ASTM D 1004 -  Standard Test Method for Tear Resistance (Graves Tear) of Plastic Film and Sheeting

Standard

This standard covers the tear resistance testing of flexible plastic film and sheeting.The specimen geometry of this test method produces a stress concentration (weak point) in a small area of the specimen. 

ASTM D 1004 - Fig. 1 Die for Tear Test Specimen

5. Significance and Use

5.1 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. Experience has shown the test to have its best reliability for materials which do not have brittle failure or do not elongate greater than two hundred percent during testing. 

Test Apparatus

In ASTM D 1004 Section 6.Apparatus the standard goes into detail of the machines and parts used for testing and measurement. A testing machine of the constant rate of crosshead-movement (UTM).

 6.1.3. Grips - Prefably, a set of self-aligning grips for holding the test specimen... The grips should minimize both slippage and uneven stress distribution.

Eccentric roller grips used in tear resistance testing