Accelerated fatigue crack growth simulation in a bimaterial interface

A method for accelerated simulation of fatigue crack growth in a bimaterial interface (e.g. in a face/core sandwich interface) is proposed. To simulate fatigue crack growth, a routine is incorporated in the commercial finite element program ANSYS and a method to accelerate the simulation is implemented. The proposed method (the cycle jump technique) 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 finite element simulations. A control criterion is utilized to ensure the accuracy of the cycle jumps. The inputs of the developed scheme are the crack growth rate as a function of energy release rate for discrete mode-mixities. If these relationships are available for a specific interface, interface fatigue crack growth in any structure with the same interface can be simulated. Using this approach, fatigue crack growth in the face/core interface of a sandwich beam is simulated. Results of the simulation show that with fair accuracy, using the cycle jump technique, more than 65% reduction in computation time can be achieved. Results show that in highly nonlinear problems the control parameter needs to be chosen with care. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.