考虑弹性的高速旋转轮对振动特性研究
杨光 任尊松 孙守光
摘要: 轮对弹性变形和旋转振动对轮轨系统运行安全性影响需要从理论上进行深入研究。利用ANSYS有限元分析软件对轮对弹性化处理后,在SIMPACK多体动力学软件中建立了包含高速旋转弹性体轮对的车辆系统动力学模型。采用数值方法,得到了轮轴弹性弯曲变形量以及不同轨道不平顺激扰下轮对垂向振动加速度响应等。结果表明,考虑弹性和旋转振动后,轮对车轴发生弯曲变形效应明显且中部变形量最大,车辆运行速度对车轴弯曲变形量和轮轨附加动力有一定的影响,轮对垂向振动加速度频谱出现与旋转速度相关的频率特征。本文方法和结果对揭示轮对真实运动特征和研究高速轮轨安全性具有良好的指导意义。关键词: 弹性轮对; 高速列车; 旋转; 频率特征
中图分类号: U260.331+.1文献标志码: A文章编号: 10044523(2016)04071406
DOI:10.16385/j.cnki.issn.10044523.2016.04.019
引言
近年来,中国稳步发展高速铁路,高速动车组运营速度已到达300 km/h。作为列车走行的关键部件,高速旋转轮对运用安全性受到了高度关注与重视,亟需在高速范围内,对旋转轮对发生弹性变形后引起的轮轨接触、走行关系、轮轨附加动力以及车辆系统振动和运行安全性等问题开展深入研究。传统车辆动力学研究工作中,轮对一般考虑为刚体或者轮对仅向前做平移运动,无法体现出轮对高速旋转过程中的弹性变形及其对结构振动的影响。近年来,国内外关于轮对弹性化后车辆系统振动特性的研究逐渐增多。万鹏等[1]分别将轮对考虑为刚性和弹性建立整车模型,得到了轮对弹性化处理以后车辆临界速度较刚性轮对的值有所降低的结论;张永贵[2]研究发现,在针对轮轴振动特性的分析中,采用弹性轮对比采用刚性轮对时得到的计算更加准确,也更符合实际情况;马卫华等[3]通过加大轮轴弯曲刚度来改善轮对的垂向振动和轮轨垂向力,以实现改善轮轨动态接触状态的目的;张宝安[4]提出弹性轮对的结构振动对轮轨接触点位置,蠕滑率蠕滑力和脱轨因数等均产生较明显的影响;刘韦等[5]研究表明,轮对考虑为弹性体将会更加准确地反映出车轮多边形化对轮轨力的影响;Baeza L等[6]对比分析弹性旋转轮对模型和刚性轮对模型在车轮扁疤,轨道不平顺激扰下的轮轨力差异。但是,在既有研究中,对于轮对弹性化处理以后,车轴弹性弯曲变形对高速旋转轮对自身振动特性方面的研究尚未涉及。
有鉴于此,本文以某型高速动车组为对象,研究弹性轮轴弯曲变形特征,并进一步分析弯曲变形对高速旋转轮对振动特性的影响。为避免弹性构架[7]和弹性车体[89]对轮对垂向加速度频率成分的影响,这里仅将轮对处理为弹性体,建立刚弹耦合车辆系统动力学模型。
Abstract: Further theoretical studies are needed about the influences of elastic deformation and rotation vibration of wheelset on the wheelrail system operation safety. The railway vehicle system with the highspeed rotating wheelsets which were considered as elastic bodies with the FEM is established in the SIMPACK software. With the numerical method, the degree of bending deformation of the axle is achieved while the wheelset was considered as the elastic body, and the vertical vibration acceleration response of the wheelset under different rail irregularity excitation is also obtained in this paper. The results show that, while considering the elastic and rotation vibration, the axle bending deformation effects are obvious, and the maximum deformation occurs in the center. The degree of bending deformation and the additional force of wheel rail are affected by the vehicle operation speed. The frequency characteristic associated with the speed of rotation appears in the spectrum of vertical acceleration of the wheelset. The methods and the results in this paper have guiding significance to the real characteristics of the wheelset rotation and the studies on the highspeed wheel rail safety.
Key words: elastic wheelset; highspeed train; rotation; frequency characteristics