网格划分对混凝土超声波CT成像的影响  

Effect of meshing on concrete ultrasonic CT imaging

作　　者：龙士国 肖顺芳 LONG Shiguo XIAO Shunfang(School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, China)

机构地区：[1]湘潭大学材料科学与工程学院,湖南湘潭411105

出　　处：《武汉大学学报（工学版）》2017年第5期708-713,共6页Engineering Journal of Wuhan University

摘　　要：超声波CT成像技术是一种较好的检测混凝土内部缺陷的方法,采用Snell定律修正图像,建立一种低速异常区域的混凝土模型——矩形(0.4m×0.5m),通过划分不同的网格,并比较两种网格模型的直射线追踪、一次射线追踪、二次射线追踪的路径情况,通过分析误差得出最合适的反演网格数.研究表明,当采用左右检测方式时,在正演划分的水平和竖直网格数相等的情况下,最合适的反演的网格数应选择:290/正演网格数.代数重建技术(ART)反演情况较好地印证了这个结论,且二次射线追踪的误差最小,反演的效果最为接近模型的真实情况,较为精确地反映了混凝土模型的内部缺陷情况,表明网格的划分合适与否对CT成像的精度有很大影响.Ultrasonic computerized tomography （CT） imaging is a significant method for detecting defects inside the concrete. By using Snell principle corrected image, a low velocity zone concrete models of rectangles（0.4 m×0.5 m） is built. The paths of line tracing, once ray tracing and secondary ray tracing of the two grid models are compared by dividing different network cells. The most appropriate grid inversion number could be obtained by analyzing the error. The results demonstrate that in the case of forward hori- zontal and vertical grid of the division of equal number of meshes, the most suitable inversion for selecting is 290/forward grid number,when the left and right detection method is used. This conclusion is confirmed by algebraic reconstruction technique （ART） inversion significantly. The error of secondary ray tracing is the smallest; and the inversion effect is the closest to the real situation of the model. The situation inside the concrete model of the defect is reflected more accurately, which indicates that a suitable meshing has a great influence on the accuracy of CT imaging.

关 键 词：混凝土 超声波 CT 代数重建技术(ART) Snell 

分 类 号：TU528.571[建筑科学—建筑技术科学]