The dependence of damping capacity of PMMCs on strain amplitude

For the particulate-reinforced metal-matrix composites (PMMCs), when the interface 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 external loading. According to this principle, the dependence of the damping capacity of SiC_P/Al composite, at room temperature, on strain amplitude, has been simulated by employing cell method in this paper. The results show that the damping capacity of SiC_P/Al composite is independent of the strain amplitude ε₀ when ε₀ is comparatively low. But, when the strain amplitude ε₀ reaches a critical value ε_crit, the damping capacity increases rapidly with the strain amplitude ε₀. The results also show good coincidence to the model of G-L dislocation damping theory. It can be concluded that the dependence of the damping capacity on the strain amplitude ε₀ is due to the energy dissipation caused by local micro-plastic deformation near the interface of Al/SiC for the difference of the elastic modulus.