An ILSS bending test fixture is used to determine the apparent interlaminar shear strength (ILSS). The test fixture is used for testing according to various standards on short, long and continuous fibre-reinforced plastics with thermoplastic or thermosetting base materials and is used for unidirectional layers or fabrics. In addition, isotropic materials such as pure resin or adhesive resin materials can also be tested with this test fixture.

The short beam test method is a modification of the 3-point bending test. The support distance is small in relation to the specimen thickness, which means that the specimen is loaded in shear. The specimens specified in the relevant standards differ in length, thickness and support span. The test specimen is a short beam made of a thermoplastic or thermosetting matrix with fibre reinforcement in 0° or 0°/90° direction. By apparent interlaminar shear strength the standard means “the maximum shear stress present in half the thickness of the test specimen at the moment of first failure”.