FEM elasto-plastic analysis of a new manufacturing method for covering the free surface of unidirectional composites

摘要

Fiber/matrix debonding at the free surface of unidirectional composites deteriorates their performance and ultimately reduces the working life of these materials. Identifying the source, controlling the propagation and elimination of the damages has been the subject of many research attempts. The results show that the singular radial thermal residual stress at the fiber/matrix interface on the free surface of composites is the main reason for initiation of the debonding. Also, it has been experimentally and numerically proven that a thin layer of matrix-like cover on the free surface could highly help in elimination and/or reduction of the damage. However, the results were limited to the samples, which their free surface is covered during their production process. To extend the results to the pre-made composites, one should be able to deal with the existing free surface debondings and/or the residual thermal stresses. Here, in this study, a new manufacturing method for covering the free surface of metal matrix composites is suggested and it is numerically shown that elimination of the end effects before casting the covering materials on the free surface is necessary. Different manufacturing schemes are considered and numerically tested. (c) 2005 Elsevier B.V. All rights reserved.