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

粒子阻尼器是一种设计简单的被动阻尼元件。颗粒颗粒嵌入附在振动结构上的容器内或嵌入在所述振动结构中的孔内。由于结构振动，动量被传递到颗粒材料中，能量由于颗粒间的碰撞和摩擦效应而耗散。在过去的几十年里，人们对粒子阻尼器越来越感兴趣。粒子阻尼即使在已经存在的硬件中也很容易应用，并且已经证明它至少可以与其他阻尼技术一样有效。这种耗散能量的有效性并不局限于单一频率，而是存在于更广泛的频率范围内，这在传统的阻尼解决方案中并不常见。此外，颗粒阻尼器对各种形状和尺寸以及各种颗粒类型和材料具有很强的适应性。在工程第一阶段进行的数值和实验分析表明，很大一部分动能耗散是由于撞击造成的。因此，恢复系数（COR）应尽可能小，以耗散最大的能量。为了将振动结构的动能转移到粒子上，重金属粒子如钢、黄铜甚至钨是有利的。对这些材料的有限元模拟表明，质点间碰撞的COR相对较高，对动能耗散有一定的限制。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产生相当大的噪音。人们曾首次尝试使用由聚合物颗粒制成的颗粒阻尼器，但由于它们的颗粒重量要低得多，因此其阻尼效果要小于使用较重的金属颗粒。研究目标是进一步发展一种新的基于仿真的设计方法，用于使用分布式粒子阻尼器的轻型结构和机器的被动振动阻尼。因此，本项目旨在开发一种全新的混合粒子阻尼器。因此，通过使用两种不同类型的材料来在一定程度上解耦单个接触的质量和恢复系数，引入了额外的设计自由度。因此，在动加载过程中，重金属材料应与具有高阻尼能力的粘弹性材料配对。利用这种方法，应该开发一种全新的设计理念来获得小颗粒阻尼器，它比优化的同等质量的均匀颗粒阻尼器耗散更多的能量。作为一个副作用，我们也期望这些混合粒子阻尼器比经典粒子阻尼器更平静。

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.