Placement Technique of Measurement Points for Inverse Acoustic Analysis 2015-32-0747

This paper describes a measurement points' placement technique for the sound source identification using inverse acoustic analysis. In order to reduce noise in NVH problem for various kinds of machines including small size engine, it is necessary to identify the sound source. The inverse acoustic analysis is a technique that is effective for the sound source identification.[1,2] The inverse acoustic analysis identifies a surface vibration of an object by measuring the radiated sound and solving the inverse problem. Nakano et al. researched about the location of sound pressure measurement points for accurate improvement.[3] They clarified that the sound pressure measurement points on the concentric circle gave more accurate surface vibration than the measurement points on the square lattice. In this paper, we proposed a measurement points' placement technique based on the space filling design.[4,5] The placement of the measurement points with the space filling design has the following merits; (1) Enables to decide a number of measurement points according to the experiment. This characteristic is superior to location on the square lattice. (2) Enables to predict the surface vibration of a rectangular object. This characteristic is superior to location on the concentric circle. In this paper, we show that the precision of the measurement points' placement with the space filling design and the measurement points' placement by the conventional technique are at the same level. Furthermore, the design criterions of space filling design are discussed from the viewpoint of the measurement points' location and the optimization of design criterion is discussed to locate measurement points.