移动冲击载荷作用下覆冰接触线响应行为研究
STUDY ON RESPONSE BEHAVIOR OF ICED CONTACT WIRES UNDER MOVING IMPACT LOADS
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摘要: 接触网覆冰严重影响电气化铁路的受流质量与运行安全, 机械除冰是目前应用最广泛的手段, 实际作业中除冰装置沿接触线连续移动并施加间歇性冲击, 而现有研究多局限于定点冲击模式, 难以准确解释除冰机理. 本文提出一种移动冲击载荷作用下覆冰接触线机械除冰建模及响应分析方法, 通过建立覆冰接触线精细化有限元模型, 以拉伸破坏准则定义覆冰材料侵蚀失效, 采用LSDYNA非线性有限元显示动力学分析实现冲击载荷作用下接触线除冰过程中的模拟, 重点研究除冰过程中的波传播规律, 探讨了应力波叠加效应与覆冰破坏模式的关联性. 在数值算例部分探讨了不同移动加载次数与模式下覆冰接触线除冰率与接触线动力学响应模式, 给出了能够表征波传播、反射、叠加和除冰率关联的结构位移、应力响应云图, 结果表明: 相较于定点加载模式, 移动加载不仅能够通过应力波的分散传播与叠加提升除冰率, 还能有效控制接触线垂向动态位移的剧烈程度. 本文的相关方法可为机械式除冰装置设计提供参考.Abstract: The phenomenon of catenary icing poses a severe and persistent threat to the current collection quality and the overall operational safety of electrified railway systems. Currently, mechanical de-icing represents the most extensively applied technique in engineering practice. During the actual operation process, the de-icing device moves continuously along the contact line trajectory while simultaneously applying intermittent impacts. However, the majority of existing research studies are limited to the fixed-point impact mode, which makes it difficult to accurately explain the complex de-icing mechanism. This paper proposes a comprehensive modeling and response analysis method for the mechanical de-icing of iced contact lines subjected to moving impact loads. By establishing a refined finite element model of the iced contact line, the erosion failure of the ice material is defined specifically based on the tensile failure criterion. The simulation of the de-icing process under impact loads is realized by adopting LSDYNA nonlinear finite element explicit dynamic analysis. This study focuses on investigating the wave propagation laws during the de-icing process and exploring the correlation between the stress wave superposition effect and the failure modes of the ice layer. In the numerical examples section, the de-icing rate of the iced contact line and the contact line dynamic response patterns under different moving loading times and loading modes are discussed. The study provides structural displacement and stress response contours that are capable of characterizing the relationships among wave propagation, reflection, superposition, and the de-icing rate. The results indicate that, compared with the fixed-point loading mode, the moving loading mode not only significantly enhances the de-icing rate through the dispersed propagation and superposition of stress waves but also effectively controls the severity of the vertical dynamic displacement of the contact line. The relevant methods and conclusions presented in this paper can provide a valuable theoretical reference for the optimization and design of mechanical de-icing devices.
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