堆石坝面板声发射源组合定位方法
Pattern recognition combination model for locating damage in concrete faced rockfill dams using acoustic emission and its experimental verification
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摘要: 堆石坝上游侧的混凝土面板是关乎大坝安全的重要防渗结构。针对现有声发射源定位方法在大尺度、时变性结构中定位效率与精度的不足,提出了一种兼顾大尺度与波速扰动影响的声发射源组合定位方法。首先,为减少声发射源定位计算中的无关搜索域,发展了一种分布式声发射传感器阵列,并基于各声发射传感器到时权重,建立了关于子监测阵列快速识别与声发射源区域二次细分的控制方程。其次,为进一步提高声发射源定位精度,改进了传统灰狼算法,并以细分的声发射源区域作为搜索域,以波速作为未知量,发展了一种基于改进灰狼算法的未知波速下声发射源定位方法。混凝土面板上的断铅试验结果表明:本文定位方法有效减少了至少75%的无关搜索域,且定位精度优于已知波速的声发射源定位方法,为水工结构健康监测提供了有益参考。Abstract: A combined pattern recognition model that comprises a localization method for the domains and space coordinates of acoustic emission sources is presented. First, to reduce the irrelevant domain searching, we decompose the monitoring data of the whole structure health into an array of multiple submonitoring acoustic emission sensors, and formulate a control equation for the rapid identification of the array and subdivision of the acoustic emission source area. Then, a strategy for nonlinear variations and the Lévy random flight step is adopted in the calculation of the control parameters to improve global searching ability and avoid falling into local optimizations in application of the Gray Wolf Optimizer(GWO) algorithm. Wave speed is regarded as a variable and the improved GWO is used to localize those acoustic emission sources with unknown wave speeds in the source sub-domains aforementioned. The results of pencil lead broken test on a concrete slab show that this method has a positioning accuracy higher than that of the Least Square, LS-Geiger, or GWO localization algorithm, and it is effective in detecting damage in hydraulic concrete slab structures.