Simulation-based Design of Calm Hybrid Particle Dampers with Application to Flexible Multibody Systems

颗粒阻尼器是一种简单设计的被动阻尼器。颗粒颗粒嵌入到连接到振动结构的容器中或嵌入在振动结构中的孔中。由于结构的振动，动量传递给颗粒材料，能量由于颗粒间的碰撞和摩擦作用而耗散。在过去的几十年里，人们对颗粒阻尼器的兴趣与日俱增。即使在已经存在的硬件中，粒子减振也很容易应用，而且已经表明，它至少可以与其他减振技术一样有效。这种消散能量的有效性并不局限于单一频率，而是存在于更宽的频率范围内，这在传统的减振解决方案中并不常见。此外，颗粒阻尼器对各种形式和尺寸以及多种颗粒类型和材料都具有很强的适应性。第一阶段进行的数值和实验分析表明，大部分动能耗散是由碰撞引起的。因此，恢复系数(COR)应尽可能小，以耗散最大能量。为了允许将大量动能从振动结构转移到颗粒上，重金属颗粒(如钢、黄铜甚至钨)是有利的。有限元模拟表明，对于这些材料，颗粒间碰撞的COR相对较高，这对动能耗散提供了限制。使用金属颗粒的颗粒阻尼器的另一个主要缺点是由于撞击而产生相当大的噪音。聚合物颗粒阻尼器的减振效果比较重的金属颗粒小得多，首次尝试使用聚合物颗粒阻尼器。研究目标是进一步发展一种新的基于仿真的分布式颗粒阻尼器用于轻质结构和机械的被动减振设计方法。因此，本项目旨在开发一种全新的混合型颗粒阻尼器。因此，通过使用两种不同类型的材料在一定程度上解耦单个触点的质量和恢复系数，引入了额外的设计自由度。因此，在动态加载过程中，应将重金属材料与具有高阻尼性的粘弹性材料配对。通过这种方法，应该发展一种全新的设计理念来获得小颗粒阻尼器，这种阻尼器比同等质量的优化均匀颗粒阻尼器耗散的能量要大得多。作为一个副作用，预计这些混合粒子阻尼器比经典粒子阻尼器要平静得多。

Particle dampers are simply designed passive damping elements. Granular particles are embedded in a container attached to a vibrating structure or within holes embedded in the vibrating structure. Due to the structural vibrations momentum is transferred to the granular material and energy is dissipated due to inter-particle impacts and frictional effects. In the last decades there has been an increased interest in particle dampers. Particle damping is easy to apply even in already existing hardware and it has been shown that it can be at least as effective as other damping techniques. This effectiveness in dissipating energy is not restricted to a single frequency but exists over a broader frequency range which is not usual in conventional damping solutions. Moreover, particle dampers are highly adaptive with various forms and sizes and a variety of particle types and materials.Numerical and experimental analysis performed in the first project phase has shown that the vast portion of kinetic energy dissipation is due to impacts. Thus, the coefficient of restitution (COR) should be as small as possible to dissipate maximal energy. In order to allow the transfer of significant kinetic energy from the vibrating structure onto the particles, heavy metallic particles such as steel, brass or even tungsten are advantageous. For these materials FE simulation show that the COR is relatively high for inter-particle impacts, providing a limitation on the kinetic energy dissipation. Another major drawback of particle dampers using metallic particles is the generation of considerable noise due to impacts. There have been first attempts using particle dampers made of polymer particles, however due to their much lower particle weight their damping effect is smaller than using heavier metallic particles.The research objective is the further development of a new simulation-based design methodology for passive vibration damping of lightweight structures and machines using distributed particle dampers. Hereby this project aims to develop a completely new type of hybrid particle dampers. Thereby, additional design degrees of freedom are introduced by using two different types of materials to decouple in some extend the mass and the coefficient of restitution of the individual contacts. Hereby, a heavy metallic material should be paired with a viscoelastic material with high damping capability during dynamic loading. With this approach, a completely new design philosophy should be developed to obtain small particle dampers, which dissipate significant more energy than optimized homogenous particle dampers of comparable mass. As a side-effect it is also expected, that these hybrid particle dampers are significantly calmer than the classical particle dampers.