THE EFFECT OF FIBER DAMAGE ON THE LONGITUDINAL CREEP OF A CFMMC

Fiber failures which may exist in a continuous fiber composite before the composite is loaded or generated while the composite is loaded, in troduce an additional strain component not included in existing contin uous fiber models. Equations are developed which can be used to calcul ate the magnitude of this additional strain. A Finite Element Model (F EM), in the form of a Representative Volume Element (RVE), calculates the stress field surrounding a fiber break. Statistical analysis is us ed to infer the behavior of a large composite sample from the stress a nalysis of a single break. The creep strain, the time to failure, and time-dependent composite strength can all be calculated by combining t he FEM results, the statistical analysis model, and knowledge of the i nitial average fiber length. Important variables included in the calcu lation are process-related parameters such as the fiber-matrix interfa ce strength and roughness.