Prediction of delamination front's advancement direction in the CFRP laminates with mechanical couplings subjected to different fracture toughness tests

The paper deals with formulation of an analytical tool for predicting the direction of interlaminar crack propagation in the CFRP composites with mechanical couplings. It is a consecutive work in the study and covers analysis of the typical fracture toughness tests (DCB, ENF and ELS) applied to fiber-reinforced composites with general ply configurations. The results of the VCCT calculations of delamination onset and propagation performed in the Abaqus environment were next subjected to analysis with Python scripts and the formulated mathematical apparatus. This revealed the usefulness of the proposed equipollent vector and the associated variables in prognosis of the front shape asymmetries and the overall propagation direction. The considerations have been performed in 2D, but the formulae are thought to be ready for the prospective 3D analyses. The compatibility with the results obtained in the preceding articles was underlined.