Modal structural acoustic sensing with minimum number of optimally placed piezoelectric sensors

Structural acoustic sensing is a method of obtaining radiated sound pressure from a vibrating structure using vibration information. Structural acoustic sensing is used in active structural acoustic control for attenuating the sound radiated from a structure. In this paper, a new approach called Modal Structural Acoustic Sensing (MSAS) is proposed for estimating the pressure radiated from a vibrating cylindrical shell using piezoelectric sensors. The motion equations of a cylindrical shell in conjunction with piezoelectric patches are derived based on the Donnel-Mushtari shell theory. The locations of the piezoelectric sensors are optimized by the Genetic Algorithm based on maximizing the observability gramian matrix. The Kirchhoff-Helmholtz integral is used for estimating the sound pressure radiated from the cylindrical shell. Numerical simulations are performed to demonstrate the advantages of the proposed approach in comparison with previous methods such as discrete structural acoustic sensing and distributed modal sensors. Results show that the MSAS can increase the estimation accuracy and decrease the controller dimensionality and the number of required sensors.