بررسي اثرات تورق بر بار بحراني صفحات مواد مركب لايه يي تخت بار برشي داخل صفحه

EFFECT OF DELAMINATIONS ON THE BUCKLING OF COMPOSITE LAMINATES UNDER IN-PLANE SHEAR LOAD

The presence of delaminations reduces the buckling load of composite laminates considerably. This paper examines this effect when the laminate is under in-plan shear load. A rectangular composite laminate with a single or multiple embedded delaminations is considered and a buckling analysis is performed using Mindlin plate elements in a finite element method. The buckling load and mode are obtained by solving an eigenproblem. Unconstrained buckling analysis may result in physically inadmissible modes. To prevent the overlap between the sublaminates and obtain the admissible result, a suitable method is introduced to enforce the required constraints in a penalty function method. Numerical results show the effects of the number, size and depth of delaminations and boundary conditions of the laminate on the buckling load.