Fiber-reinforced polymer (FRP) has been extensively used in civil engineering to enhance the strength and durability of concrete structures. Developing a reliable, practical, and cost-effective method for monitoring and assessing the integrity of FRP-confined concrete is essential. However, due to the heterogeneous nature of materials and the potential for delamination, damage evolution in FRP-wrapped concrete is complex, limiting the effectiveness of some traditional structural health monitoring (SHM) techniques. This study proposes a piezoceramic-based approach for real-time monitoring and evaluation of microcracking behavior in FRP-reinforced concrete members. A piezoceramic sensor array is utilized to capture stress-wave responses from the structure. Based on wave propagation characteristics in concrete, diffusion theory and the Akaike information criterion (AIC) are employed for data analysis. To validate the proposed method, concrete columns with different FRP confinement configurations were subjected to cyclic loading to monitor microcrack development. The results demonstrate that P-wave velocity and diffusivity effectively reflect microcracking behavior. Their variations indicate stiffness degradation and can accurately identify potential zones of FRP rupture.

中文翻译：

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使用弥散超声监测 FRP 包裹混凝土中的微裂纹演变

纤维增强聚合物 （FRP） 已广泛用于土木工程，以提高混凝土结构的强度和耐久性。开发一种可靠、实用且具有成本效益的方法来监测和评估 FRP 约束混凝土的完整性至关重要。然而，由于材料的异质性和分层的可能性，FRP 包裹混凝土的损伤演变很复杂，限制了一些传统结构健康监测 （SHM） 技术的有效性。本研究提出了一种基于压电陶瓷的方法，用于实时监测和评估 FRP 增强混凝土构件中的微开裂行为。压电陶瓷传感器阵列用于捕获结构中的应力波响应。基于波在混凝土中的传播特性，采用扩散理论和 Akaike 信息准则 （AIC） 进行数据分析。为了验证所提出的方法，具有不同 FRP 约束配置的混凝土柱受到循环载荷以监测微裂纹的发展。结果表明，P 波速度和扩散率有效地反映了微裂纹行为。它们的变化表明刚度退化，并且可以准确识别 FRP 破裂的潜在区域。