Quick optimum design of axially compressed, thin/walled FRP cylindrical shells.

Abstract

Optimization of axially compressed, thin-walled FRP (fiber reinforced plastic) cylindrical shells is considered in detail. The problem is defined as sequence of buckling load maximizations with fiber orientations taken as design variables, and it is solved by application of mathematical programming and by lattice search. The buckling load is computed as 'classical' buckling load. The suitability of this model for optimization purpose is checked by buckling tests and by computations based on more sophisticated struktural models. From systematic evaluation of the multitude of numerical data, simple design rules are identified, which enable the design engineer to find out very quickly, without optimization runs, virtually optimum fiber orientations. He simply has to enter a table and to compute the buckling load.With a view to a quick buckling load assessment, classical buckling load computed for a partcular shell configuration and a specific CFRP material are given, and use of a simple formula enables the designer to extrapolate the load from this shell configuration to that in consideration. Some additional findings are presented, which might be of use to gain experiencewith regard to the properties of optimal fiber composite structures.