Calming Vibrational Systems by Optimized Placement of Novel Situation-Aware Frictional Damper Elements

过去几年，化石能源运输船成本的不断上升和法律法规的收紧，要求所有类型的机械都要有高能效。因此，为了提高效率，系统地减少了摩擦和其他减振影响的影响。另一方面，轻量化设计的强烈趋势使机械结构对振动激励更加敏感。因此，有必要在不影响期望的操作和降低整个机构的效率的情况下，有效地、紧密地使振动平静下来。因此，开发新型和创新的减振装置(DD)是不可避免的，以保护机器免受不必要的振动。通常被忽视的阻尼力的非线性可能为设计与情况相关的行为提供特别巨大的潜力，而不需要实施控制器或提供额外的能量。特别是具有粘滑转变的干摩擦力，使得设计能够改变其行为的元件成为DDS适应当前情况的基本部件。对于1-DOF系统，干摩擦阻尼对强迫振动的影响在文献中已被广泛讨论。基于摩擦的DDS主要基于摩擦力的耗散特性，或者利用几乎所有关节中固有的结构性摩擦，或者基于特意设计的具有局部或分布摩擦的机械部件。遗憾的是，对于多自由度系统的影响，特别是摩擦耗散单元的最优布置，以及它们与原结构之间的强非线性相互作用，人们的关注明显较少。该项目的主要目标是研究如何使用新的基于摩擦的DDS来集中减少强迫振动。除了对这些设备的分析之外，还将设计出有效的方法，使其能够以最佳方式配置和放置在机械系统上。为了实现这一总体目标，将比较基于四个基本要素(顺序摩擦弹簧、调制法向载荷、顺序间隙摩擦和分布摩擦)的适当组合的各种DDS提供节能和情景感知行为的能力。将开发分析方法，以便以可靠的方式评估这些设备在振荡系统中的效率。利用分析和数值优化技术，将考虑到这些强非线性元素之间的相互作用，研究在基本结构内合理放置DDS的问题。最有希望的设备将进行原型制作和实验测试。

Continuously increasing costs of fossil energy carriers and tightening legal regulations in the last years require high energy efficiency in all types of machinery. Consequently, in order to increase efficiency, the impact of friction and other damping influences is systematically reduced. On the other hand, the strong trend to light weight design makes mechanical structures even more sensitive against vibrational excitation. Thus, it is necessary to calm vibrations effectively and tightly focused without influencing the desired operation and decreasing the efficiency of a mechanism as a whole. Hence, the development of new types and innovative designs of damping devices (DD) is inevitable for protecting machines from undesired vibrations.Usually neglected nonlinearities of damping forces may offer a particularly huge potential to design situation-dependent behavior without the need to implement a controller or supply additional energy. Especially dry friction forces with stick-slip transitions make it possible to design elements that switch their behavior and thus can serve as basic components for DDs adapting themselves to the current situation.For 1-DoF-systems the impact of dry friction damping on forced oscillations has been extensively discussed in the literature. Friction based DDs are mainly based on the dissipative properties of friction forces and either utilize the constructive friction which is inherently present in almost all joints or are based on deliberately designed machine components with localized or distributed friction. Unfortunately significantly less attention has been payed to the effects occurring in systems with many DOF and especially to the optimal placement of the friction based dissipative elements and to the strongly non-linear interactions between them and the original structure. The main objective of the project is to investigate how novel friction-based DDs can be used for the focused reduction of forced vibrations. Beyond the analysis of these devices, also efficient approaches will be devised, enabling to configure and place them on mechanical systems in an optimal way. In order to achieve this overall goal, various DDs based on appropriate combinations of four basic elements (sequential friction-spring, modulated normal load, sequential backlash-friction and distributed friction) will be compared with respect to their ability to provide energy-efficient and situation-aware behavior. Analytical methods will be developed which allow to evaluate the efficiency of these devices in oscillating systems in a reliable way. Using both analytical and numerical optimization techniques, the aspect of a sensible placing of the DDs within the basic structure will be investigated, taking interactions between these strongly non-linear elements into account. The most promising devices will be prototyped and tested experimentally.