パーコレーション理論を用いた多孔質ポリウレタン/アルミナ粒子複合材料の機械的性質に及ぼす気孔分布の影響評価

抄録

This research aims at revealing relationships between pores size distribution in porous components with its mechanical properties applying critical porosity by percolation theory. The surgery of artificial hip joints has been persistently increasing due to super-aging society. However, the service lives of the artificial hip joints are unexpectedly limited by loosening, and the extents of loosening highly depends on mechanical property of embedded natural bones. This proposed optimization method is to seek for higher strength of porous components with maintaining its light weight. Compression test of porous polyurethane/alumina composite (simulated bone) showed a critical porosity of approximately 50 % in both yield strength and Young’s modulus. FEM simulations suggested a compatible critical porosity in stress concentration factors which suggest higher stress. The difference in estimated critical porosities can be attributed to stability of deformation in FEM simulations. A framework of determining optimal pores distribution considering interaction of stress concentration is discussed, and optimization method is then considered.