Post on 12-Jul-2015
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)
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2011 SPE ANTEC Vinyl Division
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)
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2011 SPE ANTEC Vinyl Division
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
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2011 SPE ANTEC Vinyl Division
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
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2011 SPE ANTEC Vinyl Division
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
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2011 SPE ANTEC Vinyl Division
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
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2011 SPE ANTEC Vinyl Division
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
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2011 SPE ANTEC Vinyl Division
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
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2011 SPE ANTEC Vinyl Division
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
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2011 SPE ANTEC Vinyl Division
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
– 7% variation achieved with 0.91kg tup and 1.59cm probe
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2011 SPE ANTEC Vinyl Division
Ratio of Probe to Support Ring Analysis
• 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)
Support Ring diameter : Probe Diameter
MFE of Material 2
3.63kg tup
1.82kg tup
0.91kg tup
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2011 SPE ANTEC Vinyl Division
Material 3 Results
• Similar trend observed
– 23% variation achieved with 0.91kg tup and 1.27cm probe
– 13% variation achieved with 0.91kg tup and 1.59cm probe
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2011 SPE ANTEC Vinyl Division
Ratio of Probe to Support Ring Analysis
• 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)
Support Ring diameter : Probe Diameter
MFE of Material 3
3.63kg tup
1.82kg tup
0.91kg tup
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2011 SPE ANTEC Vinyl Division
Comparison of Impact Section
• Based on thousands of impact events, section two (bottom) always
exhibited lower MFE values for each material
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2011 SPE ANTEC Vinyl Division
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
– 1.59cm probe diameter
– 3.81cm support ring diameter
– Ratio of 2.4:1
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2011 SPE ANTEC Vinyl Division
Conclusions /2
• Based on entire sample population:
• Most repeatable test setup (highest precision):
– 3.63kg tup
– 1.27cm probe diameter
– 6.35cm support ring diameter
– 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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2011 SPE ANTEC Vinyl Division
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
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2011 SPE ANTEC Vinyl Division
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
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2011 SPE ANTEC Vinyl Division
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
2011 SPE ANTEC Vinyl Division
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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
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2011 SPE ANTEC Vinyl Division