A Digital Filter Method for Forced Response Computation

Document type: Conference Papers
Peer reviewed: Yes
Author(s): Anders Brandt
Title: A Digital Filter Method for Forced Response Computation
Conference name: XXI International Modal Analysis Conference
Year: 2003
Publisher: SEM Pub.
City: Orlando
Organization: Blekinge Institute of Technology
Department: Department of Telecommunications and Signal Processing (Institutionen för telekommunikation och signalbehandling)
Department of Telecommunications and Signal Processing S-372 25 Ronneby
+46 455 38 50 00
Authors e-mail: anders.brandt@bth.se
Language: English
Abstract: Transient forced response of mechanical structures is usually computed using time domain integration. This is often computationally costly, and the numerical precision and stability are concerns. In the present paper, a novel method based on modal superposition, using a new digital filter implementation, is presented. Poles and residues of the model are used as input data, which allows for using data from a finite element model, a lumped parameter model, or from experimental modal analysis. Modal damping can be used if the damping matrix is unknown. With the proposed method, the frequency dependant error can easily be computed, and can be chosen arbitrarily small by selecting proper sampling frequency (time increment). The method is applicable to all linear structures and can be used for stationary or transient input data. Simulation results show that the new method is superior to the alternative methods, at less computational cost.
Subject: Mechanical Engineering\Structural Dynamics
Signal Processing\Filter Design
Mechanical Engineering\Structural Mechanics
Keywords: Forced response, digital filter, ramp invariant