TÍTULO: Structural Optimization of Laminated Composite Shells and Aeroelastic Tailoring Applications
PALESTRANTE: Dr. Carlos Eduardo de Souza (UFRGS)
DATA: 17/10/2014 (sexta-feira)
LOCAL: Centro de Tecnologia, Bloco G, sala 205.
RESUMO: Composite structures are in constant development, specially for use in aeronautical structures. New manufacturing technologies, like fiber placement techniques, justify the studies on new design methodologies of laminated composites. Two problem types are considered: displacements under multiple static loads and aeroelastic stability. The static loads case considers the combination of loads associated to different operational conditions. The aeroelastic stability case is related to the flutter onset speed of laminated plates and shells. A few approaches for solving problems of topology and orientation optimization of laminated shell structures are then proposed. In a first moment, a two-level strategy is used, optimizing sequentially the orientation of chosen plies on all elements and then optimizing plies topology. The design variables are the relative densities and the principal material direction orientation of each layer in an element, aiming volume minimization under mean compliance constraints. The strategies proposed for single and multiple load cases are adapted for solving the problem of maximizing the flutter speed. In this case, structural modal analyses are necessary for solution of the aeroelastic stability in the generalized domain. The Sequential Linear Programming method is used to solve the optimization problems. An eight node degenerated shell finite element with explicit integration on the thickness direction is used to assembly the stiffness and mass matrices for laminated composites. The optimization analyses are implemented inside a framework in Matlab. Some illustrative examples are presented to demonstrate the applicability of the proposed optimization approaches. Issues still found and ongoing developments are discussed.