Research Paper Transient dynamic behaviour of ﬁnite element tire traversing obstacles with diﬀerent heights Chongfeng Wei ⇑ , Oluremi Ayotunde Olatunbosun School of Mechanical Engineering, University of Birmingham, Birmingham B15 2TT, UK Received 19 February 2014; received in revised form 30 June 2014; accepted 1 July 2014 Abstract Tire models used in vehicle dynamics simulation for CAE durability and ride comfort assessment need to be capable of predicting the non-linear deformation and enveloping characteristics which occur when traversing large road obstacles. Normally, transient dynamic characteristics of a rolling tire are determined from tire rig tests, and the tire parameters are transferred into multi-body system for vehi- cle dynamic analysis. However rig design limitations mean that tests cannot be carried out in the most severe conditions, particularly for traversing high ramp or large obstacles. However, using detailed FE tire models, such tests can be carried out virtually. A FE tire model was developed speciﬁcally for this purpose using explicit integration in ABAQUSe. Tire enveloping tests in traversing obstacles of dif- ferent sizes were then carried out, virtually, using the validated FE tire model. Satisfactory results of transient responses were obtained by comparison with the experimental tests for the tire traversing obstacles with diﬀerent heights. Tire transient dynamic behaviour was investigated by analysing the inﬂuence of tire rolling velocity and height of road obstacle on transient spindle responses, dynamic stiﬀ- ness, together with tire deformation for the tire impacting obstacles. Finally, the investigation showed that longitudinal dynamic stiﬀness decreases when the tire traverses a higher obstacle. In addition, with the increase of height of road obstacle, the resonant amplitude of spindle force response as well as the tire deformation becomes larger in both longitudinal and vertical directions, especially for the tire rolling over 25 mm  25 mm rectangular obstacle. Also, it is found that higher travelling velocity of the tire leads to higher resonant amplitude of spindle forces in the vertical direction. Ó 2014 ISTVS. Published by Elsevier Ltd. All rights reserved. Keywords: Transient dynamics; Road obstacle; Explicit program; FE tire model 1. Introduction As a unique component of the vehicle connecting road and the car body, tires play an important role in reducing the eﬀect of road irregularities by attenuating the forces transmitted to the vehicle suspensions. It is of great impor- tance to accurately predict the transient dynamic behaviour of the tire in traversing large obstacles under diﬀerent operating conditions, in order to provide tire designers and researchers with a fundamental understanding of aspects of tire behaviour in ride comfort assessment and vehicle durability analysis under such extreme tire/obstacle interaction. Therefore, tire models used in CAE vehicle dynamics simulation for durability and ride comfort assess- ment need to be capable of predicting the non-linear defor- mation and enveloping characteristics which occur when traversing large road obstacles. However, there are great challenges for predicting the transient dynamic responses of the tire traversing obstacles with acceptable accuracy in the numerical simula- tions because of the diﬃculties arising from modelling http://dx.doi.org/10.1016/j.jterra.2014.07.001 0022-4898/Ó 2014 ISTVS. Published by Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Address: School of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. Tel.: +44 (0)121 414 4167. E-mail address: cxw103@bham.ac.uk (C. Wei). www.elsevier.com/locate/jterra Available online at www.sciencedirect.com ScienceDirect Journal of Terramechanics 56 (2014) 1–16 Journal of Terramechanics