• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.1
• /
• pp.44-51
• /
• 2005

Material degradation is a multibillion-dollar problem which affects all the industries amongst others. The last decades have seen the development of newer and more effective techniques such as Focused-ion beam(FIB), Transmission electron microscopy(TEM), Secondary-ion mass spectroscopy(SIMS), auger electron spectroscopy(AES), X-ray Photoelectron spectroscopy(XPS) , Electrochemical impedance spectroscopy(EIS), Photo- stimulated luminescence spectroscopy(PSLS), etc. to study various forms of material degradation. These techniques are now used routinely to obtain information on the chemical state, depth profiling, composition, stress state, etc. to understand the degradation behavior. This paper describes the use of these techniques specifically applied to materials degradation and failure analysis.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2003.04a
• /
• pp.504-512
• /
• 2003

Simulation programs have been developed and used as an attempt to improve the accuracy of Non-Destructive Evaluation(NDE) techniques. The applicability of these programs is very limited, however, because it is difficult to describe the delicacy of the propagation of stress waves. To investigate the applicability of the finite element analysis for stress wave-based NDE techniques numerical simulation for Impact-Echo method and SASW method is performed. The numerical studies are performed to determine the essential parameters such as contact time of impact load, mesh size and time step size. These studies show that the choice of parameter is very important for improving the accuracy and confidence of the numerical procedure and, thereby, the applicability of the numerical analysis for stress wave-based NDE techniques

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.2
• /
• pp.163-168
• /
• 1989

In this paper, Rayleigh wave velocity has been measured by detecting the backscattered signal generating near the Rayleigh critical angle in the elastic medium. The rotating system has been made for the measurment of Rayleigh angle. It has been shown that the measured velocity for the stainless steel, brass aluminum, copper has been good agreement with the theoretical value. The method of non-destructive evaluation using backscattering signal has been presented and the c-scan acoustic image for internal of IC sample has been displayed.

• Proceedings of the Optical Society of Korea Conference
• /
• 2000.08a
• /
• pp.52-53
• /
• 2000

물질 내부에서의 초음파(ultrasonics)의 전파특성을 분석하면 측정대상의 외형적 크기와 성분조성, 내부결함의 분포, 그리고 결정입경(grain size) 등과 같은 물질의 미세조직을 비파괴적으로 평가(NDE; non-destructive evaluation)할 수 있다. 초음파를 이용하는 비파괴 평가에 있어서 기존에는 주로 접촉식 압전변환기(PZT transducer)를 이용하여 초음파를 인가함과 동시에 이를 이용하여 측정대상 내부를 전파한 초음파를 검지하는 방식을 이용하여 왔다. 이와 같은 압전변환기를 이용한 비파괴 평가는 측정방법이 비교적 간단하고 초음파 에너지의 정량화가 용이한 장점이 있으나 측정방식이 접촉식이기 때문에 측정 시편이 고온이거나 움직이는 대상에는 적용이 어렵다. 따라서 비파괴 평가의 궁극적인 활용목표의 하나인 온-라인 평가를 실현하기 위해서는 비접촉식 초음파 평가방법이 정립되어야 한다. 이러한 관점에서 최근 레이저를 이용한 비접촉식 초음파의 생성 및 검지방법에 대한 연구가 진행되고 있다. (중략)

• Proceedings of the KIEE Conference
• /
• 1988.07a
• /
• pp.47-50
• /
• 1988

In this paper, Rayleigh wave velocity has been measured by detecting the backscattered signal generating near the Rayleigh critical angle in the elastic medium. The rotating system has been made for the measurment of Rayleigh angle. It has been shown that the measured results has been good agreement with the theoretical value. The method of non-destructive evaluation using backscattering signal has been presented and the internal of IC sample has been displayed acoustic image with good contrast.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.25 no.2
• /
• pp.81-86
• /
• 2005

This paper proposes a non-destructive ESPI technique to quantitatively evaluate defects inside a semiconductor package. The inspection system consists of the ESPI system, a thermal loading system and an adiabatic chamber. The technique is high feasibility for non-destructive testing of a semiconductor and overcomes the weaknesses of previous techniques, such as time-consumption and difficult quantitative evaluation. Most defects are classified as delamination defects, resulting from the insufficient adhesive strength between layers and from non-homogeneous heat spread. Ninety percent of the tested samples had delamination defects which originated at the corner of the chip and nay be related to heat spread design.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1998.10a
• /
• pp.415-422
• /
• 1998

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.02a
• /
• pp.451-456
• /
• 2000

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2011.06a
• /
• pp.1345-1346
• /
• 2011

• Nuclear Engineering and Technology
• /
• v.52 no.4
• /
• pp.856-862
• /
• 2020

Defect inspection system for industrial applications takes the important portion. Non-destructive inspection method has been significantly improved. Infrared thermography, as one of method for non-destructive inspection, can provide relatively precise data and quick inspection time. This study, it was performed to measure defect according to the measurement limit of the non-visible areas such as the back surface of the pipe using reflection plate using reflection plate based on Infrared thermography. The materials of the reflection plate were determined in consideration of the space limitation and the thermal characteristics, and defects were detected by the manufactured reflection plate. Detection of defect in non-visible area using the candidate materials for reflection plate was conducted.