Fiber Reinforcement of Metal Matrices Against Plastic Flow

The uniaxial stress-strain behavior and plastic flow in rate-independent plastic flow for transverse loading of continuous fiber-reinforced metal-matrix composites are examined in this paper. Cell models with different packing arrangements are employed to analyze the effects of fiber cross-sectional shapes (square, circular, and diamond) and periodic distributions (square, hexagonal and diagonal packing arrays) as well as transverse loading directions (45°, 0°, or 90°) on the transverse plastic deformation of metal-matrix composites reinforced with periodically distributed, aligned continuous fibers. Calculations were carried out using increasingly refined meshes to demonstrate numerical convergence. The calculations of the alternations in matrix field quantities in response to controlled changes in the fiber packing array give insights into the effects of fiber clustering on the transverse plastic flow. The results indicated that the overall transverse plastic flow of the composites is sensitive to fiber geometric parameters, such as fiber shape, packing arrangement and volume fraction, and to the transverse loading direction. The stress contours demonstrated that the interference of fibers with flow paths plays an important role in the transverse strengthening mechanism.