Coupling the force analysis technique and full-field vibration measurements for the identification of a time-space-varying sound pressure loading on a membrane

Abstract

This work is grounded on the force analysis technique, an identification method that directly uses a structure's equation of motion to formulate an inverse problem, explicitly identifying the force causing the structure's motion. Prior research employing this technique has been predominantly conducted in the frequency domain and was limited to stationary, mechanical excitations using physical sensor arrays such as accelerometers. The objective of this research was mostly quantitative (amplitude, location), while the proposed approach is rather qualitative identification. Indeed and by combining the force analysis technique with full-field and non-contact vibration measurements conducted on a system, here a membrane, this communication describes a proof-of-concept for the identification of a time-space-varying sound pressure loading. A compact and tonal sound source is used to draw freehand shapes against the membrane surface, and the objective is to follow/reconstruct the trajectory followed by this source. Results are provided for different drawn shapes or letters, and the effect of mechanical or calculation parameters on the reconstructed information is studied. Finally, potential research directions are discussed and fed by preliminary measurements on a percussion instrument.