Modeling and experimental study on cure-induced residual stress in SMA-Reinforced CFRP composites

In recent years, superelastic shape memory alloys (SMA) have been incorporated into carbon fiber reinforced polymer (CFRP) composites to enhance their impact resistance. However, while SMA integration improves mechanical performance, it also introduces challenges such as increased curing stress and deformation. This study investigates the evolution of residual stress during curing and its impact on the mechanical response of SMA-CFRP composites through numerical modeling and experimental validation, including microscale mechanical property calculations, macroscopic tensile analysis, and mesoscale RVE-based simulations. The results reveal that the pronounced mismatch in thermal expansion coefficients between SMA wires and the CFRP matrix is the primary cause of significant residual stress concentration during curing. The peak compressive residual stress within SMA-CFRP reaches 174.5 MPa, considerably higher than that in pure CFRP. Furthermore, the RVE model captures stress gradients and directional anisotropy at the interface, arising from elastic modulus mismatches between adjacent phases. These residual stresses lead to reductions in both strength and stiffness, by approximately 4–5 % and 5–8 %, respectively. The findings demonstrate that SMA-reinforced composites require careful interfacial design and process optimization to fully realize their mechanical advantages.