X射线衍射法测试高速列车车体铝合金残余应力

摘要

In order to test the surface residual stress in the aluminum alloy carbody of high-speed trains accurately, quickly, and non-destructively, the tensile test of an equal strength rod was used to calibrate the measurement of X-ray diffraction ( XRD) method. The residual stress values of welded joints in the aluminum alloy carbody of a high speed train were detected separately by XRD method, blind hole-drilling method, and finite element method ( FEM) , and then compared with each other. The results show that during the tensile test of the equal strength rod sample, the stress value measured by XRD method well accords with the tensile loading stress in the range of 10 to 70 MPa, and hence the XRD method can be used for testing the residual stress in the key parts of the aluminum alloy carbody of high speed trains. In addition, the numerical values of residual stress detected by XRD method are slightly higher than those obtained by theoretical calculation and electrical measuring method. The maximum residual stress of welded joints in high speed train aluminum alloy vehicle roof is approximately 146. 3 MPa. The residual stress results detected by XRD method are in good agreement with those by the equal strength rod tensile calibration, blind hole-drilling method, and FEM.%为了准确、无损、快速地检测高速列车铝合金的表面残余应力,采用等强杆拉伸试验方法,用X射线衍射法对测试结果进行标定,并用X射线衍射法、盲孔法以及有限元法对测得的车体铝合金焊接接头残余应力进行了对比.结果表明:等强杆拉伸试验标定过程中,在10～70 MPa范围内,随着拉伸载荷的增加,X射线法测得的应力与载荷应力具有一致性,可采用X射线衍射法对车体关键部位应力状态进行测试分析,X射线衍射法残余应力的数值略大于理论计算值和电测法计算值；车顶铝合金焊接接头最大残余应力可达146.3 MPa;X射线衍射法与等强杆标定方法、盲孔法、有限元计算模拟方法的残余应力结果保持了较好的一致性.