• 자동차안전학회지
• /
• 제13권2호
• /
• pp.50-56
• /
• 2021

The purpose of this study is to investigate vulnerable parts of tower crane structures by analyzing extensive non-destructive test data. Approximately ten percent of domestically registered tower cranes were inspected by using magnetic particle inspection. The testing was carried out as advised in KS B 0213. The non-destructive results was analyzed with respect to jib types, age and crane size. As a result, the number of crack occurrences were the largest in mast parts, followed by main jib part. Moreover, it was found that turntables were important parts deserved to be noticed at the perspective of safe maintenance.

• 한국작물학회지
• /
• 제46권5호
• /
• pp.401-406
• /
• 2001

The applicability of non-destructive near infrared reflectance spectroscopic (NIRS) method was tested to determine the protein and oil contents of intact soybean [Glycine max (L.) Merr.] seeds. A total of 198 soybean calibration samples and 101 validation samples were used for NIRS equation development and validation, respectively. In the developed non-destructive NIRS equation for analysis of protein and oil contents, the most accurate equation was obtained at 2, 8, 6, 1(2nd derivative, 8 nm gap, 6 points smoothing, and 1 point second smoothing) and 2, 1, 20, 10 math treatment conditions with Standard Normal Variate and Detrend (SNVD) scatter correction method and entire spectrum (400-2500 nm) by using Modified Partial Least Squares (MPLS) regression, respectively. Validation of these non-destructive NIRS equations showed very low bias (protein: 0.060%, oil: -0.017%) and standard error of prediction (SEP, protein: 0.568 %, oil : 0.451 %) as well as high coefficient of determination ($R^2$, protein: 0.927, oil: 0.906). Therefore, these non-destructive NIRS equations can be applicable and reliable for determination of protein and oil content of intact soybean seeds, and non-destructive NIRS method could be used as a mass screening technique for selection of high protein and oil soybean in breeding programs.

• 한국정밀공학회지
• /
• 제31권9호
• /
• pp.777-782
• /
• 2014

Usually, railway axles are designed for infinite life based on endurance limit of the material and the axle is not fractured immediately when a surface crack initiated. The railway axles have been inspected regularly by NDT such as ultrasonic testing, magnetic testing and eddy current testing and so on. Because the axle failure is profoundly influenced by the probability of missing a fatigue crack during an NDT inspection, it is necessary to evaluate the Non Destructive Interval of railway axle. In the present paper, the Non Destructive Interval of railway axle based on fracture mechanics and finite element analysis was investigated. It was shown that the Non Destructive Interval of railway axle can be evaluated using fracture mechanics approach and extended using NDT which a crack can detect clearly.

• Journal of the Korean Wood Science and Technology
• /
• 제32권4호
• /
• pp.74-81
• /
• 2004

비파괴 시험 방법 중 초음파 방법을 이용하여, 목재의 열화상태를 진단하였다. 기초 자료로서, 목재 내 온도변화에 따른 초음파 전송속도의 변화, 목재 내 함수율변화에 따른 초음파 전송속도 변화, 목재 강제부후에 의한 중량감소와 초음파 전송속도 변화를 검토하였다. 또한 원목의 비파괴 시험 등을 수행하고, 초음파 전송속도에 근거한 부후분포도를 작성하여 고목재의 열화 진단을 하였다. 일련의 시험들을 통하여 비파괴 방법에 의한 목재 열화진단을 위한 데이터를 축적하고, 이를 고목재에 적용하여 목재 내부의 부후분포도를 작성함으로써 금후 고목재의 비파괴 방법에 의한 부후탐지의 가능성을 검토하였다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
• /
• pp.933-936
• /
• 2006

Many non-destructive inspection methods have recently been developed for concrete structures. However, these methods can obtain only physical information of concrete, such as crack depth, delamination or position of reinforcement etc. near its surface. If chemical information is required, sampling and componential analyses may be earned out. Non-destructive method that can detect deterioration factors such as carbonation, chloride content or sulfate attack would be an outstanding innovation in inspection methodologies. In this research, near-infrared spectroscopy and X-ray fluorescence analysis were applied for componential analysis for concrete. These methods are very effective compared to traditional methods, therefore, working efficiency and maintenance cost will be improved.

• Composites Research
• /
• 제17권1호
• /
• pp.1-9
• /
• 2004

본 연구에서는 타격음을 이용한 비파괴 검사법을 제안하였다. 제안된 방법(tapping sound analysis)은 건강한 구조물과 손상된 구조물의 타격음의 차이를 분석하여 구조물의 손상 유무를 판단하는 방법이다. 타격음의 직접적인 비교는 비효율적이므로 타격음으로부터 특성을 추출하기 위해 wavelet packet transform에 기반한 특성추출법을 제안하였다. 또한 추출된 특성 자료를 바탕으로 손상의 유무를 판단하는 지표로서 특성 지수를 정의하였다. 제안된 방법의 타당성을 밝히기 위해 실험적인 검증을 수행하였다. 복합재료를 이용하여 건강한 구조물과 손상된 구조물을 제작하고 타격음을 측정하였다. 제안된 손상 판단 기법을 이용한 결과로부터 특성 지수에 의한 손상 판단의 타당성을 밝혔다.

• 한국정밀공학회지
• /
• 제32권1호
• /
• pp.75-81
• /
• 2015

Modeling and analysis using a ray tracing method for internal defects were described. Reflection and refraction of rays on the interface of defects were modeled using the Harvey model and the Lambertian model. The diffraction on the interface of defects affected the incoming signals and it could evaluate any defects in the matter and its signal would be analyzed with the ray tracing simulation. The simulation results were compared with actual detecting signals and the ray tracing model was shown in good agreement with experimental data. This method has a possibility to be used as wave propagation modeling in non-destructive testing.

• Journal of Welding and Joining
• /
• 제17권6호
• /
• pp.100-107
• /
• 1999

In this paper, we deal with the speckle noise reduction and parameter estimation of ultrasonic NDT(non-destructive test) signals obtained during weld inspection of piping. The overall approach consists of three major steps, namely, speckle noise analysis, proposition of wavelet domain AR(autoregressive) model and flaw detection by proposed model parameter. The data are first processed whereby signals obtained using vertical and angle beam transducer. Correlation properties of speckle noise are then analyzed using multiresolution analysis in wavelet domain. The parameter estimation curve obtained using the proposed model is classified a flaw in weld region where is contaminated by severe speckle noise and also clear flaw signal is obtained through CA-CFAR threshold estimator that is a nonlinear post-processing method for removing the noise from reconstructed ultrasonic signal.

• 비파괴검사학회지
• /
• 제30권3호
• /
• pp.257-260
• /
• 2010

Advancements in the imaging and computing technology have opened the path to digital holography for non-destructive investigations of technical samples, material property measurement, vibration analysis, flow visualization and stress analysis in aerospace industry which has widened the application of digital holography in the above fields. In this paper, we demonstrate the non-destructive investigation and micro-structure measurement application of digital holography to the small particles and a biological sample. This paper gives a brief description of the digital holograms recorded with this system and illustratively demonstrated.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2018년도 추계학술대회
• /
• pp.71-71
• /
• 2018