Study on Stress Intensity Factors of EMU Hollow Axles
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摘要: 为研究动车组空心车轴应力强度因子,首先分析了车轴应力强度因子的影响因素,建立了含裂纹车轴有限元模型,并使用叠加法求解不同载荷下的应力强度因子。然后采用应力外推法和位移外推法计算了应力强度因子,并将计算结果与文献形状因子公式法进行对比。最后根据应力强度因子的一般解析式和位移外推法的计算结果,使用五次多项式对形状因子函数进行拟合,通过设置不同的裂纹深度和载荷验证了形状因子函数和解析式的适用性。结果表明该方法对于求解同一载荷模式下的车轴应力强度因子具有一定的参考价值。Abstract: In order to study the stress intensity factors (SIFs) for hollow axle of EMU, the influencing factors of the axle SIFs were firstly analyzed. The finite element model for axle with crack was established, and the superposition method was used to evaluate SIFs under different loads. Then, the SIFs were calculated by using the stress extrapolation method (SEM) and displacement extrapolation method (DEM), and the calculation results were compared with that by using the shape factor formula method. Finally, a fifth-order polynomial was used to fit the shape factor function according to the general analytical formula of SIFs and calculation results via DEM. The applicability of the shape factor function and the analytical formula was verified by setting the different crack depths and loads. The results indicated the present method had certain reference value for calculating SIFs of axle under the same load mode.
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表 1 应力强度因子计算结果
Table 1. Calculation results of stress intensity factors
计算方法 位移外推法 应力外推法 KA, Bending/(MPa·m0.5) 3.457 84 2.401 66 KA, PF/(MPa·m0.5) 5.834 95 6.062 21 KA, Tol/(MPa·m0.5) 9.292 79 8.463 87 表 2 形状因子函数拟合常数
Table 2. Constants for fitting the shape factor function
i pi qi 0 9.228×10-1 6.580×10-1 1 2.024×10-2 -3.673×10-3 2 -2.545×10-3 -2.373×10-3 3 1.045×10-4 1.151×10-4 4 -1.864×10-6 -2.155×10-6 5 1.235×10-8 1.446×10-8 -
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