Picture Frame Test According To DIN SPEC 4885 / DIN EN ISO 20337

The shear test using DIN SPEC 4885 / DIN EN ISO 20337 is a picture frame shear test. Laminates with thermosetting or thermoplastic matrices reinforced with fibres in 0°- or 0°/90°-direction can be tested. The square shaped specimen is built symmetrically and balanced around the midplane. Typically the thickness of the specimen is 2…4 mm.

It requires expensive test fixtures and significant amounts of test material, as opposed to the established tests. But it provides great advantages:

  • Shear strenght can be monitored in the linear as well as non-linear range of load-deformation-behaviour for shear deformations (slidings) larger than 5 %. For the first time, maximum shear strenght even in this range can be determined.
  • The all-side clampings prevent free rims and thus prevent load shifting effects.
  • The results thereby show small variance usually less than 3 %, which makes the method suitable for parameter studies or quality check.
  • The single layers of the specimen exclusively see pure shear stress. It is distributed sufficiently homogenous over the specimen. The maximum shear stress is located in the center which typically is the location of failure.

For the shear test using DIN SPEC 4885 / DIN EN ISO 20337 we developed the shear frame test fixture GZ S-100 / GZ S-100 HT. Hydraulic clampings provide quick and easy change of specimen. The testing routine takes only few minutes, so it can be integrated into industrial environments for shear tests series.