水射流喷丸强化残余应力场的有限元模拟

Finite Element Simulation of Residual Stress Field with Water Jet Peening Strengthening

针对水射流的高湍动特性与受喷靶体材料复杂的弹塑性形变行为,提供一种水射流喷丸强化残余应力场的有限元分析方法。基于准静态压力分布和非线性轴对称面分布载荷,采用多线性各向同性强化的Mises率不相关弹塑性模型,应用Prandtl-Reuss塑性增量理论及增量初应力法,利用线性斜坡载荷加载制度,运用ANSYS有限元软件模拟不同压力作用下水射流喷丸在2A11铝合金材料表层产生的残余应力场,获得残余应力场的分布规律及残余应力沿层深和径向的变化规律,指出残余应力沿层深分为残余压应力区和残余拉应力区,沿径向分为第Ⅰ残余压应力区、残余拉应力区和第Ⅱ残余压应力区,得到表面残余压应力、表层最大残余压应力、残余压应力层深度随着喷丸压力的增加而增大。为验证有限元模拟的正确性,对喷丸表面残余压应力进行试验验证,结果表明,有限元法计算的表面残余压应力值与试验数据近似吻合。

In view of the high turbulence behavior of water jet and the complex elasticity plastic deformation behavior of peened target material,this paper provides an analysis method of finite element for water jet peening strengthening residual stress field.Base on the quasi-static pressure distribution and non-linear axis symmetrical surface-distribution load,an elastic-plastic model with non-relevant Mises rate of multilinear isotropic hardening,Prandtl-Reuss plastic incremental theory and incremental initial stress method,and linear slope load loading system are adopted,and the finite element software ANSYS is used to simulate the residual stress fields produced on the surface layer of 2A11 aluminum alloy material by water jet peening under different pressures,thereby the distribution law of residual stress field and the variation law of residual stress along layer depth and radial direction are revealed.It is pointed out that the residual stress along layer depth is divided into residual pressure stress area and residual tensile stress area,and the residual stress along radial direction is divided into the first residual pressure stress area,residual tensile stress area and the second residual pressure stress area.It is found that the surface residual pressure stress,the biggest residual pressure stress on the surface layer and the depth of residual pressure stress layer augment with the increase of peening pressure.In order to verify the correctness of the finite element simulation,the residual pressure stress on peening surface is tested.The results show that the surface residual stress value calculated by finite element method is proximate to the test data.