An analytical model of hydraulic damper was presented in forward flight accounting for pitch/flap/lag kinematic coupling and its nonlinear force-velocity curve. The fourth order Runge-Kutta was applied to calculate th...An analytical model of hydraulic damper was presented in forward flight accounting for pitch/flap/lag kinematic coupling and its nonlinear force-velocity curve. The fourth order Runge-Kutta was applied to calculate the damper axial velocity in time domain. Fourier series based moving block analysis was applied to calculate equivalent linear damping in terms of transient responses of damper axial velocity. Results indicate that equivalent linear damping will be significantly reduced if pitch/flap/lag kinematic coupling introduced for notional model and flight conditions.展开更多
A passive energy-dissipating device, velocity, and displacement dependent hydraulic damper (VDHD), is developed to reduce the seismic response of structure. This device is comprised of a hydraulic jack, check valve, r...A passive energy-dissipating device, velocity, and displacement dependent hydraulic damper (VDHD), is developed to reduce the seismic response of structure. This device is comprised of a hydraulic jack, check valve, relief valve, and throttle valve. The numerical analysis model for SAP2000 nonlinear analysis program is proposed to simulate the energy-dissipating characteristics of VDHD. The analysis results of this model compared with the seismic resistant tests reveal that this proposed model can accurately describe the actual energy-dissipating behavior of VDHD. The efficiency of VDHD is confirmed using this proposed model for carrying out numerical analyses of bare building, building added with bulking resistant bracing (BBR), and VDHD. The energy-dissipating capabilities of VDHD are performing excellent displacement and acceleration control with various ground magnitudes; being an energy absorber to absorb mechanical energy in the structure and resist structural movement; and gathering the advantage of BRB.展开更多
Aiming at the problems existed in the squeeze film damper of the rotating machinery utilizing traditional passive dynamic pressure film bearing, a project of dynamic pressure and static pressure hybrid oil film bearin...Aiming at the problems existed in the squeeze film damper of the rotating machinery utilizing traditional passive dynamic pressure film bearing, a project of dynamic pressure and static pressure hybrid oil film bearing with piezoelectric crystal electrohydraulic active control supply orifice hole is proposed. For this kind of hybrid film bearing, the π film assumption can not hold true. In order to solve the pressure distribution, a new kind of solving method is proposed.展开更多
文摘An analytical model of hydraulic damper was presented in forward flight accounting for pitch/flap/lag kinematic coupling and its nonlinear force-velocity curve. The fourth order Runge-Kutta was applied to calculate the damper axial velocity in time domain. Fourier series based moving block analysis was applied to calculate equivalent linear damping in terms of transient responses of damper axial velocity. Results indicate that equivalent linear damping will be significantly reduced if pitch/flap/lag kinematic coupling introduced for notional model and flight conditions.
基金the Science Council of Taiwan, Chinese Taipei (No. NSC-96-2625-Z-167-001)
文摘A passive energy-dissipating device, velocity, and displacement dependent hydraulic damper (VDHD), is developed to reduce the seismic response of structure. This device is comprised of a hydraulic jack, check valve, relief valve, and throttle valve. The numerical analysis model for SAP2000 nonlinear analysis program is proposed to simulate the energy-dissipating characteristics of VDHD. The analysis results of this model compared with the seismic resistant tests reveal that this proposed model can accurately describe the actual energy-dissipating behavior of VDHD. The efficiency of VDHD is confirmed using this proposed model for carrying out numerical analyses of bare building, building added with bulking resistant bracing (BBR), and VDHD. The energy-dissipating capabilities of VDHD are performing excellent displacement and acceleration control with various ground magnitudes; being an energy absorber to absorb mechanical energy in the structure and resist structural movement; and gathering the advantage of BRB.
文摘Aiming at the problems existed in the squeeze film damper of the rotating machinery utilizing traditional passive dynamic pressure film bearing, a project of dynamic pressure and static pressure hybrid oil film bearing with piezoelectric crystal electrohydraulic active control supply orifice hole is proposed. For this kind of hybrid film bearing, the π film assumption can not hold true. In order to solve the pressure distribution, a new kind of solving method is proposed.
