基于镗削残余应力张量预测的凸轮轴支撑体孔面变形研究

Research on Deformation Prediction of Camshaft Support Hole Surface Based on Boring Residual Stress Tensor

  • 摘要: 为了探明ZL702A铝合金的镗削加工残余应力遗传演化规律并减小凸轮轴支撑体零件的应力诱导变形量,本研究开展了多工步镗削试验与加工残余应力测试、孔壁加工残余应力有限元仿真建模与计算、零件孔壁加工残余应力张量加载方法研究,通过贴合钢制厚片的方式限制镗削后零件的二次变形,测得有效的表面残余应力数据;通过多刀切削模型建模与子程序加载的方式实现了残余应力遗传演化的模型间传递,提高了仿真计算效率;基于弹性力学的六向应力状态换算方法对应力张量进行了换算并对零件在不同工艺参数下的加工变形进行了仿真预测. 研究结果表明,加工孔在限制/未限制二次变形的情况下其应力测试结果会有明显差距. 本研究建立的子程序仿真方法的仿真结果与连续切削仿真结果以及试验结果具有较好的一致性,当f=0.1 mm/r、N=100 r/min时零件残余应力诱导变形可以获得最佳的平面度和同轴度误差.

     

    Abstract: To investigate the hereditary evolution of machining-induced residual stress in ZL702A aluminum alloy during boring and to reduce stress-induced deformation in the camshaft support body, in this study multi-step boring experiments and residual stress measurements were carried out. Additionally, finite element simulation modeling and calculations of residual stresses on the bore wall were performed, along with research on loading methods of residual stress in components. By restricting secondary deformation of the bored parts using steel shims, effective surface residual stress data were obtained. The hereditary evolution of residual stresses was modeled and transferred between simulations using a multi-cut model and subroutine loading, improving computational efficiency. Based on the six-directional stress state conversion method in elasticity theory, stresses were converted, and machining deformations of components under different process parameters were predicted. The results indicate significant differences in residual stress measurements between cases where secondary deformation was restricted and unrestricted. The simulation results from the subroutine-based method established in this study show good consistency with both continuous cutting simulations and experimental results. When the feed rate f=0.1 mm/r and the rotational speed N=100 r/min, the residual stress-induced deformation of the component achieves optimal flatness and coaxiality errors.

     

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