Clauß Felix, Epple Niklas, Ahrens Mark Alexander, Niederleithinger Ernst, Mark Peter
Institute of Concrete Structures, Faculty of Civil and Environmental Engineering, Ruhr University Bochum, Universitätstraße 150, 44801 Bochum, Germany.
Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
Materials (Basel). 2022 Jan 19;15(3):738. doi: 10.3390/ma15030738.
The integral collection of information such as strains, cracks, or temperatures by ultrasound offers the best prerequisites to monitor structures during their lifetime. In this paper, a novel approach is proposed which uses the collected information in the coda of ultrasonic signals to infer the condition of a structure. This approach is derived from component tests on a reinforced concrete beam subjected to four-point bending in the lab at Ruhr University Bochum. In addition to ultrasonic measurements, strain of the reinforcement is measured with fiber optic sensors. Approached by the methods of moment-curvature relations, the steel strains serve as a reference for velocity changes of the coda waves. In particular, a correlation between the relative velocity change and the average steel strain in the reinforcement is derived that covers 90% of the total bearing capacity. The purely empirical model yields a linear function with a high level of accuracy (R2=0.99, RMSE≈90μstrain).
通过超声波对诸如应变、裂缝或温度等信息进行整体收集，为在结构的整个生命周期内对其进行监测提供了最佳前提条件。本文提出了一种新颖的方法，该方法利用超声信号尾波中收集到的信息来推断结构的状况。此方法源自于在波鸿鲁尔大学实验室对一根承受四点弯曲的钢筋混凝土梁进行的构件试验。除了超声测量外，还使用光纤传感器测量了钢筋的应变。通过弯矩 - 曲率关系方法，钢筋应变作为尾波速度变化的参考。特别地，得出了相对速度变化与钢筋中平均钢筋应变之间的相关性，该相关性涵盖了总承载能力的90%。这个纯经验模型产生了一个具有高精度的线性函数（R2 = 0.99，RMSE≈90微应变）。
