Passive and active interior noise control of box structures using the structural intensity method Z.S. Liu, H.P. Lee * , C. Lu Institute of High Performance Computing, 1 Science Park Road, #01-01, The Capricorn, Singapore Science Park II, Singapore 117528, Singapore Received 12 October 2004; received in revised form 4 March 2005; accepted 26 April 2005 Available online 29 June 2005 Abstract This paper presents passive and active vibro-acoustic noise control methods for attenuat- ing the interior noise level in box structures which can be an analogy of cabins of vehicle and aircraft. The structural intensity (SI) approach is adopted to identify the predominant vibration panels and interior noise sources for box structures. In the study, the finite element method is used to determine the structural vibration and structural intensity in the box surfaces. According to structural intensity vectors plot and structural intensity stream lines presentation, the possible effective control positions where the dampers may be attached and the active control forces may act to reduce vibration and interior noise, are identified. From the study, it can be demonstrated that the structural intensity approach and stream line presentation are possible methods for identifying the vibro-acoustic interior noise source and predominant panels which may be modified to reduce the interior noise level. The struc- tural intensity methodology, passive and active noise control results can be extended to the further study of the vibration and interior noise control of actual cabins of vehicles and aircraft. Ó 2005 Elsevier Ltd. All rights reserved. 0003-682X/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.apacoust.2005.04.010 * Corresponding author. Tel.: +65 6419 1303/1467; fax: +65 6778 0522/+65 6419 1480. E-mail addresses: liuzs@ihpc.a-star.edu.sg (Z.S. Liu), hplee@ihpc.a-star.edu.sg (H.P. Lee), luchun@ ihpc.a-star.edu.sg (C. Lu). Applied Acoustics 67 (2006) 112–134 www.elsevier.com/locate/apacoust