EFFECTS OF BAND WEAVING ON FIBER STRENGTH IN FILAMENT-WOUND COMPOSITESTRUCTURES

Filament winding of composite structures generally causes fiber bands to weave or undulate throughout the structure in a non-periodic fashio n, except for hoop-only winding. This causes the filament-wound fiber bands, made from multiple groups of filaments, called tows, to fail be low the fiber strength of straight fibers. This fiber failure strength reduction is investigated by performing a finite element stress analy sis and developing a strength-of-material type closed-form solution fo r curved fibers. The stress analysis results from both methods are com pared to actual test results conducted on single and double type weave patterns. The predicted failure stress from the analysis closely matc hes the experimental results. Application of this work to filament-wou nd composite pressure vessels is discussed.