An algorithm for the characterization of surface crack by use of dipole model and magneto-optical non-destructive inspection system

2000 ◽  
Vol 14 (10) ◽  
pp. 1072-1080 ◽  
Author(s):  
Jinyi Lee ◽  
Sungki Lyu ◽  
Younghyun Nam
2012 ◽  
Vol 166-169 ◽  
pp. 1931-1934
Author(s):  
Shiuh Chuan Her ◽  
Sheng Tung Lin

Surface cracks are the most common defects in structures. Ultrasonic has been widely used as a non-destructive evaluation technology in the case of crack characterization. In this investigation, surface waves are applied to a steel block with artificial slots to characterize the crack depth. A series of test specimen with different depths of surface crack ranging from 4mm to 10mm was fabricated. The depth of the surface crack was evaluated using the pitch-catch ultrasonic technology. In this work, 2.25 MHz, 5 MHz and 10 MHz of incident waves were employed to investigate the effect of frequency on the crack depth detection. Experimental test results show that the accuracy of crack depth detection is increasing with the increase of frequency.


2014 ◽  
Vol 1061-1062 ◽  
pp. 874-880
Author(s):  
Lei Jiang ◽  
Zhi Ping Liu ◽  
Xing Le Liu ◽  
Ge Lu

Eddy current thermography is an emerging non-destructive method for detection and characterization of surface cracks in conductive specimen over a relatively large area. In this paper, the weld crack testing method based on eddy current thermography was proved to be feasible through studying the influence of inductor orientation, excitation frequency and crack length, depth, width on the surface temperature distribution using finite element analysis software COMSOL Multiphysics4.3b. The findings show that the quantitative evaluation is more viable according to the optimized parameters. This method has a certain reference value for quantitative analysis and designing inspection system with eddy current stimulated approach.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Prashanth Gopalan ◽  
Yunshan Wang ◽  
Berardi Sensale-Rodriguez

AbstractWhile terahertz spectroscopy can provide valuable information regarding the charge transport properties in semiconductors, its application for the characterization of low-conductive two-dimensional layers, i.e., σs <  < 1 mS, remains elusive. This is primarily due to the low sensitivity of direct transmission measurements to such small sheet conductivity levels. In this work, we discuss harnessing the extraordinary optical transmission through gratings consisting of metallic stripes to characterize such low-conductive two-dimensional layers. We analyze the geometric tradeoffs in these structures and provide physical insights, ultimately leading to general design guidelines for experiments enabling non-contact, non-destructive, highly sensitive characterization of such layers.


Sign in / Sign up

Export Citation Format

Share Document