Cai Chenning, Chen Shaolin, Liu Lina
College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China.
Sensors (Basel). 2023 Oct 11;23(20):8382. doi: 10.3390/s23208382.
Concrete is among the most widely used structural materials in buildings and bridges all over the world. During their service life, concrete structures may inevitably display cracks due to long-term fatigue loads, leading to the degradation of structural integrity. Thus, it is very important to detect cracks and their growth in concrete structures using an automated structural health monitoring system. In this paper, experimental research on crack detection and imaging of concrete structures by using sensing skin and electrical resistance tomography (ERT) is presented. Carbon ink is screen-printed on the surface of concrete as a conductive material to form sensing skins. With these sensing skins, when cracks occur on or near the surface, it breaks the continuity of the sensing skins and significantly reduces conductivity in cracking areas. Then, after exciting small currents in sensing skins and measuring related voltage data, an inverse analysis based on total variation (TV) regularization is adopted to reconstruct tomographic images showing conductivity changes in sensing skins, to detect the occurrence and growth of cracks. The effectiveness of conductive sensing skins and our related crack detection method is validated in experimental studies on a concrete beam subjected to fatigue tests.
混凝土是世界范围内建筑和桥梁中使用最广泛的结构材料之一。在其使用寿命期间，混凝土结构可能会由于长期疲劳载荷而不可避免地出现裂缝，从而导致结构完整性下降。因此，使用自动化结构健康监测系统检测混凝土结构中的裂缝及其扩展情况非常重要。本文介绍了利用传感表皮和电阻层析成像（ERT）对混凝土结构进行裂缝检测和成像的实验研究。将碳墨作为导电材料丝网印刷在混凝土表面以形成传感表皮。借助这些传感表皮，当表面或其附近出现裂缝时，会破坏传感表皮的连续性，并显著降低裂缝区域的导电性。然后，在传感表皮中施加小电流并测量相关电压数据后，采用基于总变分（TV）正则化的反演分析来重建显示传感表皮电导率变化的层析图像，以检测裂缝的出现和扩展。在对一根承受疲劳试验的混凝土梁进行的实验研究中，验证了导电传感表皮和我们相关裂缝检测方法的有效性。
