ACTIVE CONTROL OF VIBRATION TRANSMISSION IN A CYLINDRICAL-SHELL

The theoretical analysis of active control of harmonic power transmiss ion in a semi-infinite cylinder using a circumferential array of contr ol forces and a circumferential array of error sensors is considered, and the extent of control which is achievable for a realistic control force configuration is examined.The model considered is a semi-infinit e cylinder, simply supported at one end, anechoically terminated at th e other end and excited harmonically by an array of in-phase primary f orces arranged in a line around its circumference. Control is achieved by an array of independent control forces applied downstream from the primary forces. For three or more control forces it is possible to ac hieve a power transmission reduction of 30 dB for both acceleration an d power transmission cost functions, provided that the error sensors a re in the far field of the primary and control forces. (C) 1997 Academ ic Press Limited.