参数时空骤变及热振动耦合五轴机床非线性动态可靠性设计研究

针对国产五轴机床低动态加工精度、低保持性及其低可靠性问题，(1)研究柔性工件支撑系统空间不同点刚度和阻尼的非线性解析演化模型及其非线性振动，揭示动力学参数空间骤变演化规律并提出动态性能及保持性提升方案；(2)探究刀具进给系统热振动耦合的时间上骤变的非线性刚度和阻尼演变模型并探索其非线性动力学分析，阐明热振动耦合演变规律并提出动态性能及保持性提升措施；(3)构建考虑刀具磨损、加工生热与冷却的时滞动态切削力模型，提出五轴机床参数时空骤变及热振动耦合的多自由度时滞非线性颤振模型并探索其求解方法，获得低动态加工精度及保持性的关键因素；(4)确定随机参数及其演化的随机过程分布，创建多相关随机过程和随机变量共存的非线性动态可靠性分析及其多目标和多约束的可靠性优化设计理论和方法，给出五轴机床最优可靠性设计方案，为解决国产五轴机床动态加工精度、保持性及其可靠性较低问题提供基础理论与方法。

Aiming at the problems of low dynamic machining accuracy and its retainability and their low reliability of domestic five-axis machine tools, (1) the nonlinear analytical evolution model of stiffness and damping at different points in the space for the flexible workpiece system and its nonlinear vibration analysis are studied to reveal the evolution law of the sudden change dynamic parameters in the space, and propose a dynamic performance and retainability improvement scheme, (2) the time-dependent, thermal-vibration coupling, and nonlinear stiffness and damping evolution model for the tool feed system and its nonlinear dynamics analysis are discussed to clarify the thermal-vibration coupling evolution law, and to propose dynamic performance and retainability improvement solution, (3) the time-delay dynamic cutting force model considering tool wear, machining heat generation and cooling is explored, and the thermal-vibration coupling, multi-degree-of-freedom, time-delay, and nonlinear flutter model for the five-axis machine tool with the time-space sudden change dynamics parameters is constructed and resolved to obtain key factors resulting in the low dynamic machining accuracy and its retainability, (4) the random parameters and their evolutionary stochastic process distributions are determined, and the correlated stochastic processes and random variables coexisting, and the nonlinear dynamic reliability analysis and its multi-objective and multi-constrained optimization design theory and method are researched, to give the optimal five-axis machine tool reliability design. This project provides fundamental theory and method for solving the problems of the low dynamic machining accuracy and its retainability and their low reliability of domestic five-axis machine tools.