A Literature Review of Non-Contact Tools and Methods in Structural Health Monitoring

Abstract

In this review paper, the methodology employed was undertaken according to the following steps. First, the literature was collected from the SCOPUS database due to it indexes the largest number of journals and is commonly used in engineering fields [12,13]. The initial search was performed on the 21st of January 2021 with the keywords "structural health monitoring" and with the aim of obtaining exclusively the non-contact literature, the specific query was: TITLE-ABS-KEY ("structural health monitoring" AND non-contact* OR noncontact* OR contactless). The boolean operators (AND, OR, *) are used to include entirely the non-contact literature and to incorporate potential literature with different spellings of non-contact. An initial 623 results were obtained, a further limit was imposed on only English language documents. The search was not limited to a time frame, resulting in 608 documents from 1994 to 2021 plotted in Figure 1. Then, the 608 articles were browsed and 92 irrelevant documents (e.g., medical fields) were excluded and subsequently were classified according to the main method/tool, Table 1 summarizes it. Figure 1: Research publications on the use of non-contact methods and tools in structural health monitoring.Table 1: Non-contact methods/tools in SHM. Methods Number of Articles Percentage Vision-based 146 28.29% Guided Waves 91 17.64% Ultrasound 49 9.50% Vibration 47 9.11% Magnetic Methods 33 6.40% Acoustic based 31 6.01% Displacement based 28 5.43% Thermal Inspection 18 3.49%

Structural health monitoring of inland navigation structures and ports: a review on developments and challenges

“…Contact sensors require time-consuming installation, environmental protection, regular maintenance, and repairs, which can be overcome using noncontact sensors/sensing. 96 Non-contact sensing offers collecting many types of measurements. For example, temperature and displacements can be measured without coming into the contact with the host structure, thus enabling SHM at both local and global levels.…”

Integration of Bridge Health Monitoring System With Augmented Reality Application Developed Using 3D Game Engine–Case Study

“…In addition to this, the measurement of vertical displacement is also an important parameter for the health evaluation of bridges and it is convenient to measure it directly on long-span bridges. Therefore, Liquid Levelling Sensors (LLS) are considered the most suitable and promising devices for this kind of measurement [17], which can overcome the problem of inclination angles and provide the most accurate results [18]. Moreover, measurement of linear deflection is also important as many of the sensors do not satisfy the field measurement criteria, so, for this purpose, Linear Variable Differential Transformers (LVDT) are the best-suited devices that can be reliable for field measurement of linear displacement for a longer period of time [19].…”

Analysis of Acid Diffusion Effects on Physical Properties of Polymer Composites: A Combined Study of Mechanical and Electrical Characterization

“…Moreover, SHM approaches that detect chemical diffusion in composites are primarily based on changes in volume and weight measurements. However, these methods are impractical as they require disassembly of the structures [9,23]. Therefore, exploring different effects of the diffusion process might be beneficial.…”