Ti_2AlNb合金薄壁壳体多道次强旋成形有限元模拟

Finite Element Simulation of Multi-pass Power Spinning of Thin-walled Ti_2AlNb Alloy Shell

针对Ti_2AlNb合金旋压加工的实际工况与特点,基于有限元软件的动态、显式模块建立了Ti_2AlNb合金薄壁壳体强旋成形的三维弹塑性模型,并解决了多道次旋压模拟过程中涉及到的应力集中过大,变形不均性等问题。基于该数值模型,对旋压工艺进行了优化,并分析了不同道次下旋压件变形区的应力应变状态。模拟结果表明:道次的增多会导致应力集中现象发生,同时应变增大,造成旋压件变形不均匀、贴膜性不好,采用道次间退火工艺可减小应力集中与变形不均匀性。通过与旋压试验过程中出现的开裂、起皱等缺陷进行对比,验证了多道次强旋成形有限元模型的准确性。

Considering the characteristics of the actual spinning of Ti_2Al Nb alloy,a three-dimensional elastic-plastic FE(finite element)model of power spinning of thin-walled Ti_2Al Nb alloy shell was established based on the dynamic,explicit module of FE software.Stress concentration and the inhomogeneous deformation during simulation were dealt with reasonably.The process parameters were optimized and the distribution of stress and strain of workpiece with different passes were analyzed based on this model.Results show that stress concentration is found with increase of passes,meanwhile strain increases.It will lead to the inhomogeneous deformation of workpiece.To solve this problem,stress-relief annealing between pass and pass were adopted.The reliability of model was validated by comparing the results of simulation and actual production.