First ply failure analysis of laminated composite thin hypar shells using nonlinear finite element approach

In this paper the nonlinear finite element approach is used to solve the problems of first ply failure of laminated composite skewed hypar thin shell roofs. The geometrically nonlinear strains terms are incorporated in the present finite element code which is validated through solution of the problems solved and published by earlier researchers. The first ply failure loads of the industrially popular, aesthetically appealing hypar shells are studied meticulously for varying aspect ratios and thicknesses for clamped boundary condition. The paper gives specific recommendations regarding choice of linear and nonlinear approaches for obtaining failure loads in different specific cases.