Nondestructive evaluation of optical fiber splices and connectors

1992 ◽  
Author(s):  
T. Wei ◽  
D. J. Cotter ◽  
B. T. Devlin ◽  
W. D. Koenigsberg
Keyword(s):  
Optical Fiber ◽  
Nondestructive Evaluation

Ultrasonic Nondestructive Evaluation Methods Applicable to High-Temperature Environments Based on Optical Fiber Remote Sensing

2020 ◽  
Author(s):  
Yoji Okabe ◽  
Fengming Yu ◽  
Osamu Saito
Keyword(s):  
High Temperature ◽  
Optical Fiber ◽  
Nondestructive Evaluation ◽  
Guided Waves ◽  
Elevated Temperatures ◽  
Ceramic Plate ◽  
Sensing System ◽  
Heat Resistant ◽  
Propagation Behavior ◽  
Ultrasonic Sensing

Abstract The development of reliable heat-resistant structural materials requires nondestructive evaluation (NDE) techniques to evaluate the damage progress during material testing at elevated temperatures. Hence, our optical fiber ultrasonic sensing system with a phase-shifted fiber Bragg grating (PSFBG) sensor was improved to a remote AE measurement system at high temperature. The optical fiber was used as an ultrasonic waveguide from an object material in a high-temperature furnace to the PSFBG sensor placed far from the furnace. As a result, AE signals at about 1000°C were successfully detected keeping their precise waveform. Therefore this method will be useful to evaluate the damage progress in heat-resistant materials under high temperature. Furthermore, the remote PSFBG ultrasonic sensing system was incorporated into the receiving part of a laser ultrasonic visualizing inspector (LUVI) for a high-temperature NDE. The LUVI can visualize the propagation behavior of ultrasonic guided waves in complex shape structures. As a result, the improved LUVI with the optical fiber ultrasonic receiver succeeded in clear visualization of the ultrasonic wave propagation in a ceramic plate at 1000°C. Then an artificial damage formed in the ceramic plate was able to be detected by the observation of reflection waves from the damage. Hence, this system has a potential as an effective and intuitive NDE method in high-temperature environments.

Bending loss formulas for step-index optical fiber and their applicable regions

1981 ◽  
Vol 64 (10) ◽  
pp. 95-103
Author(s):  
Kiyonobu Kusano ◽  
Shigeo Nishida
Keyword(s):  
Optical Fiber ◽  
Step Index ◽  
Bending Loss

Effects of contact gap on nondestructive evaluation using magnetic measurement for ferromagnetic steel

2020 ◽  
Vol 64 (1-4) ◽  
pp. 969-975
Author(s):  
Hiroaki Kikuchi ◽  
Yuki Sato
Keyword(s):  
Magnetic Flux ◽  
Nondestructive Evaluation ◽  
Effective Permeability ◽  
Magnetic Circuit ◽  
Magnetic Measurement ◽  
Air Gap ◽  
Motive Force ◽  
Hysteresis Curve ◽  
Evaluation Technique ◽  
Ferromagnetic Steel

We investigated effects of contact gap on magnetic nondestructive evaluation technique using a magnetic single-yoke probe. Firstly, we evaluated hysteresis curves and impedance related to permeability of the material measured by a single-yoke probe, when an air gap length between the probe and specimens changes. The hysteresis curve gradually inclines to the axis of the magneto-motive force and magneto-motive force at which the magnetic flux is 0 decreases with increasing the gap length. The effective permeability also decreases with increasing the gap thickness. The incremental of gap thickness increases the reluctance inside the magnetic circuit composed of the yoke, specimen and gap, which results in the reduction of flux applying to specimen.

Sign in / Sign up

Export Citation Format

Share Document