Vibration damping in lightweight constructions by particle-filled cavities
7th CellMAT 2022
U. Jehring1*, P. Quadbeck1, O. Andersen1, T. Weißgärber 1

1 Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden
*Ulrike.jehring@ifam-dd.fraunhofer.de


In mechanical engineering, lightweight materials with high stiffness are used to reduce weight and operating power. However, vibrations pose a problem for lightweight components since the same energy input results in higher vibrational amplitudes compared to heavier components. High amplitudes reduce the precision of machining, limit the cycle rates, shorten the service lifetime, and increase noise emission. Active and semi-active damping systems can mitigate these problems, but usually require additional mass and power input to achieve damping, thereby contradicting the objectives of lightweight construction. Passive vibration damping with materials such as rubber or aluminium foam requires deformations of the material to activate the physical damping mechanisms (sliding of carbon chains or microplastic deformation). However, deformations are often prevented by the high rigidity of the construction. In contrast, damping with particle-filled cavities only requires rigid movement to activate the damping mechanism. The use of small cavities partially filled with mobile particles achieves up to 100 times stronger damping than magnesium, cast iron and aluminium foams while the total density of the particle-filled cavities can approach 1 g/cm³. In the first part of the presentation, the cause of the high damping capacity is traced back from the macroscopic measurement of the component damping to the microscopic level of the damping particles. Depending on the ratio of the external forces to the adhesive forces between the particles, different particle motions result from vibrational excitation. These motions are explained by a model to arrive at conclusions for real applications. In the second part of the presentation, applications of particle damping in a milling slide and vice, wind turbine generator and handheld chain saw are discussed. Furthermore, the “Hoverlight” material, which effectively combines the different damping mechanisms of aluminium foam and particle-filled hollow spheres, is introduced.