Abstract: Proper boundary condition is the key process of the finite element analysis of axle. The point is to meet conditions that axle bears load in simply-support beam mode and constraint boundary should not lead to impractical local high stress areas. On the basis of the analysis of four common shaft constraint method, auxiliary support method and RBE3 multi-point constraints method were proposed, which can satisfy the accuracy requirements of deformation and stress analysis of axle better. The test conditions of auxiliary support method were very close to axle test, and RBE3 method had the feature of less sensitive to the border mesh. According to analyzing the trailer axle, the influence on calculation results of all boundary models was comparative studied.

Key words: vehicle engineering, rigid vehicle axle, simple-support mode, shaft-head constraint method, auxiliary support method

摘要： 车桥有限元分析的关键在于施加正确的位移边界条件，重点是满足车桥的“简支梁”承载模式和约束边界不应导致局部不合理的高应力区等条件。在分析讨论常见的4种轴头约束法的基础上，提出了辅助支承法和RBE3多点约束法两种位移边界建模方法，可以很好的满足车桥变形和应力分析的精度要求。辅助支承法与车桥试验条件比较接近，而RBE3多点约束法具有对边界网格剖分不敏感的特点。通过一个挂车车轴实例分析，对比研究了各种边界模型对计算结果的影响。

关键词: 车辆工程, 整体式车桥, 简支梁承载模式, 轴头约束法, 辅助支撑法