Optimum laminate design for strength and stiffness

A method is presented for minimum weight optimum design of symmetric fibre‐composite laminates subject to multiple in‐plane loading conditions which takes into account membrane stiffness requirements and strength limitations. The problem is cast as a non‐linear mathematical programming problem in which the thicknesses of material placed at preassigned orientation angles are treated as the only design variables. The non‐linear programming formulation is transformed into a sequence of linear programs employing an adaptation of the method of inscribed hyperspheres in which only critical and near critical constraints are considered at each stage in the procedure. Example applications illustrate that the method presented offers an efficient and practical optimum design procedure for the fundamental and recurring problem treated.