油管模型建立及结构对称性对其残余应力影响

Establishment of pipe FEA model and influence of structural symmetry on its residual stress

目前对调距桨传动轴内异种金属焊接油管的残余应力研究很少,油管作为调距浆核心的动力元件之一,其可靠性尤为重要.基于ANSYS有限元软件以四椭球热源模型模拟焊接热输入建立了油管焊接温度场和应力场分析的热-弹-塑性有限元模型,并对该模型进行了试验验证.在此基础上,研究了长焊缝有限计算模型的简化方法和焊件结构的对称性对油管残余应力的影响.结果表明,在保证计算精度的基础上,简化后油管有限元模型的计算速度是未简化模型的8倍.非对称结构油管的残余应力在数值上明显大于对称结构油管的残余应力,在一定程度上非对称结构的油管能够反映对称结构油管最薄弱位置的残余应力分布.

At present, there is barely any research on the residual stress of the pipe welded by dissimilar metals in the drive shaft of the controllable pitch propeller. As the core power elements of the controllable pitch propeller, reliability of the pipe is particularly important. Based on the finite element software ANSYS, the thermal-elastoplastic finite element model for the analysis of the welding temperature field and stress field of the outer pipe was established with a four-ellipsoid heat source model to simulate the welding heat input. The model was verified by experiments. On this basis, the influence of the simplification method of the long weld FE model and the symmetry of the welded structure on the residual stress of the pipe is studied. The research results show that, on the basis of ensuring the calculation accuracy, the calculation speed of the simplified pipe finite element model is 8 times that of the original model. The residual stress of the pipe with asymmetrical structure is obviously greater than that of the pipe with symmetrical structure in numerical value. To a certain extent, the pipe with asymmetrical structure can reflect the residual stress distribution at the weakest position of the pipe with symmetrical structure.