{{Short description|Materials engineering measurement}} {{Use dmy dates|date=May 2026}} '''Tear resistance''' (or '''tear strength''') is a measure of how well a material can withstand the effects of tearing.<ref>NAHAD GLOSSARY, http://www.nahad.org/aws/NAHAD/pt/sp/hsi_glossaries, 15 June 2012</ref> It is a useful engineering measurement for a wide variety of materials by many different test methods.
==Discussion== 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.<ref name=RLHudson>Tear Resistance., {{cite web |url=http://www.rlhudson.com/O-Ring%20Book/selecting-physical6.html |title=Physical Properties: Tear Resistance |accessdate=2012-06-15 |url-status=dead |archiveurl=https://web.archive.org/web/20120525103424/http://www.rlhudson.com/O-Ring%20Book/selecting-physical6.html |archivedate=25 May 2012 |df=dmy-all }}, 15 June 2012</ref> 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.<ref name=RLHudson />
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).<ref name=RLHudson />
==Tear resistance of different materials== Substances with high tear resistance include epichlorohydrin, natural rubber and polyurethane. In contrast, materials such as silicone and fluorosilicone have low tear resistance.<ref name=RLHudson />
==Tear-yield ratio== The ratio of tear resistance to the yield strength is called the tear-yield ratio. It is a measure of notch toughness.<ref>{{cite book | title=Fracture Resistance of Aluminum Alloys: Notch Toughness, Tear Resistance | publisher=ASM International | author=John Gilbert Kaufman | year=2001 | pages=38 | url=https://books.google.com/books?id=nd9_99j0oioC&dq=intitle%3ATear%253intitle%3Aresistance&pg=PA38 | isbn=9780871707321}} </ref>
==Standards by ASTM International== *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== *Landfill liner properties - tear resistance *Tearing energy *Fracture mechanics
==References== {{Reflist}}
== External links == * [https://web.archive.org/web/20121010021352/http://www.rlhudson.com/O-Ring%20Book/selecting-physical6.html Tear resistance on rlhudson.com]
Category:Solid mechanics Category:Deformation (mechanics)
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