Strain invariant failure theory invariant properties of domestic carbon fiber/resin composites

Strain invariant failure theory (SIFT) is a novel micromechanics-based failure criteria for composites, which could be applied to all composite failure analysis. The micromechanics model was built to obtain the mechanical and residual thermal strain aplification factors of fiber and resin. Tensile properties of the domestic composites CCF300/5228、CCF300/5428 and T700/5428 in various unidirectional laminate configurations were measured. Test results were used to obtain SIFT invariant properties. The effect of the component of composites on the SIFT invariant properties was investigated. The results show that the critical first strain invariant and von-mises strain of matrix are dependent on resins, while critical von-mises strain of fiber depends on fibers. SIFT can be used for the failure analysis of domestic composites.