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Advances in Aircraft and Spacecraft Science Volume 3, Number 3, July 2016 , pages 331-349 DOI: https://doi.org/10.12989/aas.2016.3.3.331 |
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Modelling and FEA-simulation of the anisotropic damping of thermoplastic composites |
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Matthias Klaerner, Mario Wuehrl, Lothar Kroll and Steffen Marburg
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| Abstract | ||
| Stiff and light fibre reinforced composites as used in air- and space-craft applications tend to high sound emission. Therefore, the damping properties are essential for the entire structural and acoustic engineering. Viscous damping is an established and reasonably linear model of the dissipation behaviour. Commonly, it is assumed to be isotropic and constant over all modes. For anisotropic materials it depends on the fibre orientation as well as the elastic and thermal material properties. To portray the orthogonal anisotropic behaviour, a model for unidirectional fibre reinforced plastics (frp) has been developed based on the classical laminate theory by ADAMS and BACON starting in 1973. Their approach includes three damping coefficients - for longitudinal damping in fibre direction, damping transversal to the fibres and shear based dissipation. The damping of a laminate is then accumulated layer wise including the anisotropic stiffness. So far, the model has been applied mainly to thermoset matrix materials. In this study, an experimental parameter estimation for different thermoplastic frp with angle ply and cross ply layups was carried out by measuring free vibrations of cantilever beams. The results show potential and limits of the ADAMS/BACON damping criterion. In addition, a possibility of modelling the anisotropic damping is shown. The implementation in standard FEA software is used to study the influence of boundary conditions on the damping properties and numerically estimate the radiated sound power of thin-walled frp parts. | ||
| Key Words | ||
| damping; thermoplastic composites; FEA simulation; anisotropy | ||
| Address | ||
| Matthias Klaerner, Mario Wuehrl and Lothar Kroll :Institute of Lightweight Structures Technische Universität Chemnitz, 09107 Chemnitz, Germany Steffen Marburg : Lehrstuhl für Akustik mobiler Systeme, Technische Universität München, 85748 Garching, Germany | ||
