磨料水射流冲击材料壁面的模拟与试验

Simulation and experiment of impinged material surface with abrasive water jet

为了在小尺度范围内揭示磨料水射流的作用机理,对工作压力为250 MPa时磨料射流在靶距为3.0 mm处的断面上的射流中心、射流外缘以及两者平均速度进行计算.利用有限元软件对不同厚度的钢板在上述3个速度下进行冲击计算.结果表明:边缘处由于磨料速度较小,对钢板的冲击产生较小的形变,钢板表面出现微小的破坏,磨料被反弹;磨料速度在平均速度附近时对钢板的冲击使钢板出现较大的形变,且表面的破坏较明显,此时磨料颗粒嵌入到钢板内;在射流中心处由于磨料的速度较高,直接将钢板穿透,钢板的形变量比边缘处磨料作用时的更小.在相同条件下进行试验,利用光学轮廓仪对实际切割断面的粗糙度进行显示以验证模拟结果,模拟结果与试验结果基本吻合.

To investigate the mechanism of abrasive water jet cutting process with micro scale characteristics,the abrasive speeds at jet stream center,jet edge and average abrasive speed at the section with distance of 3.0 mm from nozzle outlet were calculated under operation jet pressure of 250 MPa.Finite element method was used to simulate the impact of steel plates with different thicknesses.The results show that the abrasive speed is relative small at the jet edge with little deformation on the steel plate,and little damage is appeared on the surface with bounced abrasive.Large deformation is appeared with apparent surface damage when the abrasive speed reaches the average speed,while the abrasives are embeded into the steel plate.Abrasives go through the plate directly at the jet center,and cause less deformation than that with abrasive speed at jet edge.The plate strain gradually decreases with the increase of thickness of steel plate at the same abrasive speed.The experiment was conducted under the same conditions,and the optical profile-scanning device was used to examine the distributions of roughness.The simulation results are in good accordance with the experiment results.