考虑性能退化的机构系统动力学理论与实验研究

Based on the analysis of the existing wear models, this project will expound the differences and relations and application scope of the wear models in theory. The wear law of kinematic pair in mechanism in the real working condition, under larger pressure and speed range, will be explored. The wear failure mechanism of kinematic pair in the environment of SF6 atmosphere is to be revealed. Then, the wear model will be improved and developed through collecting and analyzing the wear failure basic data of kinematic pair. The nonlinear dynamic equation of elastic linkage mechanism, used for performance degradation analysis and considering the coupling effects between wear of kinematic pair as well as working interface and dynamic characteristics, will be established. Meanwhile, an efficient numerical method for solving the nonlinear dynamic equation will be put forward. The design theory and control strategy for a loading analog device combining the advantage of linkage mechanism and electric loading technology, used for performance degradation test of mechanism, will be studied. The experiment for measuring the character quantity of performance degradation of mechanism is to be carried out, and the theory model for performance degradation trajectory will be formulated based on the test data. The relationship between the character quantity of performance degradation and structure as well as working parameters will be analyzed, and a way to increase the performance margin of mechanism will be explored. The design theory and method to guarantee the mechanism's reliability in whole lifespan will be put forward, as well as be used in the design of operating mechanism of giant circuit breaker. This study will raise the theoretical level as well as the ability of solving real engineering problems for mechanism dynamics.

对现有的磨损模型进行分析归纳，从理论上阐明其区别与联系以及应用范围。探索在真实工作状况下，较大的压强和运动速度范围内，机构运动副的磨损规律。揭示在SF6气氛环境下机构运动副磨损失效的机理。获取机构运动副磨损的基础数据，完善和发展磨损模型。建立考虑运动副和工作界面磨损与机构动力特性相互耦合影响，可对弹性机构系统性能退化规律进行模拟分析的非线性动力学方程，给出有效的数值求解方法。探索将连杆机构与电动加载有机集成，用于机构性能退化试验的模拟加载装置的设计理论与控制技术。对机构系统性能退化特征量进行测试，基于试验数据建立其性能退化轨迹模型。分析机构系统性能退化特征量与结构和工况参数之间的关系，给出提高机构系统性能裕度的途径。形成保证机构系统整个服役周期内性能可靠的设计理论方法，将其应用于巨型高压断路器操动机构系统设计。提高机构系统动力学研究的理论水平和解决实际问题的能力。

机构是各种机械装置的主体部分，经过长期运转机构系统的运动副不可避免地会产生磨损，导致机构系统的性能退化。考虑性能退化的机构系统动力学理论与实验研究有重要意义。对近年来国内外机构动力学中关节效应的研究进行了详细分析，分析归纳了磨损模型、接触力模型、间隙运动学模型及其在多体动力学中的建模过程。发明并研制出了特殊气体氛围下的运动副摩擦磨损实验装置，分别在大气氛围和模拟SF6气氛的惰性气体氛围条件下，对不同压强和运动速度范围内的机构运动副的摩擦磨损规律进行了试验研究，为考虑性能退化的机构动力学研究提供了数据。以少自由度并联机构、空间4杆机构、平面4杆和5杆机构、高压断路器传动机构为对象，建立了考虑运动副间隙、摩擦、磨损效应，可对其性能退化规律进行研究的机构系统动力学模型，给出了相应的求解过程和计算方法。考虑到运动副元素之间接触刚度与机构系统动力学模型之间的耦合性，以非线性刚度系数代替了Flores接触模型中的常数刚度系数而提出了一种改进的接触力模型。发明并研制出了连杆机构模拟加载实验装置,为机构性能退化试验提供了基础。在考虑运动副非规则磨损对断路器传动机构系统性能退化的影响基础上，采用小子样的虚拟增广法和Boot-strap法对基于Archard 模型计算出的该机构运动副的磨损数据进行扩展，根据磨损退化量分布规律分别得到了扩展前后的机构可靠度变化曲线。分析了断路器机构触指工作界面接触压力和滑动摩擦阻力的变化规律，建立了触指径向变形量和接触压力的变化方程，得到了触指的变形量和摩擦力之间的非线性关系。采用相似理论对断路器传动机构的主触头机构进行了相似模型设计，对该机构的运动副反力和连杆的动态应力相似关系的正确性进行了分析验证。对断路器传动机构系统进行了深入的运动学动力学分析，找出了影响其性能退化的薄弱环节，对断路器传动机构进行了优化改进设计，改进后的传动机构经企业实验验证，其无故障运行次数明显提高。