通过对激光喷丸成形(LPF)中残余应力场分布的研究,找出单点喷丸残余应力分布形式,以及单点多次、多点不同路径喷丸中后续冲击对前次冲击残余应力分布的影响规律。对准确控制残余应力分布,获得激光喷丸后所需的板料形状具有指导意义。利用钕玻璃高功率脉冲激光对厚度为1.2 mm的LY12CZ硬铝合金进行了单点激光喷丸,用X衍射应力测定仪考察了单点冲击后材料表面及深度方向的残余应力,用厚度为2 mm 的6061-T6铝合金板料进行三列窄条激光喷丸变形实验。以ANSYS/LS-DYNA有限元分析软件为平台,建立了具有一定精度的激光喷丸过程中冲击波压力的加载模型,对板料的变形过程进行了数值模拟, 分别考察了不同激光能量,板料尺寸,冲击路径等工艺参数对残余应力场分布的影响。实验结合数值模拟探索激光喷丸的主要参数和残余应力场之间的相互关系。

The value and distributing form of the residual stress in laser peening forming (LPF) decide the final sheet contour and deformation shape. To accurately control the distributing of the residual stress and shape the sheet in desiration, it was significant to invest the distributing form among single peen, multiply peen in the same spot and different spots. The experiment of 2mm thick AL6061-T6 and LY12CZ sheet with thickness of 1.2mm was carried out with Nd:Glass high power pulsed laser. The residual stress of peened target was measured by the X-350A stress analytical facilities. The influence of process parameters, such as laser energy, sheet size, peenning path to the residual stress distributing was investigated deeply. The mathematical modeling of shock wave load based on laser peening was established, and a finite-element analysis method based on the ANSYS/LS-DYNA software is applied to simulate the sheet deformation process.