Response and failure of square laminates under combined loads

A non-linear finite-element method (FEM) which is based on the von Karmanʹs assumptions, the Mindlinʹs plate theory and the principle of minimum total potential energy is used to study the first-play failure of thin laminated composite plates under combined loading i.e. transverse load with uni-axial compression and transverse load with in-plane shear. The mode of failure, the first failed layer number, the first failed node number and the associated maximum transverse deflection are found at different values of load combinations. Failure envelopes in the form of interaction curves are obtained for five types of laminate using the Tsai–Hill failure criterion and for (±45/0/90)2s laminate using the other failure criteria as well.