Ballistic perforation of thin, plain woven composites is a dynamic, high-strain-rate process. Damage mechanics occur through multiple length scales including microscale damage to fiber and fiber-matrix interface, mesoscale damage to fiber tows, tow-tow interface, and matrix, and macroscale damage across tows, matrix, and laminas. Capturing and validating the mesoscale damage mechanisms inherent in this process using a computational model requires a systematic approach, building up the complexity of the model. Quasi-static punch-shear mechanical testing of composites has been shown to approximate many of the energy dissipating mechanisms of dynamic impact of composite targets while removing the added complexity of the high-strain-rate variable. Thus, quasi-static punch-shear may be used as an intermediate step in the process of building up model complexity with the final goal of modeling ballistic perforation.
In this work, quasi-static punch-shear testing of a single layer, plain weave S-2 glass/SC15 composite is performed. Eight composite panels with two different support spans are tested separately in a load-unload cycle. Load levels include approximately 1/4, 1/2, and 3/4 of failure and full failure load. Post-test specimens at four punch-shear induced damage states are examined by high-resolution optical photography to qualify the damage at each load level. Mesoscale damage mechanisms are reported for each load level. Finally, the load-displacement curves are correlated to progressively increasing damage states to quantify the energy dissipated by the mesoscale damage mechanisms observed.