Micromechanical Model for Slit Damaged Braided Fabric Air-Beams

摘要

A micromechanical model has been developed that will allow the study of a slit-damaged braided fabric air-beam structure. As such, the relevant system of non- dimensional ordinary differential equations are derived and solutions are given for the stress concentration near the broken yarns. This knowledge will contribute to the prediction of damage growth and the ability to compare different fabric materials for their damage tolerance. A simplification of the analysis has been shown to be possible when a parameter, e, the ratio of yarn tensions due to inflation to the yarn stiffness is small, approaching zero. In such a case, the equations for the braided fabric can be reduced to those of the plain weave fabric, so that the stress concentrations are the same as those for woven fabrics. As it turns out, an important result of the present analysis is that the stress concentration factor is, in fact, independent of the parameter, e, and the helix angle of the braided fabrics. This means that much of what has been learned in the study of damage in woven fabrics can be used for braided fabrics.