预应力下接触网腕臂结构动态特性研究
Dynamic characteristics study of cantilever structure of OCS under pre-stressed condition

利用有限元软件ABAQUS研究钢腕臂结构在最大工作载荷下的变形量和应力分布情况，对比分析腕臂结构在不同预应力下的前十阶模态振型。采用谐响应分析法计算腕臂结构在不同预应力下的共振频率。研究结果表明：在最大工作载荷作用下，腕臂结构的最大应力出现在定位器与定位器支座接触位置，因此，该区域在服役过程中有可能出现严重的应力集中和材料磨损现象。当对腕臂结构施加预应力时，腕臂结构的低阶模态频率相比于无预应力状态下有明显增大，但其模态振型并不会发生变化。此外，谐响应分析结果表明，预应力的存在能够有效抑制腕臂结构沿铁路线方向(Y方向)的振动。以上研究结果可为新型腕臂结构的设计优化提供指导。
In this study, the deformation and stress distribution of cantilever structure of overhead contact system (OCS) were analyzed under maximum working load by using finite element software (ABAQUS). Accordingly, the first ten natural frequencies and their corresponding modes under different pre-stress working conditions were calculated. Furthermore, the resonance frequency was obtained by using the harmonic response method, to evaluate the stability of the cantilever structure. Results show that the maximum stress of the steel cantilever structure concentrates on the contact position of steady arm and steady arm supporter, which may consequently cause the unwanted material wear and damage generated in this area during working process. The lower-order model frequencies show significant variation when the cantilever structure is applied to different pre-stresses, while the mode sharps show on visible variation. Moreover, results obtained from the harmonic response method indicates that the existence of the pre-stress can significantly suppress the vibration of cantilever structure along the railway line (-Y) direction. These results can provide important engineering guidance for design and optimization of the cantilever structure