Dynamic Behaviour Adaptation of Lightweight Structures by Compressible Constrained Layer Damping with Embedded Polymeric Foams and Nonwovens.

Featured Application: Mitigating vibrations of flat, large-scale structures, for example, car front wall or ceiling, as well as structural and/or cover parts for rail vehicles or noise barriers of different kinds. Furthermore adaptable compact dampers, for example, machine feet are also a promising application field for the proposed novel damping approach. Evanescent morphing in combination with an original concept of Compressible Constrained Layer Damping (CCLD) is a novel and promising approach for dynamic behaviour adaptation. The crucial component of the CCLD is a compressible intermediate layer with its thickness and material properties controlled by fluid actuation, enabling the adjustment of the damping and stiffness of the overall system. To estimate the potential of the CCLD, an analytical model was developed which describes the vibration behaviour of the overall structure, taking into account the compression-driven properties of the intermediate layer. The results confirm the principal correctness of the initial theoretical assumptions regarding the adaptive dynamic behaviour of structures with CCLD treatment. A significant vibration mitigation as well as a high adaptability of dynamic behaviour were observed, however, they show a complex dependence on the system configuration. Nevertheless, the developed analytical modelling approach can already be used for a preliminary system design. Besides the analysed polymer-based foams as the intermediate layer, nonwovens also exhibit compression-dependent shear properties and can therefore be used in CCLD. First preliminary investigations show that the damping performance is on average about ten times better than that of the polymeric foams. [ABSTRACT FROM AUTHOR]