Crack Path Simulation by the MVCCI Method: Different Approaches and Applications

摘要

The modified virtual crack closure integral (MVCCI) method has been proved to be a highly effective numerical procedure for the analysis of various crack problems in linear elasticity. In the present paper it will be shown that the MVCCI method in conjunction with multiple mesh analysis can also readily be utilised for the numerical prediction of curved fatigue crack growth under proportional loading conditions. Further, it will be shown that the common computer-aided two-dimensional crack path prediction can be considerably improved in accuracy by using a predictor-corrector procedure. In combination with the MVCCI method, this results in a step-by-step parabolic approximation of the simulated crack path. By this method, both the new locus of the crack tip and the slope of the crack path at this point can be computed simultaneously by the SIFs for only one virtual tangential crack extension with respect to the previous step. In order to evaluate the validity and efficiency of the proposed higher order crack path simulation method in relation to the well-established basic strategies, experiments of curved fatigue crack growth are carried out with specially designed specimens under proportional lateral force bending. In all the cases considered, the computationally predicted crack trajectories show an excellent agreement with the different types of curved cracks that are obtained in the experiments as a function of the position of crack initiation.