Variable Singularity Power Wedge Element for Multilayered Composites

Multilayered composites can be weakened by local failures, which can give rise to singular stress fields. Singularities can be removed or integrated to obtain bounded quantities which may be used for the analysis. In any case, the participation of singular stresses should be identified. Serving this purpose, a new mixed singular wedge element based on interpolation functions with a variable singularity power is developed, which can adapt to the problem and can represent the non-singular fields as a particular case. The displacements and the interlaminar stresses are assumed as nodal d.o.f. to a priori fulfill the kinematic and stress contact conditions at the material interfaces and the stress boundary conditions in point form. The application to sample cases taken from literature shows that the element can be successfully employed for the analysis of singular fields. The variable singular representation and the mixed formulation give more accurate results than their displacement-based, non-singular, or singular counterparts with a fixed singularity. The failure loads of initially delaminated specimens are accurately predicted either using the virtual crack closure technique or a mesoscale model by running in a reasonable time on a personal laptop computer.