Numerical modelling of particle distribution effects on fatigue in Al-SiCpcomposites

Various reports in the literature have highlighted the effects of particle distribution on the fatigue behaviour of particulate reinforced metal matri x composites (PMMCs), although few attempts have been made at modelling suc h effects. A micromechanical understanding of the effects of clustering on short crack growth behaviour in Al-SiCp composites has been achieved via fi nite element modelling. Comparison of preliminary models with the literatur e has shown that shielding/anti-shielding effects were significantly affect ed by the relative sizes of the particle and the overall model such that, w hen edge effects were removed, a crack was predicted to be accelerated rath er than decelerated as it propagated through closely spaced pairs of partic les. Consistent differences were identified between models with homogeneous versus clustered particle arrangements in terms of crack path morphologies and local crack-tip stress intensity fluctuations. Furthermore, predicted influences of clustering on growth rates in the numerical models were found to be consistent with previous experimental results (i.e. growth rates ros e with increased clustering), demonstrating that load transfer effects asso ciated with changes in particle distribution may play a direct role in cont rolling the growth of short cracks in these materials. Crown Copyright (C) 2001 Published by Elsevier Science B.V. All rights reserved.