• 한국신뢰성학회지:신뢰성응용연구
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• 제17권3호
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• pp.224-235
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• 2017

Purpose: Reliability is the most important factor to detect defects as wind turbines are deployed in large blades. The methods of detecting defects are various, such as non-destructive inspection and thermal imaging inspection. We propose the phased array ultrasonic testing method of non-destructive testing. Methods: We propose the active pressure mechanism for wind power blade. The phase array ultrasonic inspection method is used for fault detection inner blade surface. Controlled pressure of mechanism with respect to z-axis is important for guarantee the result of phase array ultrasonic inspection. The model based control and proposed mechanism are utilized for overall system stability and effectiveness of system. Result: The result of proposed pressure mechanism B is more stable than A. Convergence speed is also faster than A. Conclusion: We confirmed the performance of the proposed constant pressure mechanism through experiments. Non-destructive testing was applied to the specimen to confirm the reliability of detecting defects.

• 한국구조물진단유지관리공학회 논문집
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• 제3권1호
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• pp.129-136
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• 1999

In this paper, the new non-destructive equation will be proposed and evaluated in comparison to the other foreign's non-destructive equation. Through the comparisons cores strength of mock structure with compressive strength obtained from new non-destructive equation ; rebound hammer, ultra-sonic pulse velocity and combined method, it will be analyzed about application of non-destructive equation. The results are following. The new non-destructive equations follow ; (1) $F_c=9.5R{\cdot}N+62.5$ (2) $F_c=243Vp-739$ (3) $F_c=8.1R_o+205.3V_p-802$ where, $F_c$ : Compressive Strength, $R_o$ : Rebound Number. $V_p$ : Ultra-Sonic Pulse Velocity Trough the result of mock structure test, the combined method is superior to rebound method and ultra-sonic pulse velocity method in the estimation of concrete strength. In order to apply the non-destructive equation of concrete strength to the structures, it is necessary that we should be made process study on the non-destructive equation for estimation of concrete strength in the range, time and strength of application under long-term.

• International Journal of Korean Welding Society
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• 제3권2호
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• pp.53-59
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• 2003

Visual inspection using laser vision sensor was proposed for fast and economic inspection and was verified experimentally. Welding is one of the most important manufacturing processes for automotive and electronics industries as well as heavy industries. The weld zone influences the reliability of the products. There are two kinds of weld inspection tests, destructive and non­destructive test. Even though the destructive test is much more reliable, the product should be destroyed, and hence the non­destructive test such as ultrasonic or X­ray test was used to overcome this problem. However, these tests are not used for real time inspection.

• 한국방재안전학회논문집
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• 제15권4호
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• pp.11-20
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• 2022

국내의 앵커볼트 일반 비파괴 검사법은 육안검사와 타음검사를 적용하고 있으나, 육안검사는 기초에 포함된 부분이나 너트 및 베이스 플레이트가 설치된 부분에서 앵커볼트의 부식이나 피로균열 등을 확인하는 것이 어렵다. 타음검사는 주변 환경과 개인차에 의한 영향을 받기 때문에 객관적인 조사가 어려운 것이 현실이므로 이러한 결함을 정량적으로 추정할 수 있는 비파괴 검사 기술개발이 필요하다. 국내 도로시설물 앵커볼트의 점검은 육안조사를 수행하고 있으며, 교량받침, 낙교방지시설 등의 앵커볼트 중요도가 높으므로 기존 점검방법과 함께 비파괴검사 기술을 개발하여 앵커볼트의 예방정비를 통해 교량 수명연장에 기여할 필요가 있다. 본 기술 개발을 통해 현재 수행하고 있지 않은 앵커볼트의 비파괴검사를 수행함으로 도로시설물 앵커볼트의 선제적/능동적 유지관리가 가능한 기술로 연구개발 및 실용화가 시급하다. 본 논문에서는 비파괴 검사 기법 중 초음파탐상법(Ultrasonic test)을 적용하여 부식, 균열 등 앵커볼트의 결함 검출 가능성 및 실뢰도를 실험적으로 검증하였다. 기술 개발이 완성되면 검사 신뢰성 향상 원천기술 확보로 앵커볼트에 대한 선제적/능동적 유지관리의 실현이 가능할 것으로 기대된다.

• 품질경영학회지
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• 제8권2호
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• pp.15-22
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• 1980

This paper deals with the problem of determining a minimum cost sampling inspection plan for a single destructive testing by attribute. The cost for inspection lot is constructed by following three cost factors: (1) cost of inspection, (2) cost of accepted defective, (3) cost of rejected lot Using Hald's Bayesian approach in a single non-destructive testing, procedure's for finding the minimum cost single destructive sampling inspection plan by attribute are given. Assuming the uniform distribution as a prior-distribution and using numerical analysis by computer, a minimum cost single destructive sampling inspection plan by attribute for several lot sizes, unit cost, destructive testing cost, and salvage cost is given.

• 터널과지하공간
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• 제7권4호
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• pp.274-283
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• 1997

It is necessary to estimate the soundness of tunnel using non-destructive tests(NDT) for effective repairs and maintenances. But, the state of tunnel lining could not be investigated using previous non-destructive techniques, due to the various types of support and accessibility only from one side in tunnel lining. Recently, the various non-destructive techniques such as ground penetrating radar(GPR) have been researched and developed for inspection of tunnel lining. In this study, the usefulness and applicability of GPR test in tunnel lining inspection has been investigated through model tests and tunnel site application. This paper described the tunnel lining inspection for lining thickness, cavity and support using GPR test. From the results of tests, we have concluded that GPR test are very useful and effective techniques to look into the interior of lining and measure the lining thickness.

• 터널과지하공간
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• 제7권3호
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• pp.230-237
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• 1997

As concrete structure is getting old and decrepit, its inspection and diagnosis is getting important. Therefore, it is necessary to estimate the soundness of structure using non-destructive tests for effective repairs and maintenances. But, applications of non-destructive tests in tunnel have been used restrictively, due to accessibility only from one side in tunnel lining and presence of tunnel installations. Recently, the various non-destructive techniques have been studied. Especially, ground penetrating radar(GPR) and impact echo (IE) methods have been researched for tunnel inspection. In this study, the applicability of impact echo test in tunnel lining inspection has been investigated. This paper described the tunnel inspection for lining thickness and internal flaw using impact echo tests. Model tests were carried out using impact echo test systems on two concrete models, Model I is measuring for lining thickness, Model II is detecting for internal flaw. Also, the test were applied for lining inspections in a tunnel constructed by NATM. From the results of impact echo tests, we have concluded that impact echo test is a very useful and effective technique for inspecting the concrete tunnel linings.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.118-120
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• 2004

The non-destructive examinations for Yonggwang unit 6 was conducted in four different fields, these are 1)all non-destructive inspections for components, piping weldments and structures, 2)automated ultrasonic inspection for pressure vessels weldments. As the results, there were no big indications, and all indications detected during inspection were evaluated as the metallurgical and geometrical non-reinvent indications form weldments. Especially for the weldment of pipes, PD(Performance Demonstration) was applied as a UT inspection method according to 1995 edition of ASME code Sex. XI, this resulted in improvement of the reliability of UT inspection.

• 항공우주기술
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• 제6권1호
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• pp.230-236
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• 2007

항공기용 복합재 구조물의 제작에 대한 품질관리는 자재의 입고에서부터 제품의 제작과정에 이르는 모든 단계에서의 검사, 시험 및 모니터링을 포함한다. 이러한 품질관리 활동은 설계의 목적에 적합하게 이루어졌는지 확인하기 위한 것이다. 품질에 영향을 미치는 인자들은 자재, 입고검사, 보관 및 시효관리, 작업환경의 관리, 시험, 검사 및 기록의 관리 등이 있다. 본 연구에서는 항공기 복합재 구조물에서 파괴시험을 통한 공정의 적합성 입증방법과 품질관리방법을 고찰하였으며 이를 바탕으로 복잡한 복합재 구조물에 대한 비파괴검사 방법의 신뢰성을 확보하고 복합재의 설계요구조건을 확인할 수 있는 기법을 제시하였다.

• 한국정밀공학회지
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• 제31권9호
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• pp.777-782
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• 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.