Stress concentration at a hooked-fiber textile composite layer with local technological defects under biaxial tension on transversal origin

A new model has been developed to simulate a woven textile composite layer with a polycrystalline matrix. Based on the numerical solution of the boundary-value problem by the finite-element method, the values of stress concentration caused by local processing defects (break in a fiber, closed internal pore) under symmetric biaxial macrodeformation are obtained. The numerical solution by the finite-element method is received using the part of SALOME-MECA framework, the non-commercial package Code-Aster. The regions of maximum stress disturbance coefficients in the textile composite layer are determined. The cause of marked increase of stress disturbance coefficients is the contact with friction between the fibers of reinforcing skeleton and the shifts are the main mechanisms of polycrystalline matrix damaging. It is shown that application of additional processing operations to fill the formed voids by matrix material can decrease stress concentration and increase the ability of a material to withstand external force loads. The mechanisms responsible for initiation of damages in a polycrystalline matrix are determined.