Effect of cutout geometry on the failure strength of symmetric laminates under uniform heat flux

Abstract

The present work aims to investigate the thermal stress distribution in an infinite symmetrical laminated composite plate with a polygonal cutout to determine the laminate failure strength based on the first ply failure according to Hashin–Rotem and Tsai–Wu criteria. Lekhnitskii’s solution technique has been used to obtain the required potential functions. The extension of the technique used for the circular and elliptical cutouts into polygonal cutouts was performed using conformal mapping function in accordance with the procedure of complex variables. The main parameters such as cutout orientation, bluntness factor, the aspect ratio of the cutout, as well as stacking sequences in composite plates with symmetrical laminates made of glass/epoxy material containing triangular, square, pentagonal, and hexagonal cutouts have been examined. According to the research findings, it is possible to improve the failure strength of perforated plates by appropriate selection of cutout shapes along with the optimum values of the effective parameters. The unexpected result was that circular geometry was not always the best choice for the cutout because the selection of appropriate values for the parameters under consideration for a laminate with non-circular cutout leads to higher failure strength compared to the same plate with circular cutout.