Abstract
Nonlinear ultrasonics has been shown to be sensitive to microscale damage, lattice defects, and microstructural changes induced due to thermal and mechanical loading. The most well-known technique for evaluating the nonlinear properties of solids is harmonic generation. However, traditionally, harmonic generation has been limited to contact transducers and single point measurements. The present work explores the use of immersion piezoelectric transducers to measure the nonlinearity parameter of solids immersed in a fluid. This enables us to perform a nonlinear immersion C-Scan, which can be further used to localize defects or nonlinear sources. Nonlinear harmonic imaging of two cases will be demonstrated. The 1st case uses a low carbon steel bar subjected to full reversed bending, thus creating localized plastic zones. The 2nd case uses A302 steel bar subjected to plastic deformation and local heat treatment. Harmonic imaging of both cases show that nonlinear sources can be localized. The challenges which act as roadblock going towards to a complete tool are also highlighted.
How to Cite:
Huanes-Alvan, G., Chakrapani, S., Barnard, D., Huanes-Alvan, G., Chakrapani, S. & Barnard, D., (2019) “Nonlinear harmonic imaging of solids using nonlinear immersion ultrasonics”, Review of Progress in Quantitative Nondestructive Evaluation .
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