A diffuse acoustic field has been increasingly used to infer temporal changes in the structures,such as early dislo-cations and microcracking.This study explores three different techniques to characterise acoustic fie...A diffuse acoustic field has been increasingly used to infer temporal changes in the structures,such as early dislo-cations and microcracking.This study explores three different techniques to characterise acoustic field by using a single ultrasonic phased array.The first two techniques are proposed to measure spatial uniformity of wave field by examining differences in the integral of energy and the maximum energy respectively at multiple inspection loca-tions.The third one is developed to evaluate the degree of phase coherence between propagating waves transmitted sequentially by two neighbouring array elements.The efficacy of these techniques are investigated by examining their metrics on simulations and well-known samples.The results suggest that two selected metrics can be used to quantitatively estimate the diffuse field start time as well as the field size by comparing their value with the idealised diffuse state(15%for the energy integral metric,ηarea and 1 for the phase coherence metric,ηphase)and identifying the convergence start point.展开更多
基金Supported by Anhui Provincial Natural Science Foundation of China(Grant No.2008085J24)Anhui Provincial Science and Technology Major Project of China(Grant No.201903a05020010)+2 种基金Young Talent Support Program of China Association for Science and Technology(Grant No.[2020]No.87)Doctoral Science and Technology Foundation of Hefei General Machinery Research Institute(Grant No.2019010381)Anhui Provincial Key Research and Development Plan of China(Grant No.202004a05020003).
文摘A diffuse acoustic field has been increasingly used to infer temporal changes in the structures,such as early dislo-cations and microcracking.This study explores three different techniques to characterise acoustic field by using a single ultrasonic phased array.The first two techniques are proposed to measure spatial uniformity of wave field by examining differences in the integral of energy and the maximum energy respectively at multiple inspection loca-tions.The third one is developed to evaluate the degree of phase coherence between propagating waves transmitted sequentially by two neighbouring array elements.The efficacy of these techniques are investigated by examining their metrics on simulations and well-known samples.The results suggest that two selected metrics can be used to quantitatively estimate the diffuse field start time as well as the field size by comparing their value with the idealised diffuse state(15%for the energy integral metric,ηarea and 1 for the phase coherence metric,ηphase)and identifying the convergence start point.
