弹性支承块轨道结构落轴冲击动力性能分析

将轮轨接触边界条件用罚函数法释放,采用点面接触单元导出轮轨接触有限元控制方程,建立轨道结构落轴冲击动力有限元方程。分析落轴冲击对轨道结构产生的动态响应,比较弹性支承块及短轨枕埋入式整体道床轨道结构的动力性能,并用现场实测数据进行验证。结果表明:弹性支承块轨道结构与普通短轨枕结构相比,其轨下及块下刚度易于调整,可进行双层弹性的合理匹配,从而有效吸收轮轨冲击,提高列车运行平稳性,具有减振降噪与延缓轮轨磨损等优越性能。建议其块下刚度稍大于轨下刚度,增幅值控制在20%以内。

Analysis on the Dynamic Characteristics of Low Vibration Track by Use of Wheel Load Drop

According to the virtual displacement principal for contact-impact problems,the equation on(calculus) of variations about wheel-rail contact is developed as its determined boundary conditions being released based on penalty function method.Depending on the contact control as well as the track dynamic equation of FEM deduced from the point-to-surface contact element,the dynamic response is simulated and calculated for railway structure impacted by the falling wheel-set.The track dynamic characteristic,which is verified by the on-the-spot experiment,is compared between the Low Vibration Track(LVT) and the short sleeper buried ballastless track.The results show that the LVT,which is superior to the short sleeper buried track in the performance of vibration and noise reduction as well as wheel-rail wear retarding,will absorb the wheel-rail impact and improve the vehicle running stability more effectively as the stiffness under the rail and elastic block being matched properly.It is suggested that the stiffness under the elastic block should be larger than the stiffness under the rail and the increment be less than 20%.