空化水喷丸诱导45钢残余应力场的数值模拟与验证

空化水喷丸工艺是利用淹没式空化射流中微小空泡在材料表面溃灭时产生的冲击波压力,用该压力来诱导金属零部件的表面形成压缩残余应力层,进而提高其疲劳寿命。本文依据空化水喷丸强化45钢的试验,运用ANSYS/LS-DYNA软件建立非线性无弹性模型中的双线性各向同性模型,模拟了空化水喷丸工艺过程中冲击波压力和材料相互作用的动力学过程,以及形成在表层的压缩残余应力场分布规律,讨论了本构关系、网格划分、载荷大小、加载历史等关键问题。采用不同峰值载荷的冲击波压力和多冲击波连续加载的方法,实现了对残余应力场分布的预测。利用微小部残余应力测定装置(PSPC/MICRO)对上述工艺条件诱导残余应力的大小进行测定,数值模拟的结果和X射线衍射法测得的残余应力大小和分布吻合较好。

Experiment and Numerical Simulation of Waterjet Cavitation Peening Processing in 45 Steel

Water-jet cavitation peening was a new technology using impact wave pressure generated by micro bubbles collapsing near the surface of material in the submerged cavitating jets processing, which was used for inducing compressive residual stress layer in the surface of metallic materials, and its fatigue life was improved. According to the cavitating water shot peening tests on 45 steel, a bilinear isotropic model in nonlinear inelastic model was created by ANSYS/LS-DYNA finite element analysis software, the interaction between shock wave pressure and material of dynamics of the cavitating jets processing was simulated, the distribution rule of compress residual stress forming in the surface layer was obtained, and the constitutive relation ship, meshing, load magnitude, load history and other key issues were discussed. The shock wave pressure under different peak loads and the method of continuous wave loading were adopted to predict the distribution of residual stress. A small residual stress measurement device (PSPC/MICRO) is used to test the residual stress induced by WCP. The results show that the numerical simulation agrees well with the experimental results of magnitude and distribution of the residual stress determined by the X-ray diffraction method.