Mointoring Thickness Deviations in Planar Multi-Layered Elastic Structures Using Impedance Signatures

Fisher, K A

Lawrence Livermore National Laboratory

关键词: Transducers;    Monitoring;    Thickness;    Detection;    Ultrasonic Waves;   

DOI  :  10.2172/914620
RP-ID  :  UCRL-TR-229538
RP-ID  :  W-7405-ENG-48
RP-ID  :  914620

美国|英语

来源: UNT Digital Library

【 摘 要 】

In this letter, a low frequency ultrasonic resonance technique that operates in the (20 - 80 kHz) regime is presented that demonstrates detection of thickness changes on the order of +/- 10{micro}m. This measurement capability is a result of the direct correlation between the electrical impedance of an electro-acoustic transducer and the mechanical loading it experiences when placed in contact with a layered elastic structure. The relative frequency shifts of the resonances peaks can be estimated through a simple one-dimensional transmission model. Separate experimental measurements confirm this technique to be sensitive to subtle changes in the underlying layered elastic structure.