COMPUTATION OF FRACTURE-MECHANICAL PARAME TERS FOR SPECIMENS WITH ELASTIC ANISOTROPIC PROPERTIES BY FINITE-ELEMENT TECHNIQUE

A method for direct calculation of the different mode m stress intensi ty factors K-m from the crack tip stress- or deformation fields of a f inite element model is proposed that is suitable especially for linear elastic, anisotropic materials. The practical aim of the investigatio n was to get a procedure to split experimental results for mixed mode energy release rate, G(sum), into the parts G(m) of the pure modes m. This problem will raise for instance in the experimental characterizat ion of delamination behaviour of fibre-reinforced polymer composites w ith complicated sample geometries. The method is tested and the accura cy of the results is compared with well established solutions for the ,,double-cantilever-beam'' (DCB-) specimen.