ASTM D3846 describes the method for determining the inplane shear strength of reinforced plastic composite materials. These specimens are typically thermosetting plastics with reinforcements that widely vary in type and thickness ranging from 2.54 mm to 6.60 mm.
The test method is similar to that of ASTM D695, Test Method for Compressive Properties of Rigid Plastics, except that in the ASTM D3846 method, failure of the specimen occurs in shear between two centrally located notches that are machined halfway through the thickness of the specimen and spaced a fixed distance apart on opposing faces. The same compression fixture is used in both methods and placed between two hardened steel
compression platens. Due to the high compressive forces expected, we usually recommend a
dual column electromechanical test frame configured with
Bluehill® software for this application.