Design Optimization of Laminated Composite Plates with Static and Dynamic Considerations in Hygrothermal Environments

摘要

Motivated by needs such as those in the aerospace industry, this paper develops and demonstrates a method for optimizing laminated composite shell components considering the natural frequency, damping and deflection subjected to a concentrated load on the center of the plate in hygrothermal environments by manipulating individual ply angles and thicknesses. Optimization is performed by synergizing an FEA with a gradient-based modified feasible direction optimization algorithm. The objective is to minimize the weight of the plates within the given design space via the constraint of the first natural frequency, dampings of the first vibration modes and deflections caused by the applied hygro-thermo-mechanical loads. Illustrative applications involve six-ply symmetric rectangular laminated panels simply supported along four edges, although the method is applicable to more complicated laminates, geometries and boundary conditions. The panel geometry is discretized into specially-developed, 3D-degenerated eight-node shell isoparametric layered composite elements. Through a numerical example, it is shown that hygro-thermal effects play an important role in the optimal design of laminated composites.