粒子強化型複合材の均質化法による変形挙動のモデル化とシミュレーション

抄録

In order to clarify the characteristic feature in the deformation behavior of particulate-reinforced composite materials, a homogenization method has been developed for the materials obeying the strain and strain-rate dependent constitutive equation that takes into account for the characteristic length scale by using the strain gradient theory and developed the corresponding finite element method. By means of the computational simulation under the plane-strain condition, a series of simulations with inhomogeneous deformation behavior of composite materials containing different volume fractions, size and distribution pattern of reinforcement subjected to different loading direction have been performed. As a result, it has been clarified that the resistance of composite material to deformation is substantially increased with the refinement of the particle size and significantly dependent on the loading direction under constant volume fraction of the reinforcement. This result indicates that the present simulation method has the capability of predicting the experimentally observed particle-size-dependent macroscopic characteristic feature of the composites. The main mechanism of the increase of the deformation resistance in the plastic range is attributable to the high strain gradient appearing in the matrix material, which increases with decreasing the distance between the particles. Therefore, the regularization of the distribution pattern that increases the value of the maximum strain gradient in the matrix contributes toward improving the resistance to macroscopic deformation behavior.