Determination of core shear properties of threedimensional woven sandwich composites

The core shear characteristics of a relatively new material have been investigated by two methods: three point bending tests and a shear test. The material is based on woven sandwich fabric preform, which offers important advantages related to the integral core-skin structure. The core shear moduli results from the block shear test and ASTM three point bending tests show very little difference. The results from the shear test obtained by measuring the crosshead displacement were verified by conducting additional shear tests, in which two linear variable differential transformers were used for strain measurement in the longitudinal and transverse directions. The ASTM block shear test and three point bending test were used to determine the core shear strength of the material. To obtain pure core shear failure leads to a correct core shear strength result; the three point bending test was modified by increasing the skin thickness and stiffness of the panel.