title: Improving accuracy of acoustic source localization in anisotropic plates.
abstract: The acoustic source localization technique for anisotropic plates proposed by the authors in an earlier publication ([1] Kundu et al., 2012) is improved in this paper by adopting some modifications. The improvements are experimentally verified on anisotropic flat and curved composite plates. Difficulties associated with the original technique were first investigated before making any modification. It was noted that the accuracy of this technique depends strongly on the accuracy of the measured time difference of arrivals (TDOA) at different receiving sensors placed in close proximity in a sensor cluster. The sensor cluster is needed to obtain the direction of the acoustic source without knowing the material properties of the plate. Two modifications are proposed to obtain the accurate TDOA. The first one is to replace the recorded full time histories by only their initial parts - the first dip and peak - for the subsequent signal processing. The second modification is to place the sensors in the sensor cluster as close as possible. It is shown that the predictions are improved significantly with these modifications. These modifications are then applied to another sensor cluster based technique called the beamforming technique, to see if similar improvements are achieved for that technique also with these modifications.
authors.affiliation: Department of Mechanical & Physical Engineering, Graduate School of Engineering, Osaka City University, 558-8585 Osaka, Japan. Electronic address: hayatonakatani@imat.eng.osaka-cu.ac.jp.
authors.forename: Hayato
authors.initials: H
authors.lastname: Nakatani
authors.affiliation: Department of Civil Engineering and Engineering Mechanics, University of Arizona, Tucson, AZ 85721, USA. Electronic address: tkundu@email.arizona.edu.
authors.forename: Tribikram
authors.initials: T
authors.lastname: Kundu
authors.affiliation: Department of Advanced Energy, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561 Chiba, Japan. Electronic address: takeda@smart.k.u-tokyo.ac.jp.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Takeda
keywords: Acoustic source localization; Anisotropic structure; Guided wave; Lamb wave; Passive monitoring