Estimation of Modal Dampings for Unmeasured Modes

Ferenc Pápai, Sondipon Adhikari, Bor-Tsuen Wang
2012 Slovak Journal of Civil Engineering  
Damping effects are of great interest for structural analysis and evaluations. Structural modal damping characteristics can be obtained from experiments. This paper introduces new possibilities for the modelling of the damping of a dynamic system with classical normal modes and provides an overview of the known methods for formulating a damping matrix base with experimental modal damping values. The proposed method offers an opportunity to extrapolate modal damping values for unmeasured modes
more » ... unmeasured modes by a regression method based on the measured modal properties. The points of view on the choice of an analytical form for damping regression functions are examined. An analytical form of regression functions can be chosen as the modal decay rate versus the square of the frequency or the modal damping ratio versus the frequency. Damping regressions can be performed based on a group of typical vibration modes, such as bending, torsion and lateral, symmetrical or anti-symmetrical modes. The regression data obtained for the damping constants can then be applied in a finite element model for further structural analysis.
doi:10.2478/v10189-012-0018-3 fatcat:yzzqaairffh7reryvh4rclehum