A general and effective approach for the optimal design of fiber reinforced composite structures

This paper presents a general and effective procedure based on a mathematical programming approach for composite structures optimal design, under weight, stiffness and strength criteria. Effective means that the developed approach is able to find a local optimum in few iterations, even with a large number of design variables. In addition, as the formulation may include strength constraints, it is shown that not only plies thickness but also fiber orientations should be considered as design variables. Besides this, it is explained how these angular variables can improve the structural performance. The generality of the approach is related to the fact that the developed optimization technique is not only dedicated to the design of particular laminates configurations, but is also reliable for general problems including isotropic and/or anisotropic materials, as well as other structural responses. The design problem formulation relies on a direct parameterization of the laminates in terms of the physical design variables, that is orientations and thicknesses, and not on alternative ones like the lamination parameters. Numerical applications, including a non-homogeneous composite membrane design problem and an industrial test case, are presented.