Influence of stacking angle of carbon fibers on fracture behavior of TiNi fiber impregnated CFRP composites

TiNi/CFRP composites have been fabricated by hot-pressing at a temperature of 180 °C. The CFRP layers were stacked with the carbon fibers at angles of 0°, 30°, 60° or 90° relative to the tensile direction. The fracture behavior was studied using notched specimens, which act as one-dimensional AE sources during tensile testing, to determine the fracture mode of the composites. Detection of strong Lamb waves shows that fracture in TiNi/CFRP composites with a 0° stacking configuration is mostly due to fiber breakage, which accounts for the high tensile strength of this configuration. In contrast, specimens with high stacking angles mainly fail by matrix cracking, with the production of weak Lamb waves, resulting in lower tensile strengths.