A comparison of crosswind calculations using a full vehicle and a simplified 2D model

Abstract

High-speed vehicles are exposed to crosswinds that can result in the overturning of the vehicle. As part of the vehicle homologation process, the characteristic wind curve (CWC) must be calculated to determine the maximum vehicle velocity under different wind conditions. European Standard EN 14067-6 presents different approaches for studying this matter, from a two-dimensional (2D) model to a full multi-body model. The key to the problem rests in the uncertainties inherent in a multi-body model: characterizing its suspension elements and obtaining its aerodynamic coefficients. This paper compares a 2D model with a multi-body model of the same vehicle, and presents the advantages and disadvantages of each one. Results show that a 2D model is valid for graphing the CWC and sufficient for studying the basics of the overturning process. Furthermore, a wheel unloading time signal is also studied. It is concluded that the simplification process can modify the transitory response but that the maximum wheel unloading remains constant. Finally, a study of the wheel/rail contact is performed to check if the contact model has an influence on the calculation of the CWCs.

Experimental investigation of the effects of embankment scenario on railway vehicle aerodynamic coefficients

“…Two international standards for railway vehicles issued in recent years EN 14067-6 (2010) and TSI HS RST (2008), have specific sections on cross-wind safety. The approach to evaluating the cross-wind stability of a railway vehicle described in these two standards, but also in a number of national standards, is based both on the determination of vehicle aerodynamic coefficients using (preferably) wind tunnel tests or CFD calculations, and on the evaluation of the maximum cross-wind speeds at which a vehicle reaches its safety limits, that is the Characteristic Wind Curves (Cheli et al, 2004(Cheli et al, , 2012Carrarini, 2007;Sesma et al, 2012;Baker, 2010b;Ding et al, 2008;Diedrichs, 2003;Tomasini and Cheli, 2013).…”

Rail vehicle response to lateral carbody excitations imitating crosswind

“…2 The work presented in Alfi et al 3 showed the influence of an actively controlled secondary suspension on simulated vehicle response to wind loads represented by a lateral force as well as roll and yaw moments. A comparison between different modelling approaches to investigate the crosswind stability of a rail vehicle was presented in Sesma et al 4 In addition, crosswind stability is a design criterion for rail vehicles, regulated by standards and laws, see for example, [5][6][7] where unsteady crosswinds are taken into account.…”

A framework for the consideration of the effects of crosswinds on trains

“…calculation. This comment is reinforced by the recent work ofSesma et al (2011). They studied the difference between simplified models of trains in cross winds and full MBS simulations.…”