Design optimization of laminated fiber composites

Laminated Fiber Composites are finding a wide range of applications in structural design especially for light weight structures that have stringent stiffness and strength requirements Finding an efficient composite structural design that meets the requirements of a certain application can be achieved not only by sizing the cross-sectional areas and member thicknesses but also by global or local tailoring of the material properties through selective use of orientation, number and stacking sequence of the laminae that make up the composite laminate.The work presented here treats the design optimization problem involving minimum weight design of fiber composite laminates subject to inplane loading conditions which takes into account membrane stiffness and strength constraints The problem is a non linear mathematical programming problem in which the thicknesses of the material placed at preassigned orientation angles are treated as the only design variables. Computational efficiency is achieved by using constraint deletion techniques in conjunction with Taylor series approximation for the constraints retained the optimization algorithm used employs a sequence of lineal programs to converge to the optimum solution.The method presented offers an efficient and practical optimum design procedure.