Information on the most widely used ASTM standards within the materials testing industry
ASTM D1004: Standard Test Method for Tear Resistance (Graves Tear) of Plastic Film and Sheeting
ASTM D1004 is a test method that determines the tear strength of flexible plastic film and sheeting at very low rates of loading using a constant-rate-of crosshead-movement type tensile testing machine. Tearing is produced in a small area of stress concentration of the plastic film or sheeting specimen at controlled speeds below the rate encountered in real world applications in order to produce the most reliable data, which can be used to compare and analyze the tear resistance. Actual use of performance in tearing of certain plastics may not necessarily corralate with the data acquired from this test method. The specimen geometry of this test method produces a stress concentration in a small area of the specimen. The maximum stress, usually found near the onset of tearing, is recorded as the tear resistance in newtons (or pounds-force). The method is not applicable for film or sheeting material where brittle failures occur during testing or where maximum extension is greater than 101.6 mm (4 in.).

Scope:
Tear resistance measures the ultimate force required to tear film or sheet. It is often used for quality control checks or for material comparison where tear failures are possible.
Test Procedure:
The average thickness of the specimen is measured. The specimen is then placed in the grips of the testing machine and pulled at a rate of 2 in. per minute until rupture.
Specimen Size:
The specimen is die cut to the appropriate shape from a sheet. The shape of the specimen is designed to create a tear when the specimen is pulled in tension. Die C specimens are commonly used.

Tear test for film and thin plastic
Plastic films are used in many applications, including packaging, consumer goods, construction, transportation, and medical. Tear resistance is one of the properties that makes plastic films strong. It turns out that the durability of the material is crucial if it is subjected to a tear event. When testing the tensile strength of a film, tensile modulus and tear resistance are often used in combination to provide comprehensive information about its strength.
The force to initiate tearing across a specific geometry of a film or sheeting specimen is measured using a constant rate of grip separation universal test machine, such as those listed below. The force necessary to initiate a tear is calculated from the resulting load-time or load-displacement data.
Tear resistance of plastic film or sheeting is a complex function of its ultimate resistance to rupture. The specimen geometry and speed of testing in this test method are controlled to produce tearing in a small area of stress concentration at rates far below those usually encountered in service. The test has its best utility and reliability for materials that do not have brittle failure or do not elongate greater than two hundred percent during testing.
Data from this test method are comparable only from specimens that vary no more than +/-10% from the nominal or average thickness of all specimens tested. And so the tearing resistance is expressed in maximum N (lbf) of force to tear the specimen.
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