Increased breaking strain of carbon fiber-reinforced plastic and steel hybrid laminate composites

Synergistic effects of carbon fiber-reinforced plastic (CFRP) and steel hybrid laminate composites were investigated systematically by static and dynamic tensile testing. Various hybrid laminate composites were prepared by varying the adhesion between the CFRP and steel, the layup sequence, and the volume fraction of the CRFP. The fracture strain of the CFRP within the hybrid laminate composites increased, e.g., from 1.94% for pure CFRPs to 2.21% for the steel/CFRP/steel case. Finite element analysis and fractography established that transverse compressive stress was the main source of the improvement. Different Poisson's ratios led to transverse compressive stress on the CFRP layer after yielding of the steel during the tensile test. This stress delayed the fiber-splitting behavior of the CFRP, leading to further deformation and thus increasing the breaking strain and tensile strength of the CFRP within the hybrid laminate composites. Our results provide insight into the design of ductile composites using CFRP and steel through optimization of the laminate structure.