Numerical Modelling of Crack Growth in Material Models of Fibrous Composites

Abstract

Experimental investigations of fracture phenomena in thermomechanically loaded fibrous composites demonstrate the appearance of different failure mechanisms, like matrix and interface cracks as well as of fiber breakings. In addition, the existence of branched crack systems consisting of a combination of those elementary failure mechanisms has also been observed several times. Therefore, in this paper the numerical modelling of complicated crack systems has been performed, consisting of a combination of matrix and fiber cracks where the latter are originated by local asymmetrical interface cracks and according to experimental results arise in a single layer of a thermomechanically loaded fibrous composite structure. The mathematical modelling of such branched crack systems in thermomechanically loaded two-phase compounds leads to mixed boundary value problems of the thermoelasticity. The corresponding solutions were obtained by using a closed finite element program capable of an automatic mesh generation. Further, special emphasis has been given to the crack path prediction of thermal cracks initiated in a plastic matrix/glass fiber reinforced composite structure by using a newly established crack growth criterion based on the total energy release rate of a quasistatic mixed-mode crack extension. This numerical simulation of the crack growth process in appropriate material models should allow a better understanding of the fracture behaviour of fibrous composites on a micromechanical level.KeywordsStress Intensity FactorEnergy Release RateInterface CrackCrack ExtensionStrain Energy Release RateThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.