0 i I0 'q NNCo0 t - M ACA0NMM AeTNW0

0Cdw~ Cwilv [1_1T n loT :o m OMKV 0N00C -0 -C J0VL)

Page 81: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

Ii 29763

- 0 0 0 0, 000

; ~ ~ ~ ~ ~ ~ 4 M,0r-M-hAoF N M 17 0,N

0 C- Q M

*~ ~ 77 00 0 00 0 0 .. 000000000

*M OV 0; 0 aN -q -0 NI 401NMv- Q0

0,, INN',,0 ,II~~~~N N C4 C14C00g4lr0Q MWO'C,4 r4fl

o'. ri r M N In N InON-0 T0 N IN 0 In 0

0 m*N qn loo N W N0 N0L N V00 0 N 0 I 00000000

CA ON N 01v I n v0 M -0I0M .NN 1 ,0- l U 1 0I U1 ---1O0I N t1tq l' C! 0- 11! 1110N0-0- IN0IN M N 0 0- 0 -- - C .

Cl~ ~ ~ ~ ~ ~ ~~ : !C 00N00PO-~ T~'II00I 4 V,-rMCN40N0000

0 0--00)420 M-~~~4o t0f l~~ 0 0 000 -4- - r~IO ~ o0 .co~ 0 0 0 000v0 0 0 v vIn 000000000000

00 0~0 SPN N w 0 ~0 IT 0 r I NI n OD 0~- 0 -D NOO >'OCT0O1.40 0 0rI ~ ~ ~ ~ ~ ~ . Cu4 C. 0!O JIlN -(0 00 0- ' C O 0 0-fr, C00 6-'~4

a00..-V I Imr-401'.-OfI C0. D,OD-a 0 n 0 0 0 0 0 0 00 00 00 a 00000IC0000000

C! 01iOOJm wNM- 1 t1 M0 1 0 c,00.-0Mn00M oN -WJ 00NI m rI Nv poI 1 Ill N a INIt)M :

Lr 40NI 4M--0~4C0O 0---- - Ar~~qU~IC0~~V~~m0 0-r- 0orw~4 -r T O w

0,00'O 400~-N~0 WN N ~ !N 0- 00 0V 0 0 0 C 0~ 0- 0C 00N

: ri: - - 0 d I O - - -I I I I I I al I I I II I I I I

a w 0 lo v 0INN0; 0; 1, wM .00 0 0 0 0 "N-000000000

w0 " IN ?1 , I N - -N M M-- 0-~ w 'r00 ; 0 0.N V 0 13 0 0 N 000N 40N0 0000 oN M 0 1. M . N 0-

M O 0100 0 *N , 0w 1 v NNNW WI O o, e. MM75X 4Lckh CD N D. . 40o0 D N; ,1 r

-C-- -

Page 82: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

LR 29763

0 n -. * 0 '- 0 CAo r" .1 cc0 N 0' a r'l 0

0 N 0 1m 0 C r. m0 0

oo0 0- r0 0W 0o 00 N

0 M Ln oq N l 0 ,G 1o W W - 0 00 '010 7

0 Ll r- co '.0 oI n ) mo r N n r0- 0i v00 C. 'C m0 0' 0' NA 0' w0.00

00 00 0 0 000o 01

0 0 0 CA a1 oI 0' N N N MI4 aCAIII A c01'- 99 0 01-0 0N AMIWli 01' 0 0

3000000 000000.-

30 000 000 00 0 000000000.:

00:02000000000000000000 0 0 0 0

- r-00 0CWI - CN a 0 0 0 0 00 0 000

00 N MC0NN ' N 0 r .WI'0N M0 C. '0c u, n C

0~~~~O f0 0' 0 C00 0.- UN ONC 0T 11 1'- '000 C- 0TO

N ~ 000 N 01 1 000000000000 z 00 00 00 0 o o

0o 0 N 0 .0 0 a 0 '0' C 11 C1

0~ 0l p CC M N MI 0'1 M v0 0 0 N cc cc V

0 " U ONIOO'OO_ 00OCC.- 0 -0 N Clq r- -A) -0'1-0 '.- 00WV0 000n000n00 M000 M0 E0~ ~~~~~~~~~ 0N0C O O O O V CA CA 'T--'- 0 0 00 0 0 0 0 0 0

11. .. . . .. . .. . . 000000000000000000000000000 04.-0000- 00000000000000 0o00 0

00000000000000000cc00.1 ~ ~ ~ ~ ~ ~ .0 0Ic A0o T NC

0 .- MM 0 0 0 D, 0 co OUjN N o CA ON

0ONNOO.0'o0--- 0 ' 0 0C'000~000

~ 'C11~~~01 NM 1 2Mo 00 0 0 0 00 A-0 0 0 0 00- C ' '~Nr .C .00z

C, M M n lI MM 1 p00m H 0000'ICI00 1

C ~ ~ ~ ~ 00C 00NO .0CcOO' 00'.C 0N 0, M

mvv~~ ~ ~ ~ '0 Ny 0N 00. 1, ON 0 Nn 9 N N 0 0 0 0 M r01 M r- 0 M 0, 0 . M 00 00 .0 ON N4 C?' '0 0w,? r N0 v o V . mOo MCI

0 CIC 0N J 1 ~ 0 C '' 11N 0 W~ CC CC 0 0

00.- - C 00 M0'NCCCVWIICo. CA0 '''''' 00 0 0 0 0 0 0 0 0 0

0000 0 000, o0000 0 00 0000000000000 0 -.- A. CAN00000m0 0000

000000000000000000000000000CCm

0"Nc 010- C '' 0C0.-0'00'0'C,

cc N, 0? '-C-01 -0 0N 0 00 00 0CCC00-G -0.0N N'00N 1C C000

00 0 0 0 00Z- 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C 'Ci 11 2 A-7- C 4 cG 0 -00000V0O0000000co 0, -4rC a

"10 000 00 000 0000a00 0 00 0 00 0 00 0

00NN~ N~N N0 ~qq0'000N76n oC - 0 I I-.0.'-0 0CW0IINI0 0 0 0 0 00 0 0 0 0

aa ni 0I0''1'N0N-0' 00WN I0wIt'

Page 83: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

ENGINEERING REPORT INITIAL DISTRIBUTION LIST

OAT6 0O06L SECURITY CLASS REORT NO.11-30-81 n) Incl. LR 29763

TITLE APPROVAL \-

VF!: 'A L FLEA~ TIP;T J. Fairchild

SF'tLYET'N COMMENd~a RNGINCERING1COMMEVaI..E IN H)GUACH RKPORTS1* O~RIGINATING ORGANIZATION INAMIE SNUMBEt --pR99UT AVAJ.AToF op p.

74-71 Structures & Materials Laboratory R7/JJ. /1tj6'/t?UWOIRWA 41 5707 ... .300OAt AxI tiii sATAW ssnc Pot

CeLAsS WKORE EWA ____________________________

LIMITATION ON ACCESS:UNLESS LIMITATIONS ON SUBSEQUENT RELEASE OF THIS REPORT ARE STATED BELOW, COPIES WILL BE MADE FREELYACCESSIBLE TO ALL CORPORATION EMPLOYEES. (IF LIMITED. SUBSEQUENT RELEASE TO OTHER ORGANIZATIONSREQUIRES COMPLETION OF FORM 7229.)

LIMITED TO: - - -_

REASON. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DATE ONWHICH LIMITATIONMAYBE LIFTED:------------------------------IS THIS REPORT RELEASABLE TO NASA/DODIDOCI LIBRARIES? E3YES M NO

DISTRIBUTION ____ PUT '*X" IN PROPER COLUMNSCOPY I ASSIGN COPY NO. TO HARD COPIES ONLY. EX- IN- TYPE N

NO. 2 LIST MICROFICHE AND ABSTRACT RECIPIENTS LAST. TERNAL TERNAL HARDI MCRO ABSTRACT RE-3 EXTERNAL COPIES: INDICATE TRANSMITTER. (NON 'CE OL VION4 CIRCLE COPY NO, OF REPORTS ALREADY DISTRIBUTED. CALAC) 11CALACI Copy FCE OL IIN

INDICATE ONEMASTER 12 REPORTS SERVICES GROUP X X

0 PUBLICATION SERVICES GROUP.--- -- --- PROJECT

I VITAL RECORDS X x

2 REPORTS SERVICES GROUP x x

3. 4 CENTRAL LIBRARY X x

5, 6 Technical Information Center (IMBC) x ____x____

7, 8 Technical Information Center (Gelac) x x____

9 W. Fehrle/C. L. Hammond, Gelac 72-26/285 x x

10 F. W. Grosonain, IMSC 52-33/205/2 x x

1.1 R. E. Mauri, II4SC 52-31/204/2 x x

12 R. F. Hartung IMSC X xL

13 E. Burke/0. Hoffman 1MSC x x

14~ J. M. W~hitney AFML via PE Sandorff x

15 N. J. lagano AFM, $I x x16 J. L. liar M.I.T. II Xx

17 E. Reisener U.C. San Diego IIx x

18 A. M. James 76-23 63 A-i x x - --

CALAC FORM S7S9-d

Page 84: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

ENGINEERING REPORT INITIAL DISTRIBUTION LIST REPORT NO LF 2.?763

(CONTINUED) PAGE 2 OF 3PUTI"X" IN PROPER COLUMNS

DISTRIBUTION

COPY 1. ASSIGN COPY NO. TO HARD COPIES ONLY.NO. 2. LIST MICROFICHE AND ABSTRACT RECIPIENTS LAST. A CF

3. EXTERNAL COPIES- INDICATE TRANSMITTER 04. CIRCLE COPY NO. OF REPORTS ALREADY DISTRIBUTED. 40

19 C. F. Griffin 76-23 63 A-i x x

20 A. C. Jackson 76-23 63 A-1 x x

21 R.B. Ostrom " x x

22 L. D. Fogg x x

23 M. Feng x x

24 H. Simon/J. C. Wordsworth 76-20 63 A-I x x

25 W. Richter/R. Simenz 76-30 63 A-I x x

26 E. K. Walker 76-02 63 A-1 x x

27 J. Wooley 76-32 63 A-i x x

28 R. Stone 76-31 63 A-1 x x

29 G. Haggenmacher 76-23 63 A-1 x x

30 R. Contini 76-23 63 A-i x x

31 I. F. Sakata 76-23 63 A-1 x x

32 G. W. Davis 76-23 63 A-I x x1

33 J. E. Rhodes 76-20 63 A-i x x

34 M. A. Melcon 76-01 63 A-i x x

35 J. Fairchild/W. F. Dryden 74-70/71 229 2 x x

36 W. E. Krupp 74-71 229 2 x x

37 R. C. Young 74-71 211 2 x x

38 S. I. Bocarsly 74-71 229 2 x x

39 D. E. Pettit 74-71 204 2 x x I

40 J. T. Ryder 74-71 204 2 x x

41 K. Iauraitis '" it " x x

42 J. P. Sandifer of " x x

43 Y. Tajima 74-71 229 2 x x

44 R. N. Ketola/Dept. Files 74-71 202 2 x x

45 P. E. Sandorff (Author) 74-71 202 2 x x

46 W. Brewer 74-75 229 2 X x T-CALA, F(AM 5759A

Page 85: OTICthree shear moduli: the in-plane shear modulus G12, and two transverse moduli G13 and G2 3. There are several direct, relatively simple test methods for I evaluating G12, but very

* ENGINEERING REPORT INITIAL DISTRIBUTION LIST REPORT NO. 1R 29763

(CONTINUED) PAGE 3 . or C

DISTRIBUTION oPE

COPY 1. ASSIGN COPY NO. TO HARD COPIES ONLY. A+

NO. 2. LIST MICROFICHE AND ABFTRACT RECIPIENTS LAST. t,3. EXTERNAL COPIES. INDICATE TRANSMITTER 44,4. CIRCLE COPY NO. OF REPCRTS ALREADY DISTRIBUTED. J%

47 Prof. D. Adams, U. Wyoming via Sandorff x x

48 Prof. T. Pian, M.I.T., via Sandorff x X1

49 Prof. S. W. Tsai, Washington U. via Sandorff x x

50 J. C. Halpin, AFML x x

51 J.A. Bailie, LMSC 81-12/154/1 x x

52 G. E. Bowle_ 7-70/229/2 x x

II

I

I

II I

[__ _ _

1KM~~

I W L 4 ''."' ' "'- '- .. ,,