围限颗粒介质差速器自适应传动机理与性能优化

The coupling between particle packing structure and mechanical properties of granular media leads to an amazing flexibility. Ingenious use of the unique yield expansion effect of confined granules medium is expected to form a new adaptive differential transmission principle and guide the technological innovation. Based on the idea of that the stability and yield behavior of confined granular media depending on the mesoscopic clusters and their interactions, the introduction of "confining attraction effect", the establishment of dual stability criterion of fusion power ring and geometry stacking structure to improve numerical simulation methods as well as the development of a comprehensive test device, the research project systematic study the synergistic coupling deformation mechanism and mechanical response of the multi-scale power ring and local preferentially structure during various hard-sphere particles yielding process under different confining strength. Besides, the state equation of local yield and global synergies flow will be built, based on the nonlocal liquidity concept, to obtain the density distribution, the rate of shear deformation, stress field and other characterization parameters. The project aims to determinate the collaborative movement patterns, mechanical properties and its influencing factors of confined granular media in yield expansion under complex shear action, to speed up the exploration of new differential transmission principle and technical way. With optimizing the structure and transmission performance of confined granular media, a new design concept and theoretical guidance can be provided to investigate the low-cost and high-performance full-time self-adapted differential for multi-axle drive vehicles.

颗粒介质因颗粒堆积结构与力学性能之间的奇妙耦合而产生令人惊奇的柔性。精妙地利用围限颗粒介质独特的屈服膨胀效应，有望形成新型自适应差速传动原理并引导技术革新。项目基于介观团簇及其相互作用决定围限颗粒介质稳定性和屈服行为的研究思路，引入"围限相吸效应"，建立融合力环和几何堆积结构的团簇结构双稳定性判据，改进数值模拟方法，并研发综合测试装置，系统研究不同围限强度下多种物性硬球颗粒屈服变形过程中多尺度力环与局部择优堆积结构相互耦合协同变形机理和力学响应；并基于非局域流动性概念，构建局部屈服与全域协同流动状态方程，求解获取密度分布、剪切变形速率和应力场等表征参数。项目旨在探明围限颗粒介质在复杂剪切作用下屈服膨胀时颗粒的协同运动模式、力学特性及其影响因素，探索新型差速传动原理及技术途径，逐步优化结构和传动性能，为研发低成本高性能全时自适应汽车差速器提供新的设计理念和理论指导。

项目针对围限硬球颗粒介质剪切变形行为和力学响应开展实验、理论和数值模拟研究。揭示颗粒介质蕴含“剪切变形与固-液相变耦合、临界转变与粘-滑行为共存”的复杂机理，提出围限硬球颗粒介质具有类流变体特性的观点和表征方法；研发出围限硬球颗粒介质速差感应自适应联轴器的技术原型。.一、开展的主要工作：.（1）围限硬球颗粒介质的循环或持续剪切行为、物性临界演化机理和力学响应；.（2）剪切过程摩擦不连续自激粘-滑行为和影响因素；.（3）汽车性能综合评价指标的建立和应用；.（4）围限硬球颗粒速差感应自适应联轴器结构和性能优化。.二、取得的重要结果：.（1）证实围限颗粒介质剪切膨胀效应的粘-滑特征（附件1） 持续剪切作用下颗粒介质的剪切膨胀效应表现为周期性膨胀-收缩的粘滑行为，并非持续膨胀。.（2）确认颗粒介质堆积密度与颗粒数目和围限边界相关（附件2） 对围限颗粒介质物性和力学行为进行表征不能忽视颗粒数目和围限条件的影响。.（3）提出堆积密度波动触发颗粒介质物性临界转变的观点（附件3） 颗粒介质堆积密度波动时固液相变引起物性改变，提出解释粮仓失效或触发临界转变的新见解。.（4）形成堵塞密度的测量原理和方法（附件4） 堵塞密度综合反映体积分数和弹性模量的协同变化。测量体积分数和弹性模量确定与围限剪切条件相应的堵塞密度。.（5）基于堵塞密度表征颗粒介质“类流变体”临界特性（附件5） 颗粒介质剪切变形过程伴随固液转变和粘滑临界行为，堵塞密度作为表征流变临界特征的状态参数。.（6）构建了汽车综合性能评价指标体系（附件6），面齿轮建模和验证（附件0），完成自适应联轴器技术原型和其他成果（附件7和附件8） .三、研究意义和前景. 基于对颗粒介质“剪切变形与固-液相变耦合、临界转变与粘-滑行为共存”复杂行为的理解和应用，未来三年，有望在围限效应、阻尼特性、摩擦模型、面齿轮研发、自适应传动、扭振行为和稳定性等主题上发表较高水平论文，在速差自适应联轴器、阻尼器研发和应用上取得新进展。