Non-destructive evaluation of nanoparticles dispersion in nanocomposite dielectrics based on nonlinear ultrasonic method

Author(s):  
W. Fang ◽  
H. Wang ◽  
L. Cheng ◽  
L. Yang ◽  
R. Liao
2005 ◽  
Vol 297-300 ◽  
pp. 813-818 ◽  
Author(s):  
Job Ha ◽  
Kyung Young Jhang

The linear ultrasonic technique has been extensively used as a powerful, non-destructive test tool for reliability testing and failure analysis of electronic packaging. This is used most often in the inspection of defects such as delaminations, voids, or cracks through use of a SAM (Scanning Acoustic Microscope). Then, as the reliability level that is required of electronic packaging becomes higher and the thickness of package becomes thinner, the possible defect which needs to be detected becomes smaller. In the conventional SAM, however it is very difficult to detect small defects less than m µ 1 . 0 , such as micro-delaminations. In order to solve such a problem, this paper proposes a nonlinear ultrasonic method, where the nonlinearity caused by the effect of crack-face interactions is considered. The basic concept of this method involves harmonic frequencies that are generated in the transmitted ultrasonic wave due to the partial contact at the interface of micro-delamination. As an evaluation index, the nonlinear parameter dependent on the amplitude of the second order harmonic frequency component is obtained by spectral analysis of the transmitted signal. Experimental results show that the nonlinear parameter has good correlation with the micro-gap and the proposed method can detect the micro-delamination even less than nm 1 .


2013 ◽  
Vol 26 (5) ◽  
pp. 545-552 ◽  
Author(s):  
Saju T. Abraham ◽  
S. K. Albert ◽  
C. R. Das ◽  
N. Parvathavarthini ◽  
B. Venkatraman ◽  
...  

2006 ◽  
Vol 321-323 ◽  
pp. 968-971
Author(s):  
Won Su Park ◽  
Sang Woo Choi ◽  
Joon Hyun Lee ◽  
Kyeong Cheol Seo ◽  
Joon Hyung Byun

For improving quality of a carbon fiber reinforced composite material (CFRP) by preventing defects such as delamination and void, it should be inspected in fabrication process. Novel non-contacting evaluation technique is required because the transducer should be contacted on the CFRP in conventional ultrasonic technique during the non-destructive evaluation and these conventional contact techniques can not be applied in a novel fiber placement system. For the non-destructive evaluation of delamination in CFRP, various methods for the generation and reception of laser-generated ultrasound are applied using piezoelectric transducer, air-coupled transducer, wavelet transform technique etc. The high frequency component of laser-generated guided wave received with piezoelectric sensor disappeared after propagating through delamination region. Air-coupled transducer was tried to be adopted in reception of laser-generated guided wave generated by using linear slit array in order to generate high frequency guided wave with a frequency of 1.1 MHz. Nevertheless, it was failed to receive high frequency guided wave in using air-coupled transducer and linear slit array. Transmitted laser-generated ultrasonic wave was received on back-wall and its frequency was analyzed to establish inspecting technique to detect delamination by non-contact ultrasonic method. In a frequency spectrum analysis, intensity ratio of low frequency and center frequency was approvable parameter to detect delamination.


2016 ◽  
Vol 17 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Hong Jae Yim ◽  
Sun-Jong Park ◽  
Jae Hong Kim ◽  
Hyo-Gyong Kwak

2019 ◽  
Vol 31 (3) ◽  
pp. 364-376 ◽  
Author(s):  
Nan Zhao ◽  
Linsheng Huo ◽  
Gangbing Song

A real-time nonlinear ultrasonic method based on vibro-acoustic modulation is applied to monitor early bolt looseness quantitatively by using piezoceramic transducers. In addition to the ability to detect the early bolt looseness, a major contribution is that we replaced the shaker, which is commonly used in a vibro-acoustic modulation method, by a permanently installed and low-cost lead zirconate titanate patch. In vibro-acoustic modulation, when stimulating two input waves with distinctive frequencies, namely the high-frequency probing wave and the low-frequency pumping wave, the high-frequency probing wave will be modulated by the low-frequency pumping wave to generate sidebands in terms of bolt looseness. Thus, the influence of low-frequency voltage amplitudes on the modulation results, which is ambiguous in previous research, is also analyzed in this article. The results of experiment demonstrated that the lead zirconate titanate–enabled vibro-acoustic modulation method is reliable and easy to implement to identify the bolt looseness continuously and quantitatively. In addition, low-frequency amplitudes of actuating voltage should be selected in a reasonable range. Finally, we compared the vibro-acoustic modulation method with the time-reversal method based on the linear ultrasonic theory, and the result illustrates that vibro-acoustic modulation method has better performance in monitoring the early bolt looseness.


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