Stability and dynamic characteristics of a bail bearing-rotor system are investigated under the effect of the clearance in the ball bearing. Different clearance values are assumed to calculate the nonlinear stability ...Stability and dynamic characteristics of a bail bearing-rotor system are investigated under the effect of the clearance in the ball bearing. Different clearance values are assumed to calculate the nonlinear stability of periodic solution with the aid of the Flo- quet theory. Bifurcation and chaos behavior are analyzed with variation of the clearance and rotational speed. It is found that there are three routes to unstable periodic solution. The period-doubling bifurcation and the secondary Hopf bifurcation are two usual routes to instability. The third route is the boundary crisis, a chaotic attractor occurs suddenly as the speed passes through its critical value. At last, the instable ranges for different internal clearance values are described. It is useful to investigate the stability property of ball bearing rotor system.展开更多
We discuss the influence of precipitation and groundwater on the deformation behavior of the Babaoshan fault of Beijing by using long-term observation data from Dahuichang station during 1970-2003. The results show th...We discuss the influence of precipitation and groundwater on the deformation behavior of the Babaoshan fault of Beijing by using long-term observation data from Dahuichang station during 1970-2003. The results show that a) the pore pressure on fault zone as well as the fault deformation behavior exhibited periodically variation as precipitation changed steadily and periodically; b) the periodicity of the pore pressure of fault zones disappeared and the manner of fault deformation behavior changed when precipitation was small and/or was in aberrance. This implies that rainfall plays a key role in fault deformation behavior through changing the pore pressure of fault zones. Combining the existing results about the Babaoshan fault, it is concluded that precipitation and groundwater may adjust the stress/strain field by controlling the deformation behavior of the fault, which can provide direct observation evidence for the interaction of fluid and solid in shallow crust of the Earth.展开更多
基金Project supported by the National Natural Science Foundation of China (No.50275113) and the Doctoral Science Foundation of Ministry of Education (No.20030698017)
文摘Stability and dynamic characteristics of a bail bearing-rotor system are investigated under the effect of the clearance in the ball bearing. Different clearance values are assumed to calculate the nonlinear stability of periodic solution with the aid of the Flo- quet theory. Bifurcation and chaos behavior are analyzed with variation of the clearance and rotational speed. It is found that there are three routes to unstable periodic solution. The period-doubling bifurcation and the secondary Hopf bifurcation are two usual routes to instability. The third route is the boundary crisis, a chaotic attractor occurs suddenly as the speed passes through its critical value. At last, the instable ranges for different internal clearance values are described. It is useful to investigate the stability property of ball bearing rotor system.
基金National Natural Science Foundation of China (40374019)Joint Earthquake Science Foundation of China (1040106).
文摘We discuss the influence of precipitation and groundwater on the deformation behavior of the Babaoshan fault of Beijing by using long-term observation data from Dahuichang station during 1970-2003. The results show that a) the pore pressure on fault zone as well as the fault deformation behavior exhibited periodically variation as precipitation changed steadily and periodically; b) the periodicity of the pore pressure of fault zones disappeared and the manner of fault deformation behavior changed when precipitation was small and/or was in aberrance. This implies that rainfall plays a key role in fault deformation behavior through changing the pore pressure of fault zones. Combining the existing results about the Babaoshan fault, it is concluded that precipitation and groundwater may adjust the stress/strain field by controlling the deformation behavior of the fault, which can provide direct observation evidence for the interaction of fluid and solid in shallow crust of the Earth.
