基于不同标准的煤炭漏斗车车体焊缝疲劳寿命研究

Fatigue Life Prediction of Coal Hopper Car Body Weld Based on Different Standards

利用接触非线性分析技术,基于AAR标准的名义应力法和ASME标准的结构应力法研究煤炭漏斗车车体焊缝的疲劳问题。首先,建立漏斗车重载车体强度分析模型,利用修正D-P本构模型的实体单元模拟散粒煤、接触单元模拟散粒煤与车体结构的作用,并通过主要载荷作用下车体静强度试验结果验证车体仿真分析结果,应力最大误差小于15%。其次,运用名义应力法,在标准和实测载荷谱下分析车体焊缝疲劳寿命,结果表明:端墙与端漏斗板焊缝寿命最短,为2.72×10^(6)km;基于标准纵向载荷谱的焊缝寿命小于基于实测的计算结果,表明标准的纵向载荷谱相对恶劣。最后,在标准中100t漏斗车重车心盘载荷谱和实测纵向载荷谱下运用结构应力法对车体焊缝进行应力与寿命分析。结果表明:基于结构应力法的焊缝疲劳寿命不及基于名义应力法的疲劳寿命,主要原因是结构应力法的疲劳性能参数适用于各类接头形式,且分析承载复杂焊缝时考虑了面内剪切结构应力的影响。因此,对接头几何形状和应力状态复杂的车体从板座及底架区域的焊缝建议采用结构应力法对其进行疲劳寿命分析。

Based on the contact nonlinear analysis technology,the fatigue problem of the coal hopper car body weld is studied by using the nominal stress method in the AAR standard and the structural stress method in the ASME standard.Firstly,the strength analysis model of the heavy-duty body of hopper car is established.In the model,the solid element with modified D-P constitutive model is used to simulate the granular coal,and the contact element is used to simulate the interaction between the granular coal and the car body structure.The static strength test results of the car body under the main load verify the simulation analysis results of the car body,and the maximum stress error is less than 15%.Then,the nominal stress method is used to analyze the fatigue life of the car body weld under standard and measured load spectrum.The results show that the weld life of the end wall and end funnel plate is the shortest,which is 2.72×10^(6)km.The weld life based on the standard longitudinal load spectrum is less than that based on the measured spectrum,which shows that the standard longitudinal load spectrum is relatively bad.Finally,the structural stress method is used to analyze the stress and life of the car body weld under the standard 100t hopper car load spectrum and measured longitudinal load spectrum.The results show that the fatigue life of the weld based on the structural stress method is shorter than that based on the nominal stress method.The main reason is that the fatigue performance parameters of the structural stress method are suitable for various joint forms,and the influence of in-plane shear structural stress is considered when analyzing the bearing complex weld.Therefore,the structural stress method is recommended for fatigue life analysis of the welds from the plate base and the chassis area of the car body with complex joint geometry and stress state.