含多重非光滑力学因素机械系统的动力学特性和实验研究

Dynamic characteristics of mechanical systems with multiple non-smooth mechanical factors is studied with emphasis on the multi-parameter and multi-performance co-simulation analysis for acquiring reasonable parameter matching range of collaborative optimization between dynamical characteristics and function objectives. The fundamental group of impact motions of vibrating system with symmetric bilateral stops and unilateral stop is considered which have the excitation period and differ by the number of impacts. Codimension-two bifurcations of impact motions with fundamental period are analyzed to reveal the generation mechanism of subharmonic impact motions in the transitional region between adjacent fundamental impact motions, and the influences of constraint conditions and parameters on pattern types, essential characteristic and distribution regularities of the subharmonic impact motions are further studied. Dynamics of frictional vibration system with clearances or constraints are studied, including emerging behavior of stick-slip effect of impact motions with fundamental period, the correlation of chatter-impact sticking and slip sticking, the interaction and competition of different sticking modes, etc. Finally, the influences of these dynamic factors induced by friction and chatter on types and features of transitional regions of adjacent impact motions with fundamental period are ascertained. The electronic circuits are designed for physical implementation of dynamics of mechanical systems with multiple non-smooth mechanical factors, and the experimental results will provide some pattern types and relevant parameters of complicated dynamic behaviors for multi parameter simulation analysis of the systems. The rail wheelset impact vibration, caused by hunting motion of heavy-load and speed-raising freight car, is studied with emphasis on its bifurcation characteristics. The influences of key dynamic parameters on critical speed of hunting instability of the freight car are analyzed, and parameter sensitivity and reasonable parameter matching range are determined by multi parameter and multi-performance co-simulation analysis.

项目研究含多重非光滑力学因素机械系统的动力学特性，通过多参数多性能仿真分析确定系统动态特性和功能目标协同优化的参数匹配规律及合理匹配范围。基于含对称刚性约束副和单侧刚性约束振动系统的基本周期冲击振动群的余维二分岔，研究相邻基本周期冲击振动非迟滞型转迁域内亚谐冲击振动的形成机理，揭示约束条件和参数对亚谐冲击振动群模式、特征及其在转迁域分布规律的影响。研究带有间隙的摩擦振动系统粘滑型基本周期冲击振动粘滞过程的涌现行为、颤冲击粘滞和滑移粘滞的相关性、不同模式粘滞的交互作用和竞争规律及其对相邻基本周期冲击振动转迁域类型和特征的影响。设计实施含多重非光滑力学因素的机械系统的等效动态特性的电子电路，为系统的多参数仿真分析中复杂动力学行为的辨识提供可能的模式类型及参数信息。研究重载提速货车蛇行运动中的轮轨冲击振动及分岔特性，揭示关键动力学参数对货车蛇行失稳临界速度的影响, 确定参数敏感度及合理匹配范围。

项目研究了含多重非光滑力学因素的机械系统的动力学特性，通过多参数、多性能仿真分析确定了系统动态特性和功能目标协同优化的参数匹配规律及合理匹配范围。基于含对称刚性约束副和单侧刚性约束的振动系统的基本周期冲击振动群的余维二Grazing分岔(Double-grazing，Flip–grazing和Fold–grazing分岔)、二重鞍结分岔和Flip–鞍结分岔，研究了低频域内相邻基本周期冲击振动非迟滞型转迁域内亚谐冲击振动的形成机理，揭示了约束条件和约束参数对亚谐冲击振动群的模式类型、本质特征及其在转迁域内分布规律的影响。研究了带有约束和间隙的摩擦振动系统粘滑型基本周期冲击振动粘滞过程的涌现行为，揭示了颤冲击粘滞和滑移粘滞的相关性、不同模式粘滞的交互作用和竞争规律及其对相邻基本周期冲击振动转迁域类型和特征的影响。设计实施了含多重非光滑力学因素的机械系统的等效动态特性的电子电路，通过电路的输出信号观测了系统低频域内基本周期冲击振动群的模式类型、群内亚谐冲击振动的模式类型及规律特征。基于轮缘力及钢轨对轮对的分段线性约束假设，研究了铁道车辆在平直和大半径曲线轨道蛇行运动中轮轨冲击振动及分岔特性，揭示了悬挂参数、车轮踏面等效锥度和摩擦系数对车辆蛇行失稳临界速度、轮轨冲击的模式类型和多样性特征的影响, 确定参数敏感度及参数合理匹配范围。