Multilevel optimization of composite panels under complex load and boundary conditions

Due to their complexity and large numbers of design variables, aerospace structures, such as aircraft wings, are best optimized using a multi-level process. In addition to simplifying the optimization procedure, such an approach allows a combination of different methods to be used, increasing the efficiency of the analysis. This paper presents a technique based on the usage of exact finite strip software, VICONOPT, with the finite element analysis package, ABAQUS. The computer programme VICONOPT is computationally efficient but provides solutions for a restricted range of geometries and loading conditions. Finite element analysis allows accurate models of structures with complex geometries to be created but is computationally expensive. By combining the two, these limitations are minimised, whilst the strengths of each are exploited. The fundamental principles of this multi-level procedure are demonstrated by optimizing a series of curved composite panels under combined shear and in-plane bending subject to buckling constraints.