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Identification of Radiation Damping Using a Coupled FE/BE Formulation and a Nonlinear Eigenvalue Solver
Author(s) -
Baydoun Suhaib Koji,
Marburg Steffen
Publication year - 2019
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201900319
Subject(s) - radiation damping , eigenvalues and eigenvectors , nonlinear system , acoustic radiation , modal , structural acoustics , solver , vibration , thermoelastic damping , boundary value problem , finite element method , radiation , structural system , boundary element method , acoustics , physics , structural engineering , mathematical analysis , engineering , mathematics , materials science , optics , mathematical optimization , quantum mechanics , particle physics , thermal , meteorology , polymer chemistry
While acoustic radiation damping is a rather small and insignificant aspect of many engineering applications, it is the primary energy‐dissipating mechanism for lightweight structures with large radiating surfaces. Attempts to reduce the vibrational response of those lightweight structures by additional mechanical damping can only be successful if the extent of mechanical damping is comparable or larger than the extent of radiation damping. In this regard, engineers are in need of reliable and flexible methods for the quantification of radiation damping, as well as for the modeling of its effect in an early stage of the design process. In this paper, the modal radiation loss factors are obtained from an eigenvalue analysis of the coupled structural acoustic system. The equations of linear elasticity and acoustics are addressed by finite and boundary element methods respectively. The nonlinear eigenvalue problem is solved by contour integration. The thereby obtained modes represent the structural modes subject to acoustic loading. The modal radiation damping values can be obtained from the complex eigenvalues. The approach is verified based on the example of a honeycomb sandwich panel in air.