Statistical Long-Term Creep Failure Time of Unidirectional CFRP

Abstract

The tensile strength along the longitudinal direction of unidirectional CFRP constitutes important data for the reliable design of CFRP structures. This study establishes a method of predicting statistical creep failure time under tension loading along the longitudinal direction of unidirectional CFRP based on the matrix resin viscoelasticity. First, the accelerated testing methodology (ATM) to predict the long-term creep failure time of CFRP laminates statistically from the statistical static strength of CFRP and the creep compliance of matrix resin measured at various temperatures was proposed based on Christensen’s theory for viscoelastic crack kinetics. A formulation for the prediction was established. Second, the statistical long-term creep failure times obtained under tension loading along the longitudinal direction of unidirectional CFRP were predicted based on our proposed methodology using our developed testing system for resin-impregnated CFRP strands as specimens. Third, results clarified that two fracture modes existing in CFRP strands under static and creep loading and viscoelastic parameter n_R showing sensitivity to the matrix resin viscoelasticity change drastically with the fracture mode.