Design Guidelines in Nonconventional Composite Laminate Optimization

Abstract

A method for optimising ply drop locations in composite laminates is developed using ideas from topology optimisation. The design is parametrised using a fibre angle and fictitious density distribution for each ply. The solution proceeds using a successive conservative convex approximations strategy. The structural responses are approximated separately in terms of the angle and fictitious density distributions of each ply. Explicit penalisation of intermediate densities is used to force the densities to either one, ply coverage, or zero, no coverage. Ply drop locations are identified as the boundary between regions having densities near one and those near zero. The ply drop optimisation is combined with fibre angle optimisation by alternating the optimisation between the corresponding set of variables. Optimised variable stiffness, variable thickness composite laminates are obtained. Initial results show that large improvements in buckling load of flat plates can be obtained by combining ply drop and fibre angle optimisation.

Buckling and free vibration study of variable and constant-stiffness cylindrical shells

“…They demonstrated that substantial structural improvements in strength, stiffness and buckling load could be reached by applying curved fibers. Other researchers have also contributed to the knowledge of flat tow-steered laminate plates [7][8][9][10][11]. Recent progress in variable-stiffness design and optimization of fiber-reinforced composite structures was summarized by Ghiasi et.…”

A Buckling Analysis and Optimization Method for a Variable Stiffness Cylindrical Pressure Shell of AUV

“…This causes variable fiber angle and properties including the lamination stiffness compared with that of the CS composite structure. Thus, the variable fiber angle composite structure is usually called as the variable stiffness (VS) composite structure [9][10][11][12]. Figure 1 shows the layups for two different composite laminates.…”