Locating Sound Sources Enclosed by a Solid Structure 2023-01-1077

Sound source localization has always been based on the assumption that the line of sight between a source and a sensor is unblocked. This assumption restricts the sound source localization in open space up to an obstacle or a boundary surface. Meanwhile, the root causes of most NVH issues are often housed inside a solid structure, for example, noise emission from an engine, a gearbox, etc. In a recent pioneering research project, however, we have shown that it is possible to use laser beams and photoacoustic sensors to determine the precise locations of a sound source enclosed inside a solid structure. , In this paper, we extend this research work by developing and consolidating the lasers and photoacoustic sensors into a portable system, known as LaSonics so that it will be easy to set up, simple to transport, and fast to obtain results. The major difference between LaSonics and any microphone is that the latter uses a piezoelectric sensor diagram to measure the acoustic pressure induced by an incoming sound wave in air; while the former uses collimated laser beams and photoacoustic sensors to simultaneously measure structural vibration and acoustic pressure, and Sonic Detection And Ranging (SODAR) , , One can view SODAR as a radar, except it is passive and uses sound waves. Consequently, LaSonics can see through a solid structure and hear acoustic signals, but a microphone cannot. Ultimately, we want to make LaSonics the selection of choice by engineers to tackle complex noise and vibration problems.