Fe-simulation of crack paths in the real microstructure of an Al(6061)/SiC composite

Ductile failure in Al(6061)/SiC has been simulated by means of advanced finite element methods. In contrast to continuum damage mechanics, the emphasis is on the influence of the local microstructure (phase arrangement), and on the course of the crack through the phase landscape. Multiphase elements and an automatic element elimination technique allow one to calculate the stress and strain microfields and to simulate the stages of ductile fracture, i.e. void formation, growth and coalescence, up to failure. For several stress-strain criteria the crack path has been calculated and compared to the observed path. Using the Rice and Tracey damage parameter, which takes the complete loading history into consideration, the observed crack path could be exactly reproduced. A number of simpler criteria were tested, but were clearly inferior to the Rice-Tracey parameter.