The Elmendorf Tear Test, also known as Elmendorf tear strength, is a method used to determine the force required to tear a fabric in a single pass. It is typically performed using an Elmendorf Tearing Tester or a falling hammer-type instrument. Here are the key details about this test:

• Scope: The test measures the force value needed to tear a fabric, plastic film, or thin sheeting. It helps evaluate the tear resistance of materials, especially those used in packaging. Depending on the application, either a low or high propagation force may be desirable.
• Procedure:
  • Ten samples are cut from the material, both in the machine direction and the transverse direction.
  • A sample is positioned in the tester and clamped in place.
  • A cutting knife creates a slit in the sample, ending 43 mm from the far edge.
  • The pendulum is released to propagate the slit through the remaining 43 mm.
  • The energy loss by the pendulum is used to calculate an average tearing force.
• Sample Sizes:
  • The preferred test sample for plastic films is the constant radius sample, which provides a constant radius from the start of the tear strength measurement. This is useful for materials where the tear may not propagate directly up the sample as intended.
  • Another common sample shape is a 63 mm x 76 mm rectangle.
  • For textiles, a modified rectangle adds height on the ends of the sample to minimize unraveling of the outside edges.

The results of the Elmendorf Tear Test are presented as tearing force in milli-newtons (or grams-force). Keep in mind that there is no direct relationship between thickness and tearing force, so comparisons should only be made for samples of the same thickness. If you’re curious about material durability, this test provides valuable insights!

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