【作者】 周张义；

【导师】 李芾；

【作者基本信息】 西南交通大学 ， 城市轨道交通技术与装备， 2009， 博士

【摘要】 为适应我国快速发展的铁路运输形势,尽快开行满足运行速度为120-160km/h甚至更快的高速货物列车已势在必行。高速货车的开发成为最重要的研究课题之一,而转向架研制则是其核心技术。分析表明,焊接构架式转向架是我国高速货车必然采用的走行部技术模式,而其关键承载部件焊接构架和摇枕的疲劳强度性能,将直接决定着车辆在使用寿命期限内的运行安全性和可靠性。当前国内铁道车辆行业缺乏对动态承载焊接钢结构疲劳强度的系统深入研究,而大量运营实践表明车辆焊接部件的疲劳破坏问题已十分严重,工程上迫切需要对其机理的深入研究,应用更为实用的疲劳工程分析技术解决业已出现的各类问题。鉴于此,论文结合国家科技支撑计划项目,以我国最新开发研制的160km/h高速货车转向架焊接承载部件为目标研究对象,主要在以下三个方面进行了系统研究：1.动态承载焊接钢结构的疲劳工程分析技术研究；2.高速货车转向架焊接部件的疲劳设计载荷和强度评定准则研究：3.高速货车转向架焊接构架及摇枕的疲劳强度分析评定研究。首先针对焊接钢结构的疲劳工程分析技术,论文主要在回顾总结和深入分析国际上以往及当前最新研究成果基础上,对三种适于工程应用的焊接结构疲劳分析方法：名义应力法、表面外推热点应力法和Battelle热点应力法,以及四类关键疲劳影响因素：焊接残余应力、低应力范围循环、多轴应力和焊后改进工艺,进行了全面的系统和深入研究,总结提出了工程实际中各疲劳分析方法的合理应用方式及各疲劳影响因素的合理修正准则。其次论文在对比分析现有多种方法基础上,明确了两类基于强度试验规范的转向架焊接承载部件疲劳设计载荷确定方法,在现阶段工程应用中最为实用,并进一步探讨了其亦存在的局限性及在不同线路条件下的适用性。在对高速货车转向架焊接构架及摇枕结构不同部位的实际承载特点进行深入分析,以及对载荷确定相关因数的疲劳损伤影响规律和程度进行系统研究基础上,论文综合并合理改进了以上两类方法,确定出了高速货车转向架焊接承载部件的疲劳设计载荷及强度评定准则。最后基于论文总结的三类焊接结构疲劳工程分析方法、各关键疲劳影响因素修正准则、确定的疲劳设计载荷及强度评定准则,依据具体情形选择合适的方法完成160km/h高速货车转向架焊接构架和摇枕的疲劳强度分析,进而依据评定结果提出了结构优化设计和焊接制造工艺改进方案。通过将理论计算结果与样机疲劳试验结果进行必要比较,并结合当前转向架焊接承载结构的运用实践,验证了论文分析方法的可靠性和优越性。更多还原

【Abstract】 In order to fit the fast development of Chinese railway transportation, it is imperative that the high-speed freight trains, of which the running speed is 120-160 km/h or more high, should be operated as soon as possible. The development of high-speed freight car is one of the most important reseach items and the bogie is its core technique. It is indicated that welded frame bogie is the certain running gear technique mode for Chinese high-speed freight car. The fatigue strength of welded frame and bolster, which is the key loaded componets of bogie, directly influences the running security and reliability of the car in its life span.Currently, the systemic and deep research on fatigue strength of dynamically loaded welded steel structures are lacking in Chinese rolling stock applications. But it’s indicated from the numerous running practices that the fatigue failure problems of car welded components have been very serious, so it is imperative that deep research on its mechanism should be done and practical fatigue analysis methods should be used to solve the problems occurred. Thus in this paper, combining with the national science and technology pillar program and aiming at the study of welded components for 160km/h high-speed freight car bogie which has been developed newly, the following three aspects were investigated systemically:1. Research on the project fatigue analysis technique for dynamically loaded welded steel structures;2. Research on the fatigue design loads and assessment criteria for welded components of high-speed freight car bogie;3. Research on the fatigue strength analysis and assessment for welded frame and bolster of high-speed freight car bogie.Firstly, based on systemically reviewing, summarizing and analyzing the former and latest international research results, three fatigue analysis approaches which is propitious to project applications for welded structures, including nominal stress method, surface extrapolation hot spot stress method and Battelle hot spot stress method, and four key fatigue effect factors including welding residual stresses, low stress range cycles, multiaxial stresses and post weld improvement techniques were studied roundly and profoundly. For practical project applications, the sound application manner of different fatigue analysis approaches and the rational modification criteria of various fatigue effect factors were discussed and summarized.Secondly, by comparing different methods, it’s included that for bogie welded components, two types of fatigue design loads defining methods based on strength testing codes are most practical in current project applications. Farthermore the limitations of both methods and their applicability while using in different line conditions were discussed. By detailedly analyzing the actual loading characteristic of different structural positions on welded frame and bolster for high-speed freight car bogie, and systemically investigating the fatigue damage effecting pattern and extent of relevant loads defining factors, the two above loads defining methods were improved and colligate reasonably. Then the fatigue design loads and strength assessment criteria for welded components of high-speed freight car bogie were determined.Finally, based on the three project fatigue analysis methods for welded structures, the rational modification criteria of various fatigue effect factors, the fatigue design loads and strength assessment rules summarized or determined in this paper, the fatigue strength analysis of welded frame and bolster for 160km/h high-speed freight car bogie were carried out. And according to the assessment results, the improved scheme for structural optimization design and welding technology were presented. By comparing the theoretical calculating results with the prototype fatigue testing results and combining with the current running practices of bogie welded loaded components, the reliability and advantage of the methods presented in this paper were validated.更多还原