Second Harmonic Detection Generated from Fastened Bolt
The second harmonic components before/after the bolt was fastened were detected by using double-layered piezoelectric transducer (DLPT). The resonance frequency of DLPT changes to 1 MHz (f 0/2) when connected in parallel, but remains at 2 MHz (f 0) when connected in series. An effective fundamental transmission (1 MHz) is obtained when the DLPT is electrically connected in parallel while efficient second harmonic reception (2 MHz) is obtained when the DLPT is connected in series. In our system, the pulse inversion averaging (PIA) method was applied to enhance the second harmonic component. A hexagon head bolt (the diameter of a screw: 12 mm, the length: 100 mm) was used in experimental. The bolt was fastened by 40 N-m. The detected second harmonic component after the bolt was fastened was increased by approximately 10 dB compared with before the bolt was fastened.
KeywordsFastened bolt Second harmonic Pulse wave Non-destructive testing Double-layered piezoelectric transducer Pulse echo
This work was supported by Grant-in-Aid for Young Scientists (Start-up) (No. 20860020) from Japan Society for the Promotion of Science.
- 1.Sakai, T.: Zouho Neji Teiketsu Gairon, pp. 108–114. Yokendo Ltd., Tokyo (2005) [in Japanese]Google Scholar
- 2.Ogi, H., Hirao, M., Yasui, H.: Ultrasonic measurement of bolt-axial stress by a shear-wave electromagnetic acoustic transducer. Hihakai Kensa 47(5), 331–336 (1998) [in Japanese]Google Scholar
- 3.Kurosaki, S., Sasaki, Y., Izumi, S.: Trial of measurements for axial force of bolt using piezo cable. Hihakai Kensa 56(7), 149–154 (2007) [in Japanese]Google Scholar
- 4.Okugawa, M., Egawa, K.: Study on smart washer using piezoelectric material for bolt loosening detection. Hihakai Kensa 52(9), 511–516 (2003) [in Japanese]Google Scholar
- 7.Cantrell, J.H.: Dependence of microelastic-plastic nonlinearity of martensitic stainless steel on fatigue damage accumulation. J. Appl. Phys. 100(063508), 1–7 (2006)Google Scholar
- 15.Simm, F.C.: Phase inversion wideband non-linear imaging: Applications to tissue harmonic imaging. J. Med. Ultrason. 26(4), 285 (1999)Google Scholar