Abstract
This work proposes a nonlinear dual frequency (modulated) phased array technique for fatigue crack evaluation in aluminium and metallic structures, and near field enhancement in composite materials. A standard ultrasound system with multiple transmitting and receiving elements was used to excite an aluminium fatigue sample and impacted composite plate with two frequencies. The method relied on the evaluation of harmonic sidebands which can be correlated to defects/damage in materials, with nonlinear methods having shown increased sensitivity versus standard techniques. An initial pump frequency (f2) is used to initialize a - breathing/ringing' crack after which a second frequency (f1) is used to further excite the cracked region and generate sidebands from the modulated frequencies. This method relies on both an amplitude and frequency subtraction techniques to filter out linear ultrasound effects. One of the benefits of modulation techniques in general are reduction of equipment based nonlinearities, commonly produced when conducting single frequency tests. An aluminium coupon with a closed fatigue crack was evaluated using single and dual frequency methods. The results showed that the dual frequency excitation method was able to more accurately define the extent of the crack and improved accuracy versus standard phased array techniques.
Original language | English |
---|---|
Title of host publication | Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XIII |
Editors | Andrew L. Gyekenyesi, Tzu-Yang Yu, H. Felix Wu, Peter J. Shull |
Publisher | SPIE |
ISBN (Electronic) | 9781510625976 |
DOIs | |
Publication status | Published - 1 Jan 2019 |
Event | Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XIII 2019 - Denver, USA United States Duration: 4 Mar 2019 → 7 Mar 2019 |
Publication series
Name | Proceedings of SPIE - The International Society for Optical Engineering |
---|---|
Volume | 10971 |
ISSN (Print) | 0277-786X |
ISSN (Electronic) | 1996-756X |
Conference
Conference | Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XIII 2019 |
---|---|
Country/Territory | USA United States |
City | Denver |
Period | 4/03/19 → 7/03/19 |
Funding
This paper has been funded by the EXTREME project of the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 636549.
Keywords
- BVID
- Composite
- Damage
- Defects
- Fatigue
- Modulation
- Nonlinear Imaging
- Nonlinear Ultrasound
- Phased Array
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering