Using Air-Coupled Sensors To Measure Depth Of A Surface-Breaking Crack In Concrete
MetadataShow full item record
Previous studies show that surface wave transmission ratio across a surface breaking crack in concrete can be used as an indicator of the crack depth. However, due to inconsistent sensor coupling condition on rough concrete surface, reliable measurement of the transmission ratio is still a challenging task. In this study, the air-coupled sensing method is proposed as a solution to this problem. Without direct contact between sensors and the testing surface, the air-coupled sensing not only allows rapid testing speed, but also enables more consistent signal measurement owing to removal of sensor coupling variation. The latter feature is especially valuable to wave transmission measurement. This paper first presents results from a numerical analysis (FEM model). Based on the results, a simplified algorithm is proposed for surface wave transmission ratio calculation. A calibration curve between the transmission ratio and normalized crack depth (actual crack depth/wavelength) is obtained. Experimental study using the air-coupled sensing method verifies the validity of the curve.