Compressive Strength of Composite Lattice Structures

Abstract

This research investigates the strength of composite lattice cylindrical and conical shells under axial compressive loads. The lattice structures are composed of circumferential and helical members, whose cross-sections are rectangular. The failure modes of both cylindrical and conical composite lattice shells are examined. New design constraints to achieve weight efficient structures with high failure loads is presented. Two main failure modes, general buckling as a shell and excessive shear stress in the members, are considered. The main emphasis is placed on the effects of geometrical configuration of the structure and the manufacturing process. Filament winding was used as the method of construction to automate the fabrication process and to minimize manufacturing costs. Numerical results are obtained by finite element analysis which are compared with experimental solutions. The motivation of the present work was to find the optimal winding pattern to which filament winding can be easily applied and still provide the highest strength to weight ratio. The final result of this research includes the numerical and experimental analysis of composite lattice cylindrical and conical shells via filament-winding. This work provides an understanding of composite lattice structures that will be useful in preliminary design of such structures.