基于轮廓法的焊接纵向残余应力三维分布研究

发布时间：2018-08-28 14:39

【摘要】：焊接结构的内部残余应力测试是当前研究的热点和难点。轮廓测试法是近年来被广泛关注的一种残余应力测量新方法。本文采用有限元模拟方法,结合已有数据对轮廓测试法进行理论研究与验证,并且通过固有应变理论与轮廓测试法相结合,提出了一种能够对整个焊接构件内部纵向残余应力的三维分布进行重构的轮廓测试新方法,并对这一方法进行了模拟研究与试验验证。首先,对轮廓测试法的理论进行研究,阐明切割面的轮廓变化与残余应力分布存在的对应关系,通过切割面轮廓的反向施加能够对切面处构件内部的残余应力进行计算。其次,对轮廓测试法的实验过程进行有限元模拟,验证轮廓测试法利用切割面轮廓可以计算出残余应力沿切割面的二维分布,同时借助已有的数据,对轮廓法重构应力的准确性进行验证。在此基础上,针对连续加工的构件,研究给出一种通过切割面轮廓近似计算固有应变,进一步通过有限元模拟实现由固有应变计算整个构件内部残余应力的轮廓测试新方法。对这一方法进行模拟研究,系统分析固有应变轮廓法的计算结果,研究多项式阶数对其的影响。最后,进行轮廓法测量残余应力的试验,研究轮廓法实际应用于焊接试件残余应力测量的工艺问题以及数据的处理方式。以轮廓数据为基础,实现对焊接试件内部残余应力三维分布的重构,并通过与有限元模拟以及小孔法测量的结果进行对比,对重构结果进行系统分析。结果表明本文的固有应变轮廓法可以较准确的对焊接纵向残余应力的三维分布进行计算。焊接残余应力的三维分布很难通过试验获得,通常只有采用数值模拟进行计算,因此这一方法具有一定的科研和工程应用价值。本文对轮廓测试法进行了充分的理论与模拟研究以及试验验证,同时将固有应变理论结合到了轮廓测试法当中,在国内的相关领域研究中具有一定的创新性和借鉴意义。
[Abstract]:The measurement of internal residual stress of welded structures is a hot and difficult point. Profile measurement is a new method of residual stress measurement, which has been paid more and more attention in recent years. In this paper, the finite element simulation method is used to study and verify the contour testing method, and the inherent strain theory is combined with the contour testing method. This paper presents a new method of profile measurement which can reconstruct the three-dimensional distribution of longitudinal residual stress in the whole welded member, and simulates and verifies the method. Firstly, the theory of profile testing method is studied, and the relationship between the profile change and residual stress distribution is clarified. The residual stress in the section can be calculated by the reverse application of the profile of the cutting surface. Secondly, the experiment process of contour testing method is simulated by finite element method, and it is verified that the contour testing method can calculate the two-dimensional distribution of residual stress along the cutting surface by using the profile of the cutting surface, and at the same time, with the help of the existing data, The accuracy of the contour method for stress reconstruction is verified. On the basis of this, a new method for measuring the residual stress of the whole member by the inherent strain is presented by using the contour of the cutting surface to approximate the natural strain and the finite element simulation. The results of the inherent strain contour method are systematically analyzed, and the influence of polynomial order on the method is studied. Finally, the residual stress is measured by contour method, and the process problem and data processing method of the profile method applied to the residual stress measurement of welded specimens are studied. Based on the contour data, the three-dimensional distribution of residual stress in welded specimens is reconstructed and compared with the results of finite element simulation and small hole method, and the reconstruction results are analyzed systematically. The results show that the inherent strain profile method in this paper can accurately calculate the three-dimensional distribution of longitudinal residual stress in welding. The three-dimensional distribution of welding residual stress is difficult to be obtained by experiment, and is usually calculated only by numerical simulation. Therefore, this method has certain scientific research and engineering application value. In this paper, full theoretical and simulation research and experimental verification of contour testing method are carried out. At the same time, the inherent strain theory is combined with contour testing method, which has some innovative and referential significance in the research of relevant fields in China.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG404

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