Since the Great Hanshin Earthquake in 1995, many investigations on the seismic damper have been made. On the other hand, it also theoretically projected that ultra fine grained Zn-Al alloys could show superplasticity ...Since the Great Hanshin Earthquake in 1995, many investigations on the seismic damper have been made. On the other hand, it also theoretically projected that ultra fine grained Zn-Al alloys could show superplasticity at low temperatures [1-4]. Authors tried to make a massive ultra fine grained Zn-22 mass % Al alloy by means of TMCP (thermo-mechanical controlling process). The superplastic Zn-Al alloy is not susceptible to strain deterioration because it has a low work-hardening rate and, thus, does not accumulate strain significantly when deformed plastically. On the other hand, since its work hardening rate is low, plastic deformation proceeds locally, required plastic energy can’t be sufficiently obtained and local fracture and local deformation instability can take place easily. The structural designer must overcome the strain localization resulting from the low work-hardening rate. Several types of seismic dampers were successfully developed with overcoming the local deformation instability. Three types of seismic dampers were finally developed.展开更多
In this paper,research of aftershock mechanisms is reviewed,including heterogeneity of medium and stress,mechanical loading,fluid intrusion and stress corrosion,and ratestate dependence.Previous studies have indicated...In this paper,research of aftershock mechanisms is reviewed,including heterogeneity of medium and stress,mechanical loading,fluid intrusion and stress corrosion,and ratestate dependence.Previous studies have indicated that the heterogeneity of media and stress is the basic premise of aftershocks generated.From the point view of mechanics,transient creep and afterslip can explain the decay of aftershocks in a short time after a mainshock and the relaxation of stress tends to interpret the characteristics of long-term aftershocks.Fluid intrusion and stress corrosion control the evolution process of the aftershocks under certain conditions.The interaction between the faults perturbed by the mainshock always exists during the aftershock activities.All kinds of models and the theories want to comply with the two basic power-law relationships---the G-R law and Omori law to some extent.展开更多
文摘Since the Great Hanshin Earthquake in 1995, many investigations on the seismic damper have been made. On the other hand, it also theoretically projected that ultra fine grained Zn-Al alloys could show superplasticity at low temperatures [1-4]. Authors tried to make a massive ultra fine grained Zn-22 mass % Al alloy by means of TMCP (thermo-mechanical controlling process). The superplastic Zn-Al alloy is not susceptible to strain deterioration because it has a low work-hardening rate and, thus, does not accumulate strain significantly when deformed plastically. On the other hand, since its work hardening rate is low, plastic deformation proceeds locally, required plastic energy can’t be sufficiently obtained and local fracture and local deformation instability can take place easily. The structural designer must overcome the strain localization resulting from the low work-hardening rate. Several types of seismic dampers were successfully developed with overcoming the local deformation instability. Three types of seismic dampers were finally developed.
基金sponsored by the National Key Technology R&D Program of China(2012BAK19B0205)Key Foundation of Earthquake Administration of Shandong Province(JJ1308Y)
文摘In this paper,research of aftershock mechanisms is reviewed,including heterogeneity of medium and stress,mechanical loading,fluid intrusion and stress corrosion,and ratestate dependence.Previous studies have indicated that the heterogeneity of media and stress is the basic premise of aftershocks generated.From the point view of mechanics,transient creep and afterslip can explain the decay of aftershocks in a short time after a mainshock and the relaxation of stress tends to interpret the characteristics of long-term aftershocks.Fluid intrusion and stress corrosion control the evolution process of the aftershocks under certain conditions.The interaction between the faults perturbed by the mainshock always exists during the aftershock activities.All kinds of models and the theories want to comply with the two basic power-law relationships---the G-R law and Omori law to some extent.
