Postbuckling optimization of a reinforced composite panel using discrete firefly algorithm
Pedro Henrique Herrera1; Marco Antônio Luersen1; Rubem Matimoto Koide2
1 Universidade Tecnológica Federal do Paraná - UTFPR - Câmpus Curitiba; 2 FAE Centro Universitário; Universidade Tecnológica Federal do Paraná - UTFPR - Câmpus Curitiba
doi:10.20906/CPS/CILAMCE2017-0386
Resumo
Laminated composite materials have high strength-to-weight and stiffness-to-weight ratios. These characteristics are important in areas such as automotive and aeronautics, where reducing mass of components is essential. This also implies on manufacturing thin-walled parts, which are usually subjected to structural instability. In addition, optimization techniques can be applied to improve the structural design. Thus, this work aims to optimize a composite panel in the postbuckling regime, using the firefly algorithm. The problem studied here consists of a flat panel of laminated composite material, with six reinforcements (stiffeners) subjected to in-plane shearing load. The objective of the optimization is to find the best positions of the stiffeners and the best stacking sequence that maximize the postbuckling load without failure according to the Tsai-Wu criterion. Two cases of optimization are investigated. The first one considers only the positions of the stiffeners as design variables, and the second one both, positions and orientations of the plies, are the design variables. The structural response of the panel is obtained through finite elements in a model built in ABAQUS code. Shell-like elements are used and the postbuckling analysis is divided into two steps. Initially, a linear buckling analysis is performed to obtain the first three buckling modes, which are used to introduce imperfections in the model. Then, a large displacement nonlinear analysis is carried on to obtain the maximum load before failure. The optimization algorithm is based on the behavior of fireflies. They emit flashes of light to attract partners and move toward to the brighter ones. The attractiveness is related to the intensity of the emitted light and is proportional to the distance between them. In the algorithm, the luminosity intensity is determined by the value of the objective function. Both the position of the stiffeners and the ply orientations assume discrete values, thus, the firefly algorithm was adapted to this situat
Palavras-chave: Optimization; Laminated composite materials; Postbuckling