Tear resistance (or tear strength) is a measure of how well a material can withstand the effects of

tearing Tearing is the act of breaking apart a material by force, without the aid of a cutting tool. A tear in a piece of paper, fabric, or some other similar object may be the result of the intentional effort with one's bare hands, or be accidental. ...

. It is a useful engineering measurement for a wide variety of materials by many different

test method A test method is a method for a test in science or engineering, such as a physical test, chemical test, or statistical test. It is a specified procedure that produces a test result. To ensure accurate and relevant results, a test method should b ...

Discussion

For example, with

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Types of polyisoprene ...

, tear resistance measures how the test specimen resists the growth of any cuts when under tension, it is usually expressed in kN/ m.Tear Resistance., , 15 June 2012 Tear resistance can be gauged via the same ASTM D 412 apparatus used to measure

tensile strength Ultimate tensile strength (also called UTS, tensile strength, TS, ultimate strength or F_\text in notation) is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials, the ultimate ...

, 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 A uniform is a variety of costume worn by members of an organization while usually participating in that organization's activity. Modern uniforms are most often worn by armed forces and paramilitary organizations such as police, emergency serv ...

pulling

force In physics, a force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the Magnitu ...

applied until the aforementioned deformation occurs. Tear resistance is then calculated by dividing the force applied by the thickness of the material. 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).

Tear resistance of different materials

Substances with high tear resistance include epichlorohydrin,

natural rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Types of polyisoprene ...

and

polyurethane Polyurethane (; often abbreviated PUR and PU) is a class of polymers composed of organic chemistry, organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane term ...

. In contrast, materials such as

silicone In Organosilicon chemistry, organosilicon and polymer chemistry, a silicone or polysiloxane is a polymer composed of repeating units of siloxane (, where R = Organyl group, organic group). They are typically colorless oils or elastomer, rubber ...

and fluorosilicone have low tear resistance.

Tear-yield ratio

The ratio of tear resistance to the

yield strength In materials science and engineering, the yield point is the point on a stress–strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Below the yield point, a material will deform elastically and w ...

is called the tear-yield ratio. It is a measure of notch toughness.

Standards by
ASTM International ASTM International, formerly known as American Society for Testing and Materials, is a standards organization that develops and publishes voluntary consensus technical international standards for a wide range of materials, products, systems and s ...

*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

References

External links

Tear resistance on rlhudson.com
Solid mechanics Deformation (mechanics) {{materials-sci-stub