薄壁回转体零件铣削加工再生颤振机理与支撑-工艺协同抑振方法

Thin-walled rotary parts, such as casings of aero-engine and nozzles of liquid-rocket, are widely used in aerospace industries. Due to the low-stiffness and small-damping of workpiece, it is prone to arouse regenerative chatter during milling process, which deteriorates the cutting surfaces and restricts the machining productivity. The difficulty of chatter suppression for thin-walled rotary parts mainly attributes to the low mechanical impedance and the small cutting parameters. Therefore, this project aims to achieve chatter avoidance through deep investigation on the dynamic modeling, response analysis, fixture adjustment and process optimization of the milling processes. To be specific, the project plans to (1) discover the mechanism of multi-regenerative milling chatter for thin-walled rotary parts under the influences of additional damping and fixture; (2) set up the time-varying dynamic model for the fixture-workpiece-cutter-tool machining system; (3) propose new response analysis methods considering the feedback of deflection and vibration; (4) present cooperative chatter suppression schemes via fixture adjustment and process optimization under the constraints of milling stability, surface location accuracy and surface roughness; and (5) develop co-optimization software/toolbox and construct experimental platform. The outcomes of this project is believed to have reference value to the high-efficiency chatter-free milling of thin-walled rotary parts.

薄壁回转体零件（如航空发动机机匣、液体燃料火箭喷管等）在航空、航天等领域应用广泛，由于其刚性弱、阻尼小，在外型面铣削过程中极易发生再生颤振，严重影响零件的加工精度和加工效率。本项目围绕薄壁回转体零件铣削加工的颤振抑制难题，针对其低机械阻抗结构特性和小切削用量工艺特点，研究外加阻尼和辅助支撑作用下的工艺系统动力学建模、动态响应分析、支撑装置调控与工艺参数优化，揭示薄壁回转体零件铣削加工的多重再生颤振发生机理，建立“支撑-工件-刀具-机床”工艺系统时变动力学模型，提出考虑加工变形与切削振动反馈的动态响应分析方法，探究无颤振约束、表面位置误差约束、表面粗糙度约束等多源约束下的“支撑-工艺”协同颤振抑制策略，开发协同优化软件包/工具箱并搭建实验验证平台，实现典型薄壁回转体零件的铣削颤振避免，为此类零件的高效稳定切削提供理论和技术支持。

本项目围绕航空发动机机匣等典型薄壁回转体零件铣削过程中的多重再生颤振预测与抑制难题，从动力学建模、动态响应分析、振动抑制策略等方面开展了系列研究工作，具体成果如下：探明了薄壁件铣削加工的多重再生颤振发生机制，建立了考虑瞬时振动反馈的状态依赖型时滞微分方程动力学模型，实现了切削过程刀齿跳离、多重再生等非线性现象的准确刻画；依据时间历程积分和不动点定理，分别提出了两种工艺系统动态响应分析方法，实现了弱刚性工况颤振稳定性、表面位置误差与表面粗糙度同步预报；发明了航空发动机机匣气动自适应支撑夹具，通过支撑夹具（末端机构、支撑位置、支撑力等）和加工工艺（铣刀齿距、主轴转速、轴向切深等）协同优化实现了薄壁回转体零件的铣削稳定性提升和颤振有效抑制，并在某型号航空发动机前机匣典型件上完成了实验验证。项目研究成果共计发表学术论文6篇（SCI检索5篇），授权国内发明专利3项，申请并公开国际发明专利1项；项目实施期间，培养/协助培养博士研究生2人（毕业1人）、硕士研究生3人（毕业1人）。