Application of a cycle jump technique for acceleration of fatigue crack growth simulation

A method for accelerated simulation of fatigue crack growth in a bimaterial interface is proposed. To simulate fatigue crack growth in a bimaterial interface a routine is developed in the commercial finite element code ANSYS and a method to accelerate the simulation is implemented. The proposed method is based on conducting finite element analysis for a set of cycles to establish a trend line, extrapolating the trend line spanning many cycles, and use the extrapolated state as initial state for additional FE simulations. The inputs of the developed method are the crack growth rate vs. energy release rate diagrams for different mode-mixities. Once these diagrams for a specific interface are available, fatigue crack growth in any structure with the same interface can be simulated. Using the developed method, fatigue crack growth in the interface of a sandwich beam is simulated. Results of the simulation show that with fair accuracy, using the cycle jump method, more than 70% reduction in computation time can be achieved.