Interfacial debonding defects in rectangular steel–concrete composite structures (RSCCS) can significantly diminish the confinement effect of the steel on the concrete core and reduce load transfer efficiency, potentially impacting the overall performance of the structure. Detection of these defects in RSCCS is therefore considered critical. This study investigates the complexities of stress wave propagation in heterogeneous media, focusing on detecting and tomographically imaging interfacial debonding defects in RSCCS cross-sections with mesoscale concrete structures. An efficient polygonal aggregate modeling method is proposed to enhance the efficiency of collision detection, and an improved first arrival time algorithm (FATA) based on the Akaike information criterion (AIC) is developed to improve the accuracy of extracting the first arrival time of stress waves. Additionally, a random walk algorithm (RWA) based onSnell law is introduced to address accuracy issues related to the theoretical shortest ray path of stress waves. A finite element model of an RSCCS containing interfacial debonding defects and various aggregate distributions was constructed. By simulating the stress wave field in mesoscale models and their corresponding RSCCS model with homogeneous concrete, the study validated the feasibility of stress wave measurements and confirmed the significant influence of interfacial debonding defects. The FATA method was then applied to analyze the first wave arrival times, and the internal linkage mechanisms of the first peak amplitude of stress wave and wavelet packet energy were thoroughly explored. Using the simultaneous iterative reconstruction technique (SIRT) algorithm, the initial velocity model was iteratively optimized by comparing the extracted stress wave first arrival times with theoretical shortest ray path propagation times. Numerical simulations and experimental results demonstrate that the proposed method can accurately identify the location and depth of interfacial debonding defects within heterogeneous concrete core at the mesoscale, providing an effective non-destructive testing and evaluation technique for RSCCS.

中文翻译：

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应力波 CT 成像方法检测中尺度 RSCCS 界面脱粘缺陷


矩形钢-混凝土复合结构 （RSCCS） 中的界面脱粘缺陷会显著降低钢材对混凝土芯材的约束效应，降低载荷传递效率，从而可能影响结构的整体性能。因此，在 RSCCS 中检测这些缺陷被认为至关重要。本研究调查了应力波在异质介质中传播的复杂性，重点是检测和断层成像具有中尺度混凝土结构的 RSCCS 横截面中的界面脱粘缺陷。为提高碰撞检测效率，提出了一种高效的多边形聚集建模方法，并开发了一种基于 Akaike 信息准则 （AIC） 的改进首次到达时间算法 （FATA），以提高提取应力波首次到达时间的准确性。此外，该文还引入了一种基于斯涅尔定律的随机游走算法 （RWA），以解决与应力波理论最短射线路径相关的精度问题。构建了包含界面脱键缺陷和各种聚集体分布的 RSCCS 有限元模型。通过模拟均质混凝土中尺度模型中的应力波场及其相应的 RSCCS 模型，该研究验证了应力波测量的可行性，并证实了界面脱粘缺陷的显着影响。然后，应用 FATA 方法分析第一波到达时间，深入探究应力波第一峰幅值和小波包能量的内部联系机制。 使用同步迭代重建技术 （SIRT） 算法，通过将提取的应力波首次到达时间与理论最短射线路径传播时间进行比较，对初始速度模型进行迭代优化。数值模拟和实验结果表明，所提方法能够在介尺度上准确识别非均质混凝土核心内界面脱粘缺陷的位置和深度，为RSCCS提供了一种有效的无损检测和评价技术。