Multiobjective optimization of fiber composite shells for maximum buckling load and imperfection tolerance.

Abstract

The performance of thin-walled structures, which are endangered by buckling, is often strongly influenced by geometrical imperfections. It is impossible to know in advance the imperfections,which will be present in the real structure. Nevertheless, their influence has to be taken into account already at the design process. Attempts to indentify characteristic imperfections due to specific manufacturing processes overcome this difficulty only partly, as they do not consider imperfections coming into existence after fabrication. The remedy is, to build imperfection tolerant structures. For that purpose, a simple means to measure imperfection tolerance is defined and a multiobjective optimization formulation is proposed to design fiber composite shell structures, which simultaneously exhibit high imperfection tolerance and high buckling load. By example of axially compressed CFRP cylindrical shells first computational and experimental results are given to demonstrate the feasibility of the concept, and to identify needs for further research.