This paper considers the effects of damage softening and hydraulic softening on fault zone media and provides a nonlinear mechanics model of fault earthquake. Taking far field displacement,stiffness ratio and permeati...This paper considers the effects of damage softening and hydraulic softening on fault zone media and provides a nonlinear mechanics model of fault earthquake. Taking far field displacement,stiffness ratio and permeation parameter as control variables, we obtain a swallowtail type catastrophic model of earthquakes. Then, by this model, we study the effects of permeation, far field displacement and stiffness ratio on the preparation and the occurrence of earthquakes.展开更多
High-entropy alloys(HEAs) have attracted considerable attention in recent years because of their unique mechanical properties.In this work, the mechanism of dynamic shear banding(also called adiabatic shear bands, ASB...High-entropy alloys(HEAs) have attracted considerable attention in recent years because of their unique mechanical properties.In this work, the mechanism of dynamic shear banding(also called adiabatic shear bands, ASBs) in a BCC HEA HfNbZrTi was investigated combining dynamic experiments and numerical simulations. The temperature evolution during dynamic shear banding, which has been believed to play a dominant role during ASB formation in the literature, was measured using high-speed infrared thermal detectors synchronized with a split Hopkinson pressure bar system. The dynamic mechanical behavior of the BCC HEA was described using the Johnson-Cook model accompanied by damage accumulation. The process of ASB formation,considering potential contributions from thermal softening and damage softening, was numerically investigated by controlling the activation of each softening mechanism separately. Based on the results of experimental observation and numerical analysis,dynamic shear banding in this BCC HEA is proposed to be dominated by damage softening, and thermal softening only plays a secondary role, which differs from the thermal-softening-dominated ASB formation in typical FCC HEAs such as the Cantor alloy.展开更多
文摘This paper considers the effects of damage softening and hydraulic softening on fault zone media and provides a nonlinear mechanics model of fault earthquake. Taking far field displacement,stiffness ratio and permeation parameter as control variables, we obtain a swallowtail type catastrophic model of earthquakes. Then, by this model, we study the effects of permeation, far field displacement and stiffness ratio on the preparation and the occurrence of earthquakes.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11922202,12002050,and 11802029)the National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact (Grant No. 6142902200401)the Beijing Institute of Technology Research Fund Program for Young Scholars。
文摘High-entropy alloys(HEAs) have attracted considerable attention in recent years because of their unique mechanical properties.In this work, the mechanism of dynamic shear banding(also called adiabatic shear bands, ASBs) in a BCC HEA HfNbZrTi was investigated combining dynamic experiments and numerical simulations. The temperature evolution during dynamic shear banding, which has been believed to play a dominant role during ASB formation in the literature, was measured using high-speed infrared thermal detectors synchronized with a split Hopkinson pressure bar system. The dynamic mechanical behavior of the BCC HEA was described using the Johnson-Cook model accompanied by damage accumulation. The process of ASB formation,considering potential contributions from thermal softening and damage softening, was numerically investigated by controlling the activation of each softening mechanism separately. Based on the results of experimental observation and numerical analysis,dynamic shear banding in this BCC HEA is proposed to be dominated by damage softening, and thermal softening only plays a secondary role, which differs from the thermal-softening-dominated ASB formation in typical FCC HEAs such as the Cantor alloy.
