Optimization of composite I-sections using fiber angles as design variables

A problem formulation and solution methodology for design optimization of l aminated composite I-sections is presented. Objective functions and constra ints are given in the form of beam stiffnesses. Two different objective fun ctions are considered, maximum beam bending stiffness and maximum beam axia l stiffness. Fiber directions in the beam walls are treated as design varia bles. It is assumed that the beam is constructed using unidirectional tape, and manufacturing issues associated with the use of unidirectional tape ar e discussed and included as constraints in the problem formulation and solu tion. The paper demonstrates that the design optimization of composite thin -walled beams is a complex global optimization problem that cannot be solve d by means of traditional convex programming. Therefore, the solutions desc ribed are found using a global search algorithm., Improving Hit-and-Run, wh ich allows the design variables to be either continuous or discrete with a user-specified discretization interval. Numerical results for two material systems and nine different design families for manufacturing composite I-se ctions are presented. (C) 2001 Elsevier Science Ltd. All rights reserved.