摘要
铁路货车密度、载重、速度是提高铁路运输能力的三大要素。目前,大同、秦皇岛运煤专线在已开行2万吨重载列车的基础上即将开行3万吨重载列车。提速、重载以来,C80B等主要货车车体结构先后出现了疲劳裂损,如端墙、心盘梁、侧柱部位的裂纹等,对运输安全有较大的影响,因此在设计阶段考虑疲劳问题能够提高我国货车装备设计技术。
我国货车现行结构强度设计规范和试验标准尚不完善,特别是缺少符合我国实际运用条件的疲劳强度设计规范和试验标准。因此更新我国货车结构的强度设计规范和试验标准,已成为一项非常紧迫的工作,对提升我国货车车体结构的设计水平有重大意义。
本论文以C80B型敞车车体的端墙为研究对象,在20000吨重载列车动应力测试的基础上,对端墙上测点的载荷-时间历程数据进行处理、雨流法计数,分别按照矩形分布和三角形分布,编制了端墙载荷谱;运用Solidworks三维软件建立了C80B车体的实体模型,并运用ANSYS有限元分析软件进行了心盘载荷、纵向载荷和端墙冲击三种载荷工况的应力计算,找到端墙上大应力发生部位;然后分别依据AAR标准和BS EN1993-1-9标准中疲劳损伤的计算方法,采用大秦线2万吨重载列车动应力测试实测的心盘载荷谱、纵向载荷谱和本文编制的端墙载荷谱,进行上述部位的疲劳损伤计算,进而得到它们的累积损伤;最后进行端墙各部位的损伤统计,分别按照AAR标准和BS EN1993-1-9标准估算端墙各部位的疲劳寿命。通过计算分析后发现,端墙支撑梁与中梁的横向和纵向焊缝交汇点的合成损伤最大,约为1.58e-02,其重车寿命为4万公里。其次是端墙支撑梁与中梁横向焊缝,合成损伤约为2.13e-03,疲劳寿命为29万公里。
Density, carrying capability and speed of railway freight cars are the three essential factors to improve the railway transportation ability. At present, Datong and Qinhuangdao special railway lines for carrying coal will travel T30,000 heavy haul trains on the basis of traveling T20,000 heavy haul trains. Since we carried out high speed and heavy load, the C80B and other main vehicle carbody structures appeared fatigue crack damage successively, such as cracks of endwall, heart plate beam and jambs and so on. Consequently, the fatigue problems of vehicle structures become one of the key factors for restricting freight vehicle equipment technology promotion.
Current structural strength design specifications and experimental standards of freight vehicle in our country is still imperfect, especially lacking these fatigue strength design specifications and experimental standards conforming to our actual utilization conditions. So, it's very urgent to update the fatigue strength design specifications of the freight vehicle structure. And it will have great significance for upgrading our country's design level of vehicle carbody structures.
This paper takes the CB0B gondola car endwall of car body as the study object, having processed the load-time history data of measuring points of endwall and carried out the rainflow counting on the basis of the dynamic stress test of the T20,000 heavy haul trains, then compiled load spectrum of endwall according to rectangular distribution and triangle distribution respectively.
On the basis of Solidworks 3-d software, a solid model of C80B carbody was set up. Afterwards, on the condition of center plate loading, longitudinal loading and endwall impacting, the carbody was calculated and got some positions with high stress. Based on calculation methods about fatigue damage of AAR standard and BS EN1993-1-9 Standard respectively, fatigue damage and cumulative damage of above mentioned positions were calculated referring to actual measured center plate load spectrum、longitudinal load spectrum in Datong and Qinhuangdao special railway lines as well as endwall load spectrum compiled. Finally, carried on every position damage statics and carried out fatigue life prediction of endwall in accordance with AAR standard and BS EN1993-1-3 standard separately. Damages about transposition of transverse and longitudinal welding seam between bearing beam of endwall and center sill and transverse welding seam between bearing beam and center sill are the biggest two positions through calculating and analysis, approximately 1.58e-02 and 2.13e-03 separately. Their fatigue life are 40,000 kilometer and 290,000 kilometer respectively.
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