Acoustic impedance sensitivity approach for defining absorbing material layout using the wave based method

• Published in: Journal of sound and vibration Vol. 483; p. 115471
• Main Authors: Koo, Kunmo, Pluymers, Bert, Desmet, Wim
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 29.09.2020; Elsevier Science Ltd
• Subjects: Absorbing material layout; Acoustic absorption; Acoustic impedance; Acoustic impedance sensitivity; Acoustic noise; Damping; Design optimization; Finite difference method; Finite element analysis; Finite element method; Layouts; Mathematical models; Noise reduction; Optimization; Polynomials; Sensitivity; Structural members; Thickness; Vibration analysis; Wave based method; Waveform analysis; Acoustic impedance sensitivity; Wave based method; Design optimization; Absorbing material layout
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/j.jsv.2020.115471

This study used the wave based method (WBM) to investigate the optimum layout of an absorbing material on a vibrating surface. The structural dynamic behavior was examined using the finite element model, and the acoustic response was computed using the WBM. The thickness of the absorbing material on each structural element was considered as the design variable. The sensitivity of the acoustic response to the acoustic impedance was derived using wave based system matrices, and a polynomial function was used to describe the impedance variation with respect to the thickness of the absorbing material. Thereafter, the final design sensitivity of a vibro-acoustic model was derived with respect to the thickness of the damping material using the chain rule. The design sensitivity results were found to be in good agreement with the results of the central finite difference methods. The design optimization of the absorbing material layout was applied to a vibrating surface using the design sensitivity results under various excitations, and the results of the optimization showed a layout similar to the active intensity plot of the vibrating surface. The proposed method can easily be applied to reduce the noise produced by a vibrating structure. •Design sensitivity of acoustic impedance was derived using wave based method.•The optimization of absorbent panel layout on a vibrating structure was conducted.•The performance of the optimization was verified through numerical examples.•The noise reduction can be achieved at a lower cost with better performance.