铁道客车车体刚度与模态关系理论研究

Theoretical Study on the Relationship between Stiffness and Modal of Railway Passenger Car Bodies

[目的]为了分析车体刚度与模态之间的关系,为轻量化后的车体模态分析提供理论支撑,有必要对二者进行理论研究。[方法]以25T型客车车体为研究对象,建立了车体有限元模型,开展车体静动态性能分析,确定了影响车体模态的关键结构。结合车体的几何特征,建立车体板梁混合有限元模型。通过最优拉丁超立方抽样法,获取底架的40组设计变量,计算了不同几何参数下的车体模态和等效刚度。结合车体刚度和模态之间的函数关系,计算和分析了车体轻量化后的车体模态。[结果及结论]车体等效抗弯刚度与等效扭转刚度分别与一阶垂弯模态频率和一阶扭转模态频率呈线性正相关关系。优化后的车体有限元结果表明,车体一阶垂弯模态频率由9.04 Hz提升至9.24 Hz,车体一阶扭转模态频率由15.99 Hz提升至16.66 Hz,符合刚度和模态频率之间的理论关系。

[Objective]To analyze the relationship between carbody stiffness and modal,and to provide theoretical support for the modal analysis of lightweight carbodies,it is necessary to conduct a theoretical study on both aspects.[Method]Taking the 25T passenger vehicle as the research object,a finite element model of the carbody is established.Static and dynamic performance analysis of the carbody is carried out to identify key structures affecting the carbody modal.A carbody plate-beam mixed finite element model is established based on carbody geometric features.Using the optimal Latin hypercube sampling method,40 sets of design variables for the chassis are obtained,and the carbody modal and equivalent stiffness results under different geometric parameters are further calculated.The modal of the lightweight carbody is calculated and analyzed based on the function relationship between carbody stiffness and modal.[Result&Conclusion]The equivalent bending stiffness and equivalent torsional stiffness of the carbody are linearly and positively correlated with the first-order vertical bending and torsional modal frequencies,respectively.The optimized finite element results of the carbody show that the first-order vertical bending modal frequency increases from 9.04 Hz to 9.24 Hz,and the first-order torsional modal frequency increases from 15.99 Hz to 16.66 Hz,which are consistent with the theoretical relationship between stiffness and modal frequency.