A New Application of Multi-Body System Dynamics in Vehicle-Road Interaction Simulation

In vehicle-road interaction simulation, multibody system (MBS) dynamics as well as the corresponding software ADAMS has been employed to model the nonlinear vehicle in more detail. The simulation method has been validated by the test data, and been compared to the former simple models. This method can be used for estimating the effects of dynamic tire forces and other vehicle features on road damage so that the “road-friendliness” can be assessed in vehicle design process.

Railway wheel profile fine-tuning system for profile recommendation

This paper develops a wheel profile fine-tuning system(WPFTS)that comprehensively considers the influence of wheel profile on wheel damage,vehicle stability,vehicle safety,and passenger comfort.WPFTS can recommend one or more optimized wheel profiles according to train operators’needs,e.g.,reducing wheel wear,mitigating the development of wheel out-of-roundness(OOR),improving the shape stability of the wheel profile.Specifically,WPFTS includes four modules:(I)a wheel profile generation module based on the rotary-scaling finetuning(RSFT)method;(II)a multi-objective generation module consisting of a rigid multi-body dynamics simulation(MBS)model,an analytical model,and a rigid–flexible MBS model,for generating 11 objectives related to wheel damage,vehicle stability,vehicle safety,and passenger comfort;(III)a weight assignment module consisting of an adaptive weight assignment strategy and a manual weight assignment strategy;and(IV)an optimization module based on radial basis function(RBF)and particle swarm optimization(PSO).Finally,three cases are introduced to show how WPTFS recommends a wheel profile according to train operators’needs.Among them,a wheel profile with high shape stability,a wheel profile for mitigating the development of wheel OOR,and a wheel profile considering hunting stability and derailment safety are developed,respectively.

Progressive collapse of 2D reinforced concrete structures under sudden column removal

Once a column in building is removed due to gas explosion,vehicle impact,terrorist attack,earthquake or any natural disaster,the loading supported by removed column transfers to neighboring structural elements.If these elements are unable to resist the supplementary loading,they continue to fail,which leads to progressive collapse of building.In this paper,an efficient strategy to model and simulate the progressive collapse of multi-story reinforced concrete structure under sudden column removal is presented.The strategy is subdivided into several connected steps including failure mechanism creation,MBS dynamic analysis and dynamic contact simulation,the latter is solved by using conserving/decaying scheme to handle the stiff nonlinear dynamic equations.The effect of gravity loads,structure-ground contact,and structure-structure contact are accounted for as well.The main novelty in this study consists in the introduction of failure function,and the proper manner to control the mechanism creation of a frame until its total failure.Moreover,this contribution pertains to a very thorough investigation of progressive collapse of the structure under sudden column removal.The proposed methodology is applied to a six-story frame,and many different progressive collapse scenarios are investigated.The results ilustrate the efficiency of the proposed strategy.