基于本征应变重构技术构造搅拌摩擦焊接铝合金薄板接头的残余应力场

Reconstruction of Residual Stress Field in A Fricition Stir Welding Joint of Aluminium Alloy Plate Based on Eigenstrain Reconstruction Method

采用本征应变重构技术,以小孔法测试的少量应力数据为基础,利用热弹性有限元法构造出4mm厚铝合金搅拌摩擦焊接接头的纵向残余应力场;研究了表征本征应变的多项式阶数和试验数据量对构造残余应力场结果的影响。结果表明:在少量测试数据的基础上对数据进行插值拟合处理,采用10阶以上切比雪夫多项式表征本征应变,可构造出与试验结果符合较好的纵向残余应力场;试验数据需包含特征区域的应力值才能较准确构造出该区域的应力分布。

Based on the eigenstrain reconstruction method and limited measurements with hole-drilling method, the longitudinal residual stress distribution in a friction stir welding joint of 4 mm thickness aluminium alloy plate was reconstructed by the thermal-elastic finite element method. The effects of the order of polynomial and the amount of the experimental data on the constructed residual stress field were also investigated. The results show that the longitudinal residual stress distribution can be well reconstructed from the limited experimental data treated by interpolation fitting based on the eigenstrain reconstruction method with the order of the Chebyshev polynomial larger than 10 to construct the unknown eigenstraira In addition, the constructed stress would be more accurate if the experimental data includes the stresses in the required regions.