An experimental approach is presented to acquire the shear strength on the transversely isotropic plane of thick composites. Among various shear test methods of thick composites, the shear test by slotted shear specimen is a good method to cause the shear failure mode in the shear test section.
The optimal configurations of slotted shear specimen is obtained through finite element stress analysis by parametric studies on the length of test section and the specimen thickness. FEM results exhibit that there is a region of uniform and maximum shear stress in the test section except notch tips when the ratio of the test section length and the specimen thickness is about the same.
Although the test specimen is subject to high compressive stress concentration at the tips of the two notches, this is not a major problem since the compressive strength is an order of magnitude greater than the shear strength. The tensile stresses developed along the line joining the two notch roots are, however, a critical problem. The fixed sides boundary condition is applied to eliminate this tensile stress along the test section in stress analysis. Likely, the compressive supporter is used to eliminate this tensile stress along the test section in the shear test. This shear test method provide a region of uniform shear stress and the test section is one of maximum shear stress relative to all other regions of this specimen.
Therefore, this shear test method by slotted shear specimen is a potential method to obtain the shear strength on the transversly isotropic plane of thick composites.
