Abstract
The Lamb wave-based Scanning Laser Doppler Vibrometry (SLDV) method using continuous excitation is a promising method for visualizing defects in plate-like structures. To visualize defects, the A0 mode is commonly used because of its sensitivity to the thickness variations, i.e. wave speed changes according to the thickness. However, for thick plates, the A0 mode is found to be less sensitive to thickness variations compared to thin structures. Recently, to address this issue, inter-digital transducer (IDT)-based SLDV is introduced to efficiently generate the symmetric mode for damage detection of thick plates. It was demonstrated that the detectability of shallow defects using IDT-based SLDV in a thick plate was improved to that when using the A0 mode. However, it is hard to cover whole thickness (0.3 ~ 6 mm thickness) of a carbon steel plate of 6-mm thickness with a tapered defect using a single symmetric mode. To measure whole range of thickness of the carbon steel plate, multi-frequency excitation is needed based on analysis of wavenumber sensitivity and degree of separation between mode (DSM). It is demonstrated that the detectability of defects in a thick plate using IDT-based SLDV is improved compared to that when using the single S0 mode.
How to Cite:
Kang, T. ., Moon, S. ., Han, S. ., Young, J. . & Park, G. ., (2019) “Multi-frequency wavenumber analysis of wall-thinned metal plates with IDT-based SLDV”, Review of Progress in Quantitative Nondestructive Evaluation .
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