Decentralised velocity feedback control for thin homogeneous and lightweight sandwich panels

This thesis presents theoretical and experimental studies on decentralised velocity feedback control for thin homogeneous and lightweight sandwich panels. This research is motivated by the increasing interest in lightweight design for fuel efficient transportation vehicles. Lightweight sandwich panels are very appealing due to their high stiffness to weight ratio but also exhibit undesirable sound transmission properties which could cause problems with vehicle interior noise. The aim of this work is to assess the performance of decentralised velocity feedback control on lightweight sandwich panels.<br/>The first part of this thesis presents the theoretical model used to predict the structural response, sound radiation and sound transmission through active panels with decentralised velocity feedback loops. The model is then used in simulation studies on the intrinsic limitation of decentralised feedback control for thin homogeneous and sandwich active panels under distributed deterministic and stochastic excitations in the whole audio frequency range. The results suggest that decentralised velocity feedback control on lightweight sandwich panels is more efficient and can be applied over wider range of audio frequencies than for conventional thin homogeneous panels.<br/>The second part of this thesis presents experimental and simulation studies on a control system with five decentralised control units with proof-mass electrodynamic actuators, installed on conventional aluminium panel and a honeycomb sandwich panel. This study provides insight in the open and closed-loop response of the control units and gives a good understanding of the interaction between the panels and the control system. The results suggest that a practical control system that implements decentralised velocity feedback can offset some of the undesired sound transmission properties of lightweight sandwich structures by efficiently reducing structural vibration and sound power radiation in the mid audio frequency range.

Name dc:type.qualificationname

Ph.D.

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Southampton

Year dc:date.issued

2009

Author dc:creator

• Rohlfing, Jens

Advisors dc:contributor.advisor

• Gardonio, P.
• Thompson, D.J.