Effect of CFRP plates on the crack growth of a steel plate with notches in different directions

When using a CFRP plate to suppress fatigue cracking, it is highly effective to orient the CFRP fibers in a di-rection perpendicular to the crack growth direction. In this research, we have studied the use of an unidirectional CFRP plate to suppress crack growth in a steel plate that has a fatigue crack by bonding the CFRP plate to the steel plate, with the crack either perpendicular or diagonal to the orientation of the CFRP plate. Finite element method was used to determine the mixed mode stress intensity factor, and the fatigue test result was compared with the crack growth analysis, to make a qualitative evaluation of the analysis method.