Geometrically nonlinear composite beam structures: optimal design

This paper applies the formulation and the finite element analysis and sensitivity analysis model developed in a companion paper to the optimal design of various geometrically nonlinear composite laminate beam structures. The element design sensitivities are imbedded in the finite element code and the global sensitivities are interfacing the analysis with a nonlinear programming optimizer. Laminate thickness and lamina orientations are considered as design variables. Mass, stiffness and deflection are used as objectives or combined as multiobjective functions. The nonlinear critical load or the Tsai-Hill stress failure index, are used as constraints. Postcritical domain behavior allows the advantageous substitution of the critical load constraint by a displacement constraint.