統計力学を応用した破壊靱性値の評価指標に関する研究

概要

論文の詳細を見る
A new parameter, which enable to evaluate the characteristics on fracture toughness quantitatively, e.g. dependence on geometrical shape of specimen and a large scattering under the same experimental condition, is developing in this paper. This parameter represents the intensity of activation free energy in fracture process zone and is a function of strain rate and temperature in the zone. Einstein model of the lattice vibration in solid, which is based on statistical mechanics, is applied to derive the new parameter. Fracture toughness test results under various crack length, ambient temperature and loading rate shows that the scattering and the crack length dependence on fracture toughness can be considerably reduced if the suggested parameter in this paper is used as an evaluation index for fracture toughness. This result indicates that the scattering originates in the difference of strain rate in fracture process zone due to the difference of initial crack length of each specimen, even under static loading condition, and that crack length dependence on fracture toughness can be explained by considering strain rate in the process zone instead of the qualitative concept of plastic constraint effect on fracture toughness.
社団法人日本船舶海洋工学会の論文