Elmendorf Tear Tester (patented product), A computer controlled falling-pendulum instrument, to determine the ballistic tearing strength of textiles, plastics, paper or board.

It enables rapid determination of the dynamic resistance of materials designed to be subjected to strong shearing loads (e.g. fabrics) or liable to be damaged by sharp or heavy objects (e.g. paper bags). Subsequently, the test was naturally adopted for all materials in the form of sheet or films, cardboards, cloth, knitted fabrics, plastic films, aluminum foil, non-woven fabrics, complex flexible packaging etc. But does not apply to sparse fabric or stretch materials which tearing direction might be shift in test.

Compressed air of 0.4~ 0.7 Mpa is required.

Procedure

The test is carried out on a specimen composed of one or more sheets of standard dimensions 100 x 63 mm, a crack in length of 20 mm of specimen is notched automatically, a usually with a distance of 43mm (1.7 in) remaining to be torn after initiating the tear. The energy of a pendulum of suitable weight is used to completely tear the specimen. The difference in the angle from the vertical of the center of gravity of the pendulum between the downswing and upswing is a measure of the energy absorbed in tearing the sample. This angular movement is measured with a digital encoder and is immediately converted to the mean tearing force for a single sheet by the microprocessor and software incorporated in the apparatus