Micromechanical analysis of layered systems of MMCs subjected to bending––effects of thermal residual stresses

A three-dimensional finite element micromechanical model is presented to study the effects of manufacturing process thermal residual stresses on the mechanical behavior of layered systems of metal matrix composites subjected to four point bending. The presented model contains layered systems, consisting of layers of monolithic titanium alloy (IMI834) and unidirectional fiber reinforced titanium metal matrix composite (SiC/Ti). A representative volume element (RVE) was defined and appropriate boundary conditions were imposed to apply bending and temperature change simultaneously on the model. In an agreement with experimental data, the model is able to predict asymmetric behavior of the composite in tension and compression on the bottom and top surfaces of the beam. This is due to the existence of a high level of thermal residual stresses arising from cool-down from manufacturing temperature. As a result of this asymmetric behavior, the neutral axis of the beam during bending moves from the mid-surface through the compressive part of the beam.