The Picture Frame Shear Test Fixture in its various forms has been around for many years. It was originally developed as an in-plane shear test method for solid laminated materials such as plywood and composite laminates. More recently it has increasingly been also used for in-plane testing of sandwich panels of all types, including honeycomb and foam core constructions with laminated composite or metal facesheets. And currently it is finding use as a drapeability test for both dry fabrics and preimpregnated fiber materials, in both continuous fiber and woven fabric forms. 

Formal standards for these tests and test methods have not existed, with a wide range of fixture configurations being developed over the years. However, the basic principle is that a square specimen is gripped along all four edges by four pair of clamps that are pin-connected at their ends to form a square frame into which the specimen is clamped. An axial load is applied at two diagonal corners to induce the shear loading. A tensile loading is typically used, to avoid buckling of the frame. The first standard defining the Picture Frame Shear Test Method has recently been introduced by ASTM, as ASTM D8067 (Reference 1). The fixture is shown in Fig. 1.