The tearing strength of fabrics, papers, plastic films, or other similar materials in sheet form is determined by measurement of work done in tearing through a fixed length of the test specimen using the Elmendorf tear tester.

The Elmendorf Tear Tester consists of a brass sector pendulum pivoted on low-friction ball bearings over a vertical bracket fixed on a rigid metallic base. The test specimen, in shape of a rectangle, is held between two clamps, one of which is mounted on the pendulum and the other is mounted on the vertical bracket. The clamps are mounted in such a manner that their holding faces are aligned with each other when the pendulum is locked in its raised position. The pendulum is released by lifting a release lever. This action causes the pendulum to fall down under its weight and to tear the test specimen while doing so. The energy absorbed during tearing is indicated on a scale fitted on the pendulum by a low friction pointer pivoted on the axis of the pendulum.

Technical details