飞机机加框激光喷丸轨迹生成及数值分析

Trajectory generation and numerical simulation of machined frame by laser shock peening for aircraft

在飞机服役过程中,部分金属零件因承载应力及环境因素,疲劳及腐蚀问题突出,常用表面强化在零件表层引入残余压应力进行改善。激光喷丸强化利用短脉冲激光束作为介质对材料表面改性达到强化效果,文中利用基于CATIA软件开发的激光喷丸强化工艺轨迹规划平台,实现喷丸区域CAD几何特征提取与喷丸轨迹的规划、生成、可视化及输出功能的一体化,对某机型货舱门框的机加框零件进行激光喷丸强化轨迹路径的规划和输出。利用ABAQUS软件子程序分析机加框激光喷丸强化后的变形行为,包括喷丸区应力、应变及变形位移量分布特点。结果表明:在给定工艺参数情况下,机加框喷丸区最大压应力位于表面1.0 mm左右,最大等效应变0.03~0.04,喷丸区域表面平均变形位移50μm,数值模拟验证了轨迹平台用于规划生成轨迹的适用性。

The fatigue and corrosion problems of some metallic parts will often occur due to alternating load and severe environment condition during aircraft’s service period.The surface treatment process was always utilized to improve fatigue and wear crack propagation resistance performance by inducing compressive stress through thickness direction.Laser shock peening(LSP)is an effective laser-based surface processing technique to enhance surface strength and extend fatigue life of metallic part.In this paper,the trajectory planning and generation platform was developed and integrated into CATIA software.The platform could achieve the functions by integrating trajectory planning,generation,visualization and results output with extraction of CAD geometric features in peening zone.And then the platform was used to generate peening path of machined frame for aircraft cargo door bulkhead.The deformation behavior of machined frame was studied in terms of stress,strain and deformed displacement after LSP by ABAQUS subroutine analysis.The results show that maximum compressive stress locates 1.0 mm below the surface and with equivalent strain of 0.03~0.04 at the same location by giving LSP process parameters in this paper.The average deformed displacement is about 50μm in typical peening region.Besides,the finite element analysis of LSP for machined frame also validates the suitability of trajectory planning and generation in the aforementioned integration platform.