Broadband Laser Ultrasonic Excitation and Multi-band Sensing for Hierarchical Automatic Damage Visualization
- 3 Downloads
It is well known that the selection of a frequency for signal generation and data acquisition significantly affects the quality of ultrasonic or laser ultrasonic nondestructive testing (NDT) results, and the analog filter is essential to prevent the aliasing effect. This paper presents a systematic approach using a hierarchical inspection scheme for automatic inspection processes. A frequency band divider (FBD) with a single-input–multiple-output (SIMO) system was newly created to examine quickly various frequency ranges at single scanning using laser-based broadband excitation. The FBD was implemented into a pulse-echo ultrasonic propagation imaging (PE UPI) system capable of fully noncontact laser ultrasonic inspection. Only two scans are required to determine the optimal frequency range for unknown specimens. This tremendously reduces the number of scanning trials for the investigation of complete frequency ranges.
KeywordsHierarchical approach Nondestructive testing Pulse-echo ultrasonic propagation imager Programmable band-pass filter
The work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Ministry of Science and ICT (NRF-2017R1A5A1015311) and the Boeing Company.
- 2.Gibson RF (2012) Principles of composite material mechanics. CRC Press, Boca RatonGoogle Scholar
- 5.Scruby CB, Drain LE (1990) Laser ultrasonics techniques and applications. Hilger, BristolGoogle Scholar
- 7.Lee JR, Jang JK, Kong CW (2014) Fully noncontact wave propagation imaging in an immersed metallic plate with a crack. Shock Vib 2014:1–8Google Scholar
- 16.Smith SW (1997) The scientist and engineer’s guide to digital signal processing. California Technical Pub, San DiegoGoogle Scholar
- 17.Mancini R (2003) Op amps for everyone: design reference. Newnes, AmsterdamGoogle Scholar