the effect of testing parameters on the functional impact resistance of upvc commercial products

The Effect of Testing Parameters on the

Functional Impact Resistance of UPVC

Commercial Products

Akshay Agarwal

Joshua Anthony

Liam Driscoll

2011 SPE ANTEC Vinyl Division

Abstract

• Advancements in technology have expanded the range of acceptable testing methods

• Accuracy* of these methods needs to be determined

*Repeatability within a lab and reproducibility

among labs

• Research focused on the effect of changing testing parameters for the falling dart impact test (Gardner Impact Test - ASTM D5420)

2


Advantages of Gardner

Impact Test

• Minimal cost

• Ease-of-use

• Commingled effect of material of

choice, design, processing, and assembly

variables

• Realistic geometries, testing environment, and

end-use impacting speeds (strain rates)

3


References

• Nunnery – ANTEC 1993 – Questioned the value and relevance of conventional Izod testing and HDT

• Lavach – ANTEC 1998 – Concluded that the mass of the base of the testing unit affects the variation in regards to the MFE

• Lutz & Goldman – ANTEC 1979 –Investigated modified falling weight tests to qualify low temperature, impact resistant PVC

4


References

• Tryson, Takemori, and Yee – 1979 – Investigated

the effect of specimen geometry and plunger

radius of ductile and brittle materials

• Sabbagh & Marchand – ANTEC 2003 –

Investigated the ductile to brittle transition

temperature in relation to quality control

• Driscoll – ASTM STP (HOUSTON 1985) –

Instrumented Impact Testing of Plastics and

Composite Materials

5


Research Parameters

• One standard rigid vinyl formulation

• Three Samples

– Two colors (white vs. tan)

– Two textures (smooth vs. texture)

• Two surface sections

• Two probe diameters (O.D.)

• Four support rings (I.D.)

• Three tup weights

• Total of 144 test conditions

6


Research Parameters

D3763 D4226 D5420Research Parameters

at UML

Probe Diameter

(cm)1.27 1.27 1.27 1.27, 1.59

Support Ring

Diameter (cm)7.62 1.63 7.62 1.63, 3.81, 5.08, 6.35

Weight (kg) Variable 3.6 0.9, 1.8, 3.6 3.63, 1.82, 0.91

7


Protocol

• The following series of slides illustrates the

effect of probe diameter (O.D.) against varying

support rings (I.D.) and tup weights for the

material candidates

8


Material 1 Results

• The 0.91kg tup produced higher MFE variation

– Proportional to the support ring diameter

– 23% variation achieved with 1.27cm probe

– 6% variation achieved with 1.59cm probe

9


Ratio of Probe to Support Ring Analysis

• Testing conditions having a ratio of 4:1 produced very similar

values for the 0.91kg tup regardless of rate dependency

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

MF

E (

J)

Support Ring diameter : Probe Diameter

MFE of Material 1

3.63kg tup

1.82kg tup

0.91kg tup

10


Material 2 Results

• Variability directly related to interaction between the tup weight and support ring diameter

• Greater reliability with greater weights across the range of support ring diameters

– 17% variation achieved with 0.91kg tup and 1.27cm probe


11



• At the ratio of 4:1 the difference between material 1 and 2 can be

attributed to texture and rate dependency

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

MF

E (

J)


MFE of Material 2

3.63kg tup

1.82kg tup

0.91kg tup

12


Material 3 Results

• Similar trend observed



13



• Overall, lower MFE variability using 3.63kg tup and greater

variability using the 0.91kg tup (more rate dependent)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

MF

E (

J)


MFE of Material 3

3.63kg tup

1.82kg tup

0.91kg tup

14


Comparison of Impact Section

• Based on thousands of impact events, section two (bottom) always

exhibited lower MFE values for each material

15


Conclusions /1

• Based on entire sample population:

• Least reliable test setup (high bias/fair precision):

– 0.91kg tup

– 1.27cm probe diameter

– 6.35cm support ring diameter

– Ratio of 5:1

• Most reliable test setup (low bias/fair precision):

– 1.82kg tup



– Ratio of 2.4:1

16


Conclusions /2

• Based on entire sample population:

• Most repeatable test setup (highest precision):

– 3.63kg tup



– Ratio of 5:1

Rate Dependency on MFH

Tup Weight (kg) Mean Failure Height (cm) Impacting Velocity (cm/s)

3.63 21.7 206.4

1.82 44.2 294.5

0.91 85.7 409.8

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Conclusions /3

• Single laboratory analysis equals repeatability

• No attempt to investigate multi-laboratory

reliability

• The 1.27cm appears to be the most biased

probe diameter…however, this is the preferred

geometry in all three ASTM protocols

• Lower weight tup (0.91kg) produced higher

variability across support ring diameters

18


Goldman and Lutz Revisited

• Following the protocol reported in the 1979

ANTEC paper (“scratched product”), a further

investigation of “Pre- and Post-installed

product” using the “UML Protocol” showed

dramatic changes in impact behavior

19


Control Scratch Control

Average Mean

Failure Energy (J)

Standard

Deviation (J)

Average Mean

Failure Energy (J)

Standard

Deviation (J)

Material 1 10.6 0.15 2.6 0.16

Material 2 12.2 0.15 2.7 0.12

Material 3 11.2 0.15 2.5 0.11

Comparison Between Testing

Methods• Minimal standard deviation for 100 events

• In comparison, the MFEs are statistically

equivalent


20

ASTM Method

(25 Events)

Method Based

on 25 Failures

Method Based

on 100 Failures

Mean Failure

Energy (J) 13.72 14.17 14.20

In Conclusion

• This was a limited undergraduate research

project and that more work would be

helpful

• We would greatly appreciate your

suggestions on additional areas to

investigate in order to improve the value of

this work

• Thank you

21


the effect of testing parameters on the functional impact resistance of upvc commercial products

Technology

hdtlavach antec

effect of testing parameters

mfelutz goldman antec

testing environment

testing unit

effect of probe diameter

support ring diameter23

support ring diameter