Three-Dimensional Fracture Analysis and Experimental Investigation of Model Unidirectional Discontinuous Tow Composite Laminates

Abstract

The purpose of this work is to perform analytical modeling and experimentally produce idealized composites reinforced with discontinuous fiber tows to evaluate the theoretical upper limits of tensile strength as compared to continuous fiber composites. The idealized composite represents a staggered mosaic of prepreg tape strips of equal width and length. Three-dimensional analysis was performed to evaluate the energy release rate of the possible damage accumulation modes, such as vertical splits and delaminations emanating from tape strip ends. Realistic estimates of the failure strain of the discontinued tow composites was obtained by comparing the calculated energy release rates to the critical Mode II energy release for axial cracking in the material system. The predicted failure strain as a function of the strip geometry was also in good correlation with the experimental results.