Analysis of the aerodynamic pressure effect on the fatigue strength of the carbody of high-speed trains passing by each other in a tunnel

Abstract

When two high-speed trains pass through a tunnel, the aerodynamic changes are more complex and drastic than in open air owing to the interference of the tunnel wall and the entry effect. The impact on the carbody fatigue strength is very significant in the fatigue reliability design of the carbody. In this paper, the sequential coupling method was used for the first time to study the effect of pressure waves on the fatigue strength in a large-scale and complex carbody structure. The computational fluid dynamics method was used to calculate and analyze the aerodynamic pressure wave of the intersection of the trains in a long and short tunnel. A full-scale finite element shell model of the carbody structure was established. Then, the time integration method was used to convert the transient pressure wave into the aerodynamic loads bearing by the side wall of the carbody. The inhomogeneous stress concentrations at the restraint points were eliminated by the inertial release method; moreover, a finite element analysis of the carbody was carried out under the combined aerodynamic and mechanical loads. The Goodman fatigue strength curve of the aluminum alloy carbody was drawn. The influence of the aerodynamic load on the fatigue strength of the vehicle body was analyzed and compared under the entry effect of the short tunnel. The results show that the aerodynamic load of the short tunnel has a significant impact on the fatigue strength of the carbody owing to the train's entry effect. The safety factor of the fatigue strength is 15% less than that of the long tunnel aerodynamic load. In this paper, computational fluid dynamics and finite element method were used to analyze and evaluate the impact of the pressure wave on the fatigue strength of the carbody, which is of great reference value in the structural design of the carbody subjected to complex aerodynamic loads.

A review of research into aerodynamic concepts for high speed trains in tunnels and open air and the air-tightness requirements for passenger comfort

“…Thus, the longer the tunnel, the smaller the reflected waves. Yaohui Lu, 40 in his research, shows that pressure waves generated inside long and short tunnels are very different. Short tunnels experience higher pressure waves than long tunnels.…”

“…Maximum positive pressure waves occur near the front nose and negative pressure starts with the end of nose. 40 Train (car body shell) compressibility. A sealed car body may be thought of as slightly compressible.…”

“…Maximum positive pressure waves occur near the front nose and negative pressure starts with the end of nose. 40…”

Methods for calculating aerodynamics inside high-speed railway tunnel lining cracks and predicating stress intensity factors

“…Li et al (2022) discovered a linear relationship between the residual fatigue life of a shield tunnel and the cycles of aerodynamic pressures. Furthermore, researchers have also examined the fatigue damage characteristics of high-speed trains (Lu et al , 2019; Song et al , 2015; Zhou et al , 2019) and auxiliary structures inside tunnels (Wang et al , 2021) under the loading of aerodynamic pressures. However, there is a lack of studies investigating the mechanical behavior of tunnel lining cracks subjected to ICWs.…”

The coupled vibration of train and bridge as high-speed trains meet in crosswind

“…With high-bridge ratio (in some lines even exceeding 90% (He et al, 2017)) as a distinctive feature, it is very likely to encounter the meeting of trains on a bridge. Due to the viscosity of air, the aerodynamic force of high-speed trains changes sharply as they meet (Huang, Li, & Yang, 2019;Lu, Zhang, Zheng, Lu, & Wu, 2018), and the rapid change increases train vibration. The train may derail or even rollover due to strong crosswind during running (Miao, Tian, & Gao, 2010;Hu & Guo, 2009).…”