The dependence of damping capacity of PMMCs on strain amplitude

For the particulate-reinforced metal-matrix composites (PMMCs), when the in terface is considered as ideal, the damping mechanisms mainly come from two aspects. One is the intrinsic damping of component phase and the other is the energy dissipation caused by local micro-plastic deformation during ext ernal loading. According to this principle, the dependence of the damping c apacity of SiCp/Al composite, at room temperature. on strain amplitude, has been simulated by employing cell method in this paper. The results show th at the damping capacity of SiCp/Al composite is independent of the strain a mplitude epsilon(0) when epsilon(0) is comparatively low. But, when the str ain amplitude epsilon(0) reaches a critical value epsilon(crit), the dampin g capacity increases rapidly with the strain amplitude epsilon(0). The resu lts also show good coincidence to the model of G-L dislocation damping theo ry. It can be concluded that the dependence of the damping capacity on the strain amplitude epsilon(0) is due to the energy dissipation caused by loca l micro-plastic deformation near the interface of Al/SiC for the difference of the elastic modulus. (C) 2000 Elsevier Science B.V. All rights reserved .