Vibration reduction by energy transfer using shape adaption

轻量化设计是工程设计中最重要的问题之一。其目的是减轻结构部件的质量，以节省制造和运营过程中的成本、能源和资源。然而，结构越轻，就越容易产生不必要的振动。应尽量减少这种振动，以防止环境、产品和人类受到伤害，并最大限度地延长产品的寿命。减振可以通过被动、半主动或主动措施来实现，其中被动措施意味着不需要外部能量，而半主动措施和主动措施分别利用外部能量来控制耗散或直接抵消振动运动。由于积极措施通常不依赖于消散，它们不属于征求建议书的范围，也不会在本项目中考虑。在被动和半主动措施领域，可以使用两种常用的方法来降低结构的振动，一种是阻尼法，它是将动能耗散到另一种形式的能量；另一种是吸收，它是将动能从临界模式转移到非临界模式。通过采用截面形状自适应来动态调整细长梁状结构的刚度，动能将从关键的低频弯曲模式转移到专门设计的高频吸振器模式，然后以最佳方式进行减振。形状适配机构和吸振器模式的优化设计将使用柔顺机构进行。将通过专门设计的摩擦阻尼器来优化耗散。

Lightweight design is one of the most important issues in engineering design. The objective is to reduce the mass of structural components for the purpose of saving costs, energy and resources in manufacturing and operation processes. However, the lighter the structure is, the more it is prone to unwanted vibrations. Such vibrations should be minimized in order to prevent the environment, products and human beings from being harmed and to maximize the lifetime of the products.Vibration reduction can be achieved by passive, semi-active or active measures, where passive means that no external energy is needed, while semi-active and active measures employ external energy to either control dissipation or directly counteract the vibrational motion, respectively. Since active measures usually do not rely on dissipation, they do not fall in the scope of the call for proposals and will not regarded in this project. In the realm of passive and semi-active measures, two general approaches can be used to reduce vibration in structures, namely that of damping, which is the dissipation of kinetic energy into another form of energy, or that of absorption, which is the transfer of kinetic energy from a critical mode into an uncritical mode.The envisioned approach will combine the concepts of damping and absorption in a novel way by integrating the functionality of a damped, tuned mass absorber into a shape adaptive structure. By dynamically adapting the stiffness of a slender, beam-like structure using shape adaption of the cross-section, kinetic energy will be transferred from the critical low-frequency bending modes into a specifically designed, higher frequency absorber mode, which can then be damped in an optimal way. Optimal design of the shape adaption mechanism and of the absorber mode will be pursued using compliant mechanisms. The dissipation will be optimized by a specifically designed friction damper.