Suspension parameter design of underframe equipment considering series stiffness of shock absorber

Jie Chen,Limin Zhang,Xiaolong He,Yangjun Wu,Shijie Dong

doi:10.1177/1687814020922647

Abstract

In this article, a vertical rigid–flexible coupling model between the vehicle and the equipment is established. Considering the series stiffness of hydraulic shock absorbers, the underframe equipment is like a three-element-type Maxwell model dynamic vibration absorber. The carbody is approximated by an elastic beam and the three-element-type dynamic vibration absorber for general beam system was studied by fixed-point theory. The analytical solution of the optimal suspension parameters for the beam system subjected to harmonic excitation is obtained. The dynamic vibration absorber theory is applied to reduce the resonance of the carbody and to design the suspension parameters of the underframe equipment accordingly. Then, the railway vehicle model was established by multi-body dynamics simulation software, and the vibration levels of the vehicle at different speeds were calculated. A comparative analysis was made between the vehicles whose underframe equipment was suspended by the three-element-type dynamic vibration absorber model and the Kelvin–Voigt-type dynamic vibration absorber model, respectively. The results show that, compared with the vehicle whose underframe equipment is suspended by the Kelvin–Voigt-type dynamic vibration absorber model, the vehicle whose underframe equipment is suspended by the three-element-type dynamic vibration absorber model can achieve a much better ride quality and root mean square value of the vibration acceleration of the carbody. The carbody elastic vibration can be reduced and the vehicle ride quality can be improved effectively using the designed absorber.

Highlights

With the application of lightweight technology in railway vehicles, the weight of the carbody decreases, which leads to a decrease in structural stiffness and reduces the natural frequency of the carbody.[1,2,3] flexible vibration of the carbody under random excitation of the wheel–rail is more likely
In section “Vibration reduction of the flexible carbody,” the effect of the series stiffness of the shock absorber on vehicle vibration is analyzed, and the optimal parameters of three-element-type dynamic vibration absorber (DVA) based on the fixedpoint theory are presented
From equation (29), the results show that the amplitude–frequency curve will pass through three points independent of the damping ratio, that is, the fixed point of the DVA

Summary

Introduction

With the application of lightweight technology in railway vehicles, the weight of the carbody decreases, which leads to a decrease in structural stiffness and reduces the natural frequency of the carbody.[1,2,3] flexible vibration of the carbody under random excitation of the wheel–rail is more likely. Shi et al.[11] established the dynamics model of vehicle system by combining multi-body dynamics theory with finite element method and considered the underframe suspended equipment as DVA to analyze the vibration response of the carbody. In section “Vibration reduction of the flexible carbody,” the effect of the series stiffness of the shock absorber on vehicle vibration is analyzed, and the optimal parameters of three-element-type DVA based on the fixedpoint theory are presented. The structure presented in this article can be expressed as the three-element-type Maxwell model, as shown in Figure 6(b).[17,25] In Figure 6, ce is the damping value of the hydraulic shock absorber, kc is the series stiffness value, and ke is the stiffness value of the suspension system. Two of the points, P and R, are adjusted to the same height

C2 A2 C2 þ þ þ þ

Findings

Conclusion