联合改进作用距离和Dijkstra算法的复杂结构声发射定位方法及应用

声发射定位对含空区等复杂结构的连续动态安全监测具有重要意义。针对直线路径定位方法不适用于复杂结构，而常规Dijkstra搜索算法常出现局部最优路径等问题，提出了一种联合改进作用距离和Dijkstra算法的声发射定位方法，实现复杂结构下声发射的高精度定位。理论测试显示：基于改进作用距离的Dijkstra算法得到的P波传播路径长度小于等于常规作用距离的Dijkstra算法，即P波走时更为准确。理论测试和断铅试验定位测试表明：本文提出的定位方法在复杂结构声发射定位时的整体误差在0.50 cm范围之内，断铅事件平均定位误差由常规作用距离Dijkstra算法的0.95 cm下降至本文的0.54 cm。改进的声发射定位方法在复杂结构声发射定位方面具有很好的应用前景。

Acoustic Emission Localization Method for Complex Structure Based on Improved Interaction Distance and Dijkstra Algorithm and Its Application

Acoustic emission source location plays an important role in the continuous dynamic safety monitoring of complex structures which contain empty zones. The straight path-based location method can’t be applied in a complex structure， and the existing Dijkstra search algorithm can obtain optimal local paths. This study improves the calculation method of the distance between two points： if the line determined by two points does not intersect the obstacle， the straight line distance between the two points is the reachable distance of two points， and the other ways are recorded as infinity.To solve this problem， an acoustic emission location method based on improved interaction distance and Dijkstra algorithm was proposed in this study. It uses the double-difference method to establish the positioning objective function and the mesh method to calculate the fitting error of the positioning objective function of each grid point， and takes the corresponding point of the minimum fit error as the positioning result， which to achieve a high-precision acoustic emission location in a complex structure. Tests were carried out with complex structures with rectangles， triangles， and circles and structures with single round holes. The results indicate that the P wave propagation path obtained by the Dijkstra algorithm with improved interaction distance is less than or equal to that obtained by the traditional Dijkstra algorithm. And the P wave propagation path containing the round pore structure is very close to the theoretical propagation distance. In other words， the P wave travel time based on improved interaction distance is more reliable. After adding 3us Gaussian noise to the theory， the positioning error of the conventional method reached 1.5cm， but the location method proposed in this study has an overall location error within 0.50 cm for complex structures. It shows that the proposed method has good robustness. Further， the lead-breaking experiment was carried out on the rectangular （30 cm×20 cm） granite sample containing a round hole （D=2.5 cm）. After the double-difference method was used to remove the P wave initial to systematic error， the positioning error of the conventional method was mainly 0.5 to 1.5 cm， and the overall error of the positioning method in this paper was within the range of 0.50 cm， and the average positioning error for the lead breaking events from 0.95 cm of traditional Dijkstra algorithm to 0.54 cm for PLB events， which indicates that the proposed method has a good application prospect for complex structures.