hamrock, jacobson and schmid©1998 mcgraw-hill chapter 3: solid materials iron is taken from the...

Hamrock, Jacobson and Schmid©1998 McGraw-Hill

Chapter 3: Solid Materials

Iron is taken from the earth and copper is smelted from ore.Man puts an end to the darkness;he searches the farthest recesses for ore in the darkness.The Bible (Job 28:2-3)

Image: Iron flows from a blast furnace. Source: American Iron and Steel Institute.


Ductile Tension Test Specimens

Figure 3.1 Ductile material from a standard tensile test apparatus. (a) Necking; (b) failure.

text reference: Figure 3.1, page 90


Brittle Tension Test Specimen

Figure 3.2 Failure of a brittle material from a standard tesile test apparatus.



Strength/Density Comparison

Figure 3.3 Strength/density for various materials.



Fiber Reinforced Composite

Figure 3.4 Cross section of fiber reinforced composite material.



Ductile - diagram

Figure 3.5 Stress-strain diagram for a ductile material.

text reference: Figure 3.5, , page 96


Yield Strength Definition

Figure 3.6 Typical stress-strain behavior for ductile metal showing elastic and plastic deformations and yield strength Sy.



Brittle and Ductile Metal Comparison

Figure 3.7 Typical tensile stress-strain diagrams for brittle and ductile metals loaded to fracture.



Stress-Strain Diagram for a Ceramic

Figure 3.8 Stress-strain diagram for a ceramic in tension and in compression.



Composite Bar

Figure 3.9 Bending strength of bar used in Example 3.6.



Stress-Strain Diagram for Polymers

Figure 3.10 Stress-strain diagram for polymer below, at, and above its glass transition temperature Tg.



Density of Various Materials

Figure 3.11 Density for various metals, polymers and ceramics at room temperature (20°C, 68°F) [From ESDU (1984)].



Density for Various

Materials

Material Dens ity, kg/m3 lbm/in3

MetalsAluminum and its alloysa

Aluminum tinBabbitt, lead-based white metalBabbitt, tin-based white metalBrassesBronze, aluminumBronze, leadedBronze, phosphor (cast)b

Bronze, porousCopperCopper leadIron, castIron, porousIron, wroughtMagnesium alloysSteelsc

Zinc Alloys

2.7 x 103

3.1 x 103

10.1 x 103

7.4 x 103

8.6 x 103

7.5 x 103

8.9 x 103

8.7 x 103

6.4 x 103

8.9 x 103

9.5 x 103

7.4 x 103

6.1 x 103

7.8 x 103

1.8 x 103

7.8 x 103

6.7 x 103

0.0970.110.360.270.310.270.320.310.230.320.340.270.220.28

0.0650.280.24

PolymersAcetal (polyformaldehyde)Nylons (polyamides)Polyethylene, high densityPhenol formaldehydeRubber, naturald

Rubber, silicone

1.4 x 103

1.14 x 103

0.95 x 103

1.3 x 103

1.0 x 103

1.8 x 103

0.0510.0410.0340.0470.0360.065

CeramicsAlumina (Al2O3)Graphite, high strengthSilicon carbide (SiC)Silicon nitride (Si3N4)

3.9 x 103

1.7 x 103

2.9 x 103

3.2 x 103

0.140.0610.100.12

aStructural alloysbBar stock typically 8.8 x 103 kg/m3 (0.03lbm/in3.)cExcluding “refractory” steelsd“Mechanical” rubber

Table 3.1 Density for various metals, polymers, and ceramics at room temperature (20°C; 68°F). [From ESDU (1984)]

text reference: Table 3.1, page 103


Elastic Modulus for Various Materials

Figure 3.12 Modulus of elasticity for various metals, polymers, and ceramics at room temperature (20°C, 68°F) [From ESDU (1984)].



Elastic Modulus for Various Materials

Material Modulus of Elasticity, EGPa Mpsi

MetalsAluminumAluminum alloysa

Aluminum tinBabbitt, lead-based white metalBabbitt, tin-based white metalBrassesBronze, aluminumBronze, leadedBronze, phosphorBronze, porousCopperIron, grey castIron, malleable castIron, spheroidal graphiteb

Iron, porousIron, wroughtMagnesium alloysSteel, low alloysSteel, medium and high alloysSteel, stainlessc

Steel, high speedZinc alloysd

62706329521001179711060124109170159801704119620019321250

9.010.29.14.27.514.517.014.116.08.718.015.824.723.111.624.75.928.429.028.030.77.3

PolymersAcetal (polyformaldehyde)Nylons (polyamides)Polyethylene, high densityPhenol formaldehydee

Rubber, naturalf

2.71.90.97.0

0.004

0.390.280.131.02

0.0006Ceramics

Alumina (Al2O3)GraphiteCemented carbidesSilicon carbide (SiC)Silicon nitride (Si3N4)

39027450450314

56.63.965.365.345.5

aStructural alloysbFor bearingscPrecipitation-hardened alloys up to 211 Gpa (30 Mpsi).dSome alloys up to 96 Gpa (14 Mpsi).eFilledf2.5%-carbon-black “mechanical” rubber.

Figure 3.12 Modulus of elasticity for various metals, polymers, and ceramics at room temperature (20°C; 68°F). [From ESDU (1984)]



Poisson’s Ratio for Various Materials

Table 3.3 Poisson’s ratio for various metals, polymers, and ceramics at room temperature (20°C; 68°F). [From ESDU (1984)]


Material Poisson’s ratio, Metals

Aluminum and its alloysa

Aluminum tinBabbitt, lead-based white metalBabbitt, tin-based white metalBrassesBronzeBronze, porousCopperCopper leadIron, castIron, porousIron, wroughtMagnesium alloysSteelsZinc alloys

0.33---------

0.330.330.220.33---

0.260.200.300.330.300.27


Rubber

---0.400.35---

0.50Ceramics

Alumina (Al2O3)Graphite, high strengthCemented carbidesSilicon carbide (SiC)Silicon nitride (Si3N4)

0.28---

0.190.190.26

aStructural alloys


Thermal Condictivity for Various Materials

Figure 3.13 Thermal conductivity for various metals, polymers, and ceramics at room temperature (20°C, 68°F). [From ESDU (1984)].



Thermal Conductivity for Various Materials

Material Thermal Conductivity, K tW/m-°C Btu/ft-hr°F

MetalsAluminumAluminum alloys, casta

Aluminum alloys, siliconb

Aluminum alloys, wroughtc

Aluminum tinBabbitt, lead-based white metalBabbitt, tin-based white metalBrassesa

Bronze, aluminuma

Bronze, leadedBronze, phosphor (cast)d

Bronze, porousCoppera

Copper leadIron, grey castIron, spheroidal graphiteIron, porousIron, wroughtMagnesium alloysSteel, low alloyse

Steel, mediumSteel, stainlessf

Zinc alloys

2091461701511802456120504750301703050302870110353015110

120849887

100143269292729179817291716406420178.764


Rubber, naturalf

0.240.250.5---1.6

0.140.140.29---

0.92Ceramics

Alumina (Al2O3)g

Graphite, high strengthSilicon carbide (SiC)Silicon nitride (Si3N4)

2512515---

14728.6---

aAt 100°CbAt 100°C (~150 W/m-°C at 25°C)c20 to 100°CdBar stock typically 69 W/m-°Ce20 to 200°CfTypically 22W/m-°C at 200°CgTypically 12W/m-°C at 400°C

Table 3.4 Thermal conductivity for various metals, polymers, and ceramics at room temperature (20°C; 68°F). [From ESDU(1984)]



Thermal Expansion Coefficient for

Various Materials

Figure 3.14 Linear thermal expansion coefficient for various metals, polymers, and ceramics applied over temperature range 20 to 200°C (68 to 392°F) [From ESDU (1984)].



Linear Thermal Expansion

Coefficient for Various Materials

Material Linear Thermal ExpansionCoefficient, a

(°C) -1 (°F) -1

MetalsAluminumAluminum alloysa

Aluminum tinBabbitt, lead-based white metalBabbitt, tin-based white metalBrassesBronzesCopperCopper leadIron, castIron, porousIron, wroughtMagnesium alloysSteel, alloyb

Steel, stainlessSteel, high speedZinc alloys

23 x 10-6

24 x 10-6

24 x 10-6

20 x 10-6

23 x 10-6

19 x 10-6

18 x 10-6

18 x 10-6

18 x 10-6

11 x 10-6

12 x 10-6

12 x 10-6

27 x 10-6

11 x 10-6

17 x 10-6

11 x 10-6

27 x 10-6

12.8 x 10-6

13.3 x 10-6

13.3 x 10-6

11 x 10-6

13 x 10-6

10.6 x 10-6

10.0 x 10-6

10.0 x 10-6

10.0 x 10-6

6.1 x 10-6

6.7 x 10-6

6.7 x 10-6

15 x 10-6

6.1 x 10-6

9.5 x 10-6

6.1 x 10-6

15 x 10-6

PolymersThermoplasticsc

Thermosetsd

Acetal (polyformaldehyde)Nylons (polyamides)Polyethylene, high densityPhenol formaldehydee

Rubber, naturalf

Rubber, nitrileg

Rubber, silicone

(60-100) x 10-6(10-80) x 10-6

90 x 10-6

100 x 10-6

126 x 10-6

(25-40) x 10-6

(80-120) x 10-6

34 x 10-6

57 x 10-6

(33-56) x 10-6

(6-44) x 10-6

50 x 10-6

56 x 10-6

70 x 10-6

(14-22) x 10-6

(44-67) x 10-6

62 x 10-6

103 x 10-6

CeramicsAlumina (Al2O3)

h

Graphite, high strengthSilicon carbide (SiC)Silicon nitride (Si3N4)

5.0 x 10-6

1.4-4.0 x 10-6

4.3 x 10-6

3.2 x 10-6

2.8 x 10-6

0.8-2.2 x 10-6

2.4 x 10-6

1.8 x 10-6

aStructural alloysbCast alloys can be up to 15 x 10-6/(°C)cTypical bearing materialsd25 x 10-6(°C)-1 to 80 x 10-6(°C)-1 when reinforcedeMineral filledfFillers can reduce coefficientsgVaries with compositionh0 to 200°C

Table 3.5 Linear thermal expansion coefficient for various metals, polymers and ceramics at room temperature (20°C; 68°F). [From ESDU (1984)]



Specfic Heat Capacity for

Various Materials

Figure 3.15 Specific heat capacity for various metals, polymers, and ceramics at room temperature (20°C; 68°F) [From ESDU (1984)].



Specific Heat Capacity for Various MaterialsMaterial Specific Heat Capacity, Cp

kJ/kg-°C Btu/lb°FMetals

Aluminum and its alloysAluminum tinBabbitt, lead-based white metalBabbitt, tin-based white metalBrassesBronzesCoppera

Copper leadIron, castIron, porousIron, wroughtMagnesium alloysSteelsb

Zinc alloys

0.90.960.150.210.390.380.380.320.420.460.461.00.450.4

0.220.23

0.0360.05

0.0930.0910.0910.0760.100.110.110.240.11

0.096Polymers

ThermoplasticsThermosetsRubber, natural

1.4---2.0

0.33---

0.48Ceramics

Alumina (Al2O3)h

GraphiteCemented CarbidesSilicon carbide (SiC)Silicon nitride (Si3N4)

---0.80.7------

---0.20.17------

aAluminum bronze up to 0.48 kJ/kg-°C (0.12 Btu/lbm-°F)bRising to 0.55 kJ/kg-°C (0.13 Btu/lbm-°F) at 200°C (392 °F)

Table 3.6 Specific heat capacity for various metals, polymer, and ceramics at room temperature (20°C; 68°F). [From ESDU (1984)]



Rigid Beam Assembly

Figure 3.16 Rigid beam assembly used in Example 3.12.



Figure 3.17 Modulus of Elasticity plotted against density. The heavy envelopes enclose data for a given class of material. The diagonal contours show the longitudinal wave velocity. The guidelines of constant E/, E1/2/ , and E1/3/ allow selection of materials for minimum weight, deflection-limited design. [From Ashby (1992)].


Elastic Modulus vs.

Density


Material ClassesClass Members Short nameEnginering alloys

(the metals and alloys ofengineering)

Aluminum alloysCopper alloysLead alloysMagnesium alloysMolybdenum alloysNickel alloysSteelsTin alloysTitanium alloysTungsten alloysZinc alloys

Al alloysCu alloysLead alloysMg alloysMo alloysNi alloysSteelsTin alloysTi alloysW alloysZn alloys

Engineering polymers(the thermoplastics andthermosets of engineering)

EpoxiesMelaminesPolycarbonatePolyesterPolyethylene, high densityPolyethylene, low densityPolyformaldehydePolymethylmethacrylatePolypropylenePolytetrafluoroethylenePolyvinyl chloride

EPMELPCPESTHDPELDPEPFPMMAPPPTFEPVC

Engineering ceramics(fine ceramics capable ofload-bearing application)

AluminaDiamondSialonsSilicon carbideSilicon nitrideZirconia

Al2O3CSialonsSiCSi3N4ZrO2

Table 3.7 Material classes and members and short names of each member. [From Ashby (1992)].



Material Classes (cont.)

Table 3.7 Material classes and members and short names of each member. [From Ashby (1992)].

Class Members Short nameEngineering composites

(the composites ofengineering practice) Adistinction is drawnbetween the properties of aply (uniply) and a laminate(laminates)

Carbon-fiber reinforcedpolymerGlass-fiber reinforcedpolymerKevlar-fiber reinforcedpolymer

CFRP

GFRP

KFRP

Porous ceramics(traditional ceramics,cements, rocks, andminerals

BrickCementCommon rocksConcretePorcelainPottery

BrickCementRocksConcretePclnPot

Glasses(ordinary silicate glass)

Borosilicate glassSoda glassSilica

B-glassNa-glassSiO2

WoodsSeparate clusters describeproperties parallel to thegrain and normal to it andwood products

AshBalsaFirOakPineWood products (ply, etc.)

AshBalsaFirOakPineWood products

Elastomers(natural and artificialrubbers)

Natural rubberHard butyl rubberPolyurethanesSilicone rubberSoft butyl rubber

RubberHard butylPUSiliconeSoft butyl

Polymer foams(foamed polymers ofengineering)

CorkPolyesterPolystyrenePolyurethane

CorkPESTPSPU



Strength vs. Density

Figure 3.18 Strength plotted against density (yield strength for metals and polymers, compressive strength for ceramics, tear strength for elastomers, and tensile strength for composites). The guidelines of S/, S2/3/, and S1/2/ allow selection of materials for minimum-weight, yield-limited design. [From Ashby (1992)].



Elastic Modulus

vs. Strength

Figure 3.19 Modulus of elasticity plotted against strength. The design guidelines help with the selection of materials for such machine elements as springs, knife-edges, diaphragms, and hinges. [From Ashby (1992)].



Wear Constant

vs. Limiting Pressure

Figure 3.20 Archard wear constant plotted against limiting pressure. [From Ashby (1992)].



Elastic Modulus vs.

Cost x Density

Figure 3.21 Modulus of elasticity plotted against cost times density. The reference lines help with selection of materials for machine elements. [From Ashby (1992)].


hamrock, jacobson and schmid©1998 mcgraw-hill chapter 3: solid materials iron is taken from the...

Documents