高速列车铝合金车体强度可靠性安全系数分析方法

ANALYSIS METHOD OF STRENGTH RELIABILITY SAFETY COEFFICIENT FOR HIGH SPEED TRAIN ALUMINUM CARBODY

针对铁道车辆结构设计标准中给定的安全系数存在经验性,从可靠性理论出发,分析可靠性安全系数评估方法,使安全系数选取趋于合理。以某型高速列车车体为研究对象,建立其有限元模型,参照EN12663-1车体设计标准确定静强度载荷工况。并考虑高速会车情况下的气动载荷工况,施加边界条件对车体进行强度分析。同时结合车体铝合金材料性能绘制车体材料的不同可靠度的Goodman曲线,建立可靠度与安全系数的关系模型,对车体静强度和疲劳强度的可靠性安全系数进行了分析。结果表明:随着可靠度的提高,安全系数降低,车体满足不同可靠度下的静强度和疲劳强度要求。99.9%可靠度下静强度的最小安全系数为1.3,出现在整备状态下纵向受1 500 kN压缩载荷作用的工况下;考虑气动载荷影响,结构疲劳安全系数最小值为1.53,有一定的安全裕量,车体侧墙门角和窗角位置的安全系数较小。车体结构的应力和材料强度的分散性对安全系数有影响,为确保高速列车车体具有较高的可靠度,可以采取控制铝合金材料强度性能的分散程度、降低几何结构的应力集中和优化结构减小工作应力等措施来实现。

The safety coefficient given in the design codes of railway vehicle structure has certain experience. In this paper, based on the reliability theory, the method of reliability safety coefficient evaluation is adopted, which makes the selection of safety coefficient more reasonable. A certain type of high speed train carbody was taken as research object, the finite element model was established. Based on the code EN 12663-1, the static and fatigue loads were determined, which is considered the aerodynamic load in condition of high speed passing. After the static strength analysis of carbody, the fatigue strength was analyzed using the reliability Goodman curve of carbody material. Finally, established the relationship of reliability and safety coefficient, the safety coefficient of static strength and fatigue strength of the car body with different reliability were obtained. The results show that the static strength and fatigue strength of carbody meet to the requirement under the different reliability. With the increase of the reliability, the safety coefficient is reduced. The minimum safety coefficient of static strength under reliability of 99.90% is 1.3, and the corresponding load condition is the preparation condition combined with 1 500 kN longitudinal compression load. In aspect of fatigue strength, the locations with small safety coefficient mostly appear in the door’s corner and the window’s corner of the carbody sidewall. The minimum safety coefficient of fatigue strength 1.53, which has a certain safety margin. The dispersion of carbody stress and material strength have influence on the safety coefficient. In order to ensure the high reliability of the high speed train body, it can take measures to control the strength properties dispersion degree of aluminum alloy materials, reduce the stress concentration of the geometrical structure and reduce the working stress and so on.