Tear resistance
Tear resistance (or tear strength) is a measure of how well a material can withstand the effects of tearing.[1] It is a useful engineering measurement for a wide variety of materials by many different test methods.
Discussion
[edit]For example, with rubber, tear resistance measures how the test specimen resists the growth of any cuts when under tension, it is usually expressed in kN/m.[2] Tear resistance can be gauged via the same ASTM D 412 apparatus used to measure tensile strength, modulus and elongation. ASTM D 624 can be applied to measure the resistance to the formation of a tear (tear initiation) and the resistance to the expansion of a tear (tear propagation). Regardless of which of these two is being measured, the sample is held between two holders and a uniform pulling force applied until the aforementioned deformation occurs. Tear resistance is then calculated by dividing the force applied by the thickness of the material.[2]
Materials with low tear resistance sometimes have poor resistance to abrasion and when damaged will quickly fail (this includes hard materials, since hardness is not related to tear resistance).[2]
Tear resistance of different materials
[edit]Substances with high tear resistance include epichlorohydrin, natural rubber and polyurethane. In contrast, materials such as silicone and fluorosilicone have low tear resistance.[2]
Tear-yield ratio
[edit]The ratio of tear resistance to the yield strength is called the tear-yield ratio. It is a measure of notch toughness.[3]
Standards by ASTM International
[edit]- C1681-14 Standard Test Method for Evaluating the Tear Resistance of a Sealant Under Constant Strain
- D1004-13 Standard Test Method for Tear Resistance (Graves Tear) of Plastic Film and Sheeting
- D1922-15 Standard Test Method for Propagation Tear Resistance of Plastic Film and Thin Sheeting by Pendulum Method
- D1938-14 Standard Test Method for Tear-Propagation Resistance (Trouser Tear) of Plastic Film and Thin Sheeting by a Single-Tear Method
- D2212-00(2015) Standard Test Method for Slit Tear Resistance of Leather
- D2582-16 Standard Test Method for Puncture-Propagation Tear Resistance of Plastic Film and Thin Sheeting
- D4932/D4932M-89(2014)e1 Standard Test Method for Fastener Rupture and Tear Resistance of Roofing and Waterproofing Sheets, Roll Roofing, and Shingles
- E604-15 Standard Test Method for Dynamic Tear Testing of Metallic Materials
See also
[edit]References
[edit]- ^ NAHAD GLOSSARY, http://www.nahad.org/aws/NAHAD/pt/sp/hsi_glossaries, 15 June 2012
- ^ a b c d Tear Resistance., "Physical Properties: Tear Resistance". Archived from the original on 25 May 2012. Retrieved 15 June 2012., 15 June 2012
- ^ John Gilbert Kaufman (2001). Fracture Resistance of Aluminum Alloys: Notch Toughness, Tear Resistance. ASM International. p. 38. ISBN 9780871707321.
External links
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