• 제목/요약/키워드: non-destructive method

검색결과 749건 처리시간 0.028초

물리탐사법을 이용한 콘크리트 구조물 조사에 관한 연구 (Investigation of Concrete Structure Using Geophysical Prospecting Method)

  • 서백수;김용인
    • 산업기술연구
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    • 제23권A호
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    • pp.63-68
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    • 2003
  • Non-destructive method by tomography for safety diagnosis of civil engineering and building structures is tried. There are traveltime tomography that uses traveltime and fullwave tomography that uses the initial shock and seismic amplitude. But these methods have difficulty and weak points in accuracy and selection of initial value. In this study, corrected inversion method which is able to solve the two difficulty and this method is applied to theoretical pier model to calculate tomography.

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Field Inspection of Phase-Array Ultrasonic for PolyEthylene Electrofusion Joints

  • Kil, Seong-Hee;Jo, Young-Do;Yoon, Kee-Bong
    • 한국가스학회지
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    • 제16권1호
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    • pp.22-25
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    • 2012
  • Welding and/or fusion in polyethylene(PE) system made on site is focused on the control of the welding or fusion process to follow proper procedure. The process control is important, but it is not sufficient for the long term reliability of a pipe system. To achieve the rate of failure close to zero, Non Destructive Testing(NDT) is necessary in addition to joining process control. For electrofusion joints several non-destructive testing methods are available. The ultrasonic phased array technique is possible to detect various defects including wire deviations and regions with lack of fusion. In this studies, testing was carried to detect the defect after electrofusion joining of polyethylene piping is utilized by the ultrasonic phased array technique. From testing data, ultrasonic phased array technique is recommended as a reliable non-destructive testing method.

비파괴 시험방법을 이용한 원목 내부결함 예측 및 분류의 계량화(計量化)에 관한 연구 (I) - 원목의 횡단방향을 중심으로 - (Study on Mensurability of Internal Defect Prediction and of Classification of Log by NDE(Non-Destructive Evaluation) (I) - Focused on Cross Direction of Log -)

  • 박헌;강은창;전성진;윤경섭
    • Journal of the Korean Wood Science and Technology
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    • 제23권2호
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    • pp.47-54
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    • 1995
  • This study was to measure the properties of logs and classify them by non-destructive methods. The purpose of this experiment was focused at mensurability of logs by non-destructive methods. The non-destructive instrument, Stress-Wave Timer 239A which was made by Metriguard in U.S.A., was used. The stress wave velocities of log's cross direction were measured and compared with three different methods; 1. with hammer, 2. with hammer and D.B.H. meter, 3. with manufactured instrument. Number of used logs were seven logs, which were classified by naked eye into six groups; very severe rot, severe rot, mild rot & knot, mild rot & check, mild rot, sound log, and in diameter were into three groups; large(57.4cm), medium(36~41.2cm), small(28.9cm) log. The results, which were classified by mensurability with non-destructive methods, were followed; 1. The stress wave velocities were very different between rot and sound log. So it meant the possibility of mensurability of logs by non-destructive method even if high standard error. 2. The stress wave velocities decreased with checks more than with rots, which meant the checks affected speeds more. 3. The stress wave velocities increased with knot. 4. The velocities with manufactured instrument showed lower standard error, so more accurate results than other methods. Especially the required labour decreased from 3~4 to 2 persons. 5. Finally, the mensurability showed more accurate results and made the classification of logs scientific.

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Visualization of Tooth for Non-Destructive Evaluation from CT Images

  • Gao, Hui;Chae, Oksam
    • 비파괴검사학회지
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    • 제29권3호
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    • pp.207-213
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    • 2009
  • This paper reports an effort to develop 3D tooth visualization system from CT sequence images as a part of the non-destructive evaluation suitable for the simulation of endodontics, orthodontics and other dental treatments. We focus on the segmentation and visualization for the individual tooth. In dental CT images teeth are touching the adjacent teeth or surrounded by the alveolar bones with similar intensity. We propose an improved level set method with shape prior to separate a tooth from other teeth as well as the alveolar bones. Reconstructed 3D model of individual tooth based on the segmentation results indicates that our technique is a very conducive tool for tooth visualization, evaluation and diagnosis. Some comparative visualization results validate the non-destructive function of our method.

광선추적법을 이용한 비파괴 내부 결함 모델 및 해석 (Modeling and Analysis of a Ray Tracing Method for Non-Destructive Testing for Internal Defects)

  • 김택구;김주한
    • 한국정밀공학회지
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    • 제32권1호
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    • pp.75-81
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    • 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.

균열 주입부의 비파괴 검사에 의한 주입효과 판정에 관한 연구 (Non-destructive Testing Methods to Evaluate the Effectiveness of Crack Repair Using Expoxy and Microcement)

  • 최홍식;이시우;이호범;송영철;방기성
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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    • pp.841-846
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    • 2002
  • Development on non-destructive testing methods were performed to evaluate the effectiveness of crack repair for test beams induced a crack. Cracked beams are repaired with expoxy and microcement, and then they are tested by two methods, the ultrasonic pulse velocity method and the transfer function method. It is proved that the ultrasonic pulse velocity method is very valid for the evaluation of the effectiveness on expoxy repair, and the transfer function method is very applicable to evaluate the effectiveness on microcement repair.

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비파괴시험 자료를 적용한 콘크리트 기준강도의 통계적 추정 (Statistical Estimation of Specified Concrete Strength by Applying Non-Destructive Test Data)

  • 백인열
    • 한국안전학회지
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    • 제30권1호
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    • pp.52-59
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    • 2015
  • The aim of the paper is to introduce the statistical definition of the specified compressive strength of the concrete to be used for safety evaluation of the existing structure in domestic practice and to present the practical method to obtain the specified strength by utilizing the non-destructive test data as well as the limited number of core test data. The statistical definition of the specified compressive strength of concrete in the design codes is reviewed and the consistent formulations to statistically estimate the specified strength for assessment are described. In order to prevent estimating an unrealistically small value of the specified strength due to limited number of data, it is proposed that the information from the non-destructive test data is combined to that of the minimum core test data. The the sample mean, standard deviation and total number of concrete test are obtained from combined test data. The proposed procedures are applied to an example test data composed of the artificial numerical values and the actual evaluation data collected from the bridge assessment reports. The calculation results show that the proposed statistical estimation procedures yield reasonable values of the specified strength for assessment by applying the non-destructive test data in addition to the limited number of core test data.

비파괴 충격파를 이용한 아스팔트 공시체의 수분민감도 평가 (Evaluation for Moisture Susceptibility of Asphalt Mixtures using Non-Destructive Impact Wave)

  • 장병관;김도완;문성호;장영선
    • 한국도로학회논문집
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    • 제15권3호
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    • pp.53-63
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    • 2013
  • PURPOSES : This study is to evaluate moisture susceptibility of asphalt mixtures by using non-destructive impact wave and to determine durability so as to decrease the gap between before and after freezing in the future. METHODS : Using non-destructive impact wave, this study is to determine the dynamic modulus of asphalt specimen. Furthermore, the results obtained from two experiment accelerometers are used for the dynamic modulus determination. The dynamic moduli of specimens are compared with those of the freezing-thawing specimens. RESULTS : Test results showed that the dynamic modulus before freezing and thawing environment loads at each temperature dropped about 3.7% after the environmental loads. Furthermore, correlation analysis indicates that transition of dynamic modulus at each point is about 89.59%. CONCLUSIONS: Evaluation of asphalt mixtures using non-destructive impact wave has excellent repeatability and simple equipment for the test. Consequently, the method in the study will be useful for evaluating the characteristics of a various asphalt mixtures.

비파괴 방법을 이용한 목재의 부후 탐지 (Wood decay Detection by Non-destructive Methods)

  • 손동원;이동흡
    • Journal of the Korean Wood Science and Technology
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    • 제32권4호
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    • pp.74-81
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    • 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.

구조물의 비접촉 비파괴 검사를 위한 레이저 초음파법 적용 (A Structure Non-Contact and Non-destructive Evaluation Using Laser-Ultrasonics Application)

  • 김재열;송경석;양동조;김유홍
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2005년도 춘계학술대회 논문집
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    • pp.71-76
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    • 2005
  • The defects evaluation of the interior and the surface would be considered as vital characteristics in predicting the total life span of the steel structure. More importantly, the understandings in the interior composite of welding zone and the notifications in the presence, the formation, and the positioning of the non-metallic inclusion are necessary as well, since there were signs of relatively high defect frequency presented in the welding zone. The ultrasonic testing is a highly recommended technique chosen from among other techniques because of variety of advantages in conducting the non-destructive testing for the welding zone. However, the ultrasonic testing had technical disadvantages referred as followings; the problems due to the couplant between the PZT and the specimen, the formations that were miniature and complex, the moving subject, and the high temperature surrounding the specimen. This research was conducted to resolve the technical disadvantages of the contact ultrasonic testing by studying the non-contact ultrasonic testing where the ultrasonic waves were transferred by the laser, and revealing the specimen defects at its interior part and its surface part. The ultimate goal of this research was to develop a non-destructive evaluation applying the laser manipulated ultrasonic method for the steel structure.

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