Horizontal vibration response analysis of ultra-high-speed elevators by considering the effect of wind load on buildings

At present, the wind-induced vibration effects of super-high-rise buildings caused by wind loads can no longer be ignored. The wind-induced vibration effect of super-high-rise buildings will inevitably cause the vibration of ultra-high-speed elevators. However, for the study of the vibration characteristics of ultra-high-speed elevators, the wind-induced vibration effect of the ultra-high-speed elevator is often ignored. Based on Bernoulli–Euler theory, the forced vibration differential equation of elevator guide rail was established, and the vibration equation of elevator guide shoe and car was established by using the Darren Bell principle. The coupled vibration model of the guide rail, guide shoes, and car can be obtained through the relationship of force and relative displacement among these components. Based on the model, the effects of wind pressure and building height on the horizontal vibration of the ultra-high-speed guideway and passenger comfort were analyzed. The results showed that the influence of the wind load on the vibration of ultra-high-speed elevator can no longer be disregarded, and the maximum horizontal vibration acceleration of the guide rail is positively correlated with the height of building. The vibration acceleration of the same height rail increases with the increase in wind pressure. The vibration dose values (VDVs) increase with the increase in wind pressure and building height, respectively.

Research on the vibration model and vibration performance of cold orbital forging machines

The vibration of cold orbital forging (COF) machines is a major issue for the quality of forging parts. It is therefore necessary to investigate the vibration of COF machines and provide some effective methods for reducing the vibration. In this paper, horizontal and vertical dynamic models of COF machines are established. These dynamic models are then effectively verified by conducting experiments. By using dynamic models of the COF machine, the vibration performance of the COF machine is investigated. To investigate methods for reducing the vibration of the COF machine, the effects of some key parameters on the vibration of the COF machine are studied, which include the eccentricities and rotation angular speeds of the inner eccentricity ring and the outer eccentricity ring, the amplitude and frequency of external excitation, and the equivalent stiffness and equivalent damping between swing shaft and bearing. Investigative conclusions can be drawn: During the COF process, vertical vibration is more drastic than horizontal vibration. A larger absolute difference between the eccentricities of the inner eccentricity ring and the outer eccentricity ring contributes to reducing the horizontal vibration of the COF machine. A larger equivalent stiffness and a larger equivalent damping between the swing shaft and bearing, a smaller amplitude and a smaller frequency of the external excitation contribute to reducing the vertical vibration of the COF machine.

High-speed elevator car horizontal vibration fluid–solid interaction modeling method

High-speed elevator horizontal vibration seriously affects passenger comfort. To reach the smooth operation of the high-speed elevators, it is extremely important to study the horizontal vibration of the elevator car. There are two main factors that cause the horizontal vibration of the high-speed elevator car, namely, the guidance system excitations and the car aerodynamic characteristics running in the hoistway. Under the coupling action of these two factors, the horizontal vibration of the high-speed elevator car system is aggravated. To accurately obtain the horizontal vibration information of the high-speed elevator, we developed the high-speed elevator car horizontal vibration fluid–solid interaction model. It is decoupled by the proposed fluid–solid interaction decoupling solution. The influence of the high-speed elevator running speed, the guide rail profile deviation, and the rolling guide shoe dynamic parameters on the car horizontal vibration is analyzed. To verify the feasibility of the proposed method, the 5 m/s, 7 m/s, 8 m/s, and 10 m/s high-speed elevators are applied in a 288 m test tower. The simulation accuracy using the proposed method reaches the minimum of 0.93% in 5 m/s case of the peak-to-peak value, reaches the minimum of 3.11% in 10 m/s case of the A95 value, and reaches the minimum of 0.13% in 10 m/s case of the main frequency value. In general, the compared results of the peak-to peak vibration acceleration, the A95 value, and the main frequency are all closed in both 5 m/s, 7 m/s, 8 m/s, and 10 m/s cases.