脆性材料の時間に依存する変形と強度に関する研究

抄録

It is well-known that brittle materials such as rocks show time-dependent deformation, and there are a lot of papers which deal with the creep phenomenon and mechanism of such materials. These time-dependent, visco-elastic phenomena, however, have mainly been studied from a phenomenal standpoint Some of them show the fact that the creep is caused by the existence and occurrence of micro-cracks and the extension of them from the experiments detecting the acoustic emission. Furthermore, it is well-known that the time-dependent deformation of brittle materials is closely related to fracturing.
fracturing. The authors have tried to simulate the time-dependent deformations of brittle materials caused by extending numerous inner micro-cracks on the basis of linear fracture mechanics by applying the finite element method. The results of this simulation fairly resemble an actual behavior of hard rocks concerning their time-dependent deformation.
In conclusion, it has become clear that the tertiary creep of brittle materials to be connected with the rupture is due to rapid extension of inner cracks, and that the reason that the compressive strength of such materials is extremely greater than the tensile strength is mainly ascribed to the internal friction which acts so as to obstruct the extension of such cracks.