• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.385-390
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• 2000

In this study, the Non-Destructive Testing Equipment was introduced for the compaction control and the evaluation of pavements properties and the developing process was showed. Falling Weight Deflectometer(FWD) is a system for performing non-destructive testing of pavement and the other foundation structures. The system develops forces from the acceleration caused by the arrest of a falling weight and these forces are transmitted onto the surface of a structure causing it to deflect much as it would due to the weight of a passing wheel load. The structure will bend downward and exhibit a deflection basin. FWD uses a set of velocity sensors to determine the amplitude and shape of the deflection basin. The deflection response, when related to the applied loading, can provide information about the strength and condition of the various elements of the test structure. In this study, a computer program was developed that can be used to evaluate pavement and foundation structures from the data produced by FWD. The Falling Weight Deflectometer, non-destructive testing equipment, is increasing used at the whole world.

• 비파괴검사학회지
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• 제7권2호
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• pp.52-57
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• 1988

This article presents a newly developed equipment system for computer-aided, magneto-inductive testing of metals for material properties. The advantages of ultramodern computer technology over conventional test mothods are illustrated, in particular the greatly simplified equipment adjustment and the extended possibilities of test data evaluation. The characterisitics of the new system of equipment are demonstrated by way of practical testing examples.

• Structural Monitoring and Maintenance
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• 제7권1호
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• pp.43-58
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• 2020

Pile foundations of existing bridges lie in soil and water environment for long term and endure relatively heavy vertical loads, thus prone to damages, especially after stricken by external forces, such as earthquake, collision, soil heap load and etc., and the piles may be injured to certain degrees as well. There is a relatively complete technical system for quality inspection of new bridge pile foundations without structures on the top. However, there is no mature technical standard in the engineering community for the non-destructive testing technology specific to the existing bridge pile foundations. The quality of bridge pile foundations has always been a major problem that plagues bridge maintenance. On the basis of many years' experiences in test engineering and theoretical studies, this study developed a new type of detection technology and equipment for the existing bridge piles.

• 터널과지하공간
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• 제7권1호
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• pp.75-83
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• 1997

The interest of diagnosis and maintenance of construction is increasing due to the collapse of infastructures. To obtain the complete, reliable and reproducible data ont he state of the entire structure, various non-destructive techniques are available, Especially, specific constructional characteristics of tunnels make the application of non-destructive tests more difficult. Despite of the complications of these conditions, non-destructive techniques should be capable of providing a description of the state of the tunnel lining, without the removal of the tunnel installations. In this paper, the infrared thermography technique using the difference of surface temperature was studied. The optimum equipment was selected and introduced, the principle, testing method and data anlaysis were investigated. Also, through the case study for inspection of concrete tunnel lining, this technique has proven to be a valuable non-destructive test for detecting the defects such as crack, leakage of water and exfoliation of concrete. The applicability and usefulness of this technique for estimation of concrete tunnel lining have been conformed.

• 한국해양공학회지
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• 제13권4호통권35호
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• pp.45-54
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• 1999

Non destructive test is applied to revise mechanical strength and assume material strength or defect of material, equipment and structure, instead of fracture test. Especially, ultrasonic test has the characteristics such as an excellent permeability high-sensitiveness to fine defect and an almost exact measurement for position, size and direction of inner defect which differ from other non destructive tests. In this study, the program is developed to evaluate optimal testing condition, to distinguish obstacle echo and defect position. This program on the basic of Ray-Tracing model shows generation and processing of ultrasonic pulse. The simulation is compared with testing in the 3 cases of an oblique angle transducer like $45^{\circ},\;60^{\circ}\;and\;70^{\circ}$. The test result for all conditions is well compared with simulation result when relative not is within $0.1{\sim}7.2%$. And the course of several echos is simply assumed through simulation.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.105-111
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• 2016

In order to inspect the quality of spot welding, inefficient destructive test and NDT (non destructive testing) utilizing expensive foreign ultrasonic inspection are being conducted in the automobile production lines, but NDT will be difficult to be used in the domestic automobile production due to complexity of the waveform analysis and lack of mobility. In this paper, NDT system inspecting the quality of spot welding based on mobile network is proposed to complement drawbacks of the conventional inefficient destructive testing and NDT inspecting the quality of spot welding. Regardless of daily condition of NDT tester, the proposed NDT system can determine the quality of spot welding automatically and transmit the information of NDT quality to smart devices of field workers in real-time so that convenience of NDT and productivity of automobile production will be improved. Several specimens with a variety of welding quality was produced to evaluate the performance of the proposed mobile ultrasonic NDT system and the conventional foreign equipment, through this experiments, the proposed mobile ultrasonic NDT system indicate the superior properties compared to the conventional equipment in terms of convenience, productivity, and economic.

• 한국건설안전학회 논문집
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• 제6권1호
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• pp.7-11
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• 2024

펌프카는 콘크리트를 타설하는 장소에 필요한 만큼 운반하는 장비로, 짧은 시간에 많은 양의 콘크리트 타설하기 위해서는 펌프카를 사용하는 것이 경제성 및 품질관리 측면에 가장 효율적이다. 그러나 최근에는 콘크리트 타설중에 붐 파손으로 인한 인명피해가 많이 발생하고 있으므로 본 연구에서는 장비 제작단계, 노후장비에 대한 검사기준, 장비대여제도 등의 개선이 필요함을 제언한다. 그 이유는 펌프카의 유한요소해석 결과, 붐 2단에서 작용하는 상당응력과 붐상단에서 최대응력이 895.39MPa로 나타났고, M.S. 0.04로 가장 낮게 평가되었으므로 보강의 필요성을 인식했다. 그리고 2단계 붐은 1~5단계 붐대 중 가장 스트레스가 많고, 취약한 부분임을 확인했다. 따라서 설계 및 제작 단계에서 부재의 두께와 강성을 높이고, 현재 사용되는 장비의 강판에 대한 보강이 필요하다. 또한, 일반 건설기계 전체에 대한 비파괴 검사를 의무적으로 반영하고, 비파괴검사 및 정기검사시 붐대 결함 누락에 대한 책임을 검사기관에 부담시키는 제도 구축이 시급하다.

• 한국방사선학회논문지
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• 제11권4호
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• pp.183-188
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• 2017

최근, 감마선 조사기의 자동 원격 조사 제어기가 오동작하여 방사선작업종사자가 방사선 피폭 사고가 지속적으로 보고되고 있다. 이에 NDT 분야에서는 방사선에 대한 잠재적 사고를 미연에 방지하기 위한 방사선원 모니터링 시스템 구축에 많은 시간과 재원을 투자하고 있다. 이에 본 연구에서는 다양한 비파괴검사장비에 범용적으로 적용할 수 있는 방사선원 위치 모니터링 시스템의 개발을 위한 선행연구로써 몬테카를로 시뮬레이션을 통해 산화납 기반 방사선 검출기에 대한 감마선 응답 특성을 모의 추정하였다. 연구 결과, 방사선 검출기의 최적화 두께는 방사선원에서 방사되는 감마선 에너지에 따라 상이하며 에너지가 증가함에 따라 최적화 두께가 점차 증가하는 것으로 나타났다. 결론적으로 PbO 기반 방사선 검출기의 최적화 두께는 Ir-192에 대하여 $200{\mu}m$, Se-75 $150{\mu}m$, Co-60 $300{\mu}m$로 분석되었다. 이러한 연구 결과를 바탕으로 범용적으로 적용하기 위하여 2차 전자 평형을 고려한 PbO 기반 방사선 검출기의 적절한 두께는 $300{\mu}m$로 평가되었다. 이러한 결과는 차후 다양한 NDT 장비에 범용적으로 적용하기 위한 방사선원 위치 모니터링 시스템을 개발 시 방사선 검출기에서 요구되는 적절한 두께를 결정하는데 있어 기초자료로 활용될 수 있을 것으로 사료된다.

• 한국안전학회지
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• 제10권4호
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• pp.9-12
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• 1995

Detection of small defects by medical ultrasonic testing when the thermal sprayed coating by $MoSi_2$ on the metal is done. The defects may occur at the bonded surface. So, the detecting method of the defects by non-destructive in spection is desired. Here, in order to examine the possibility of the detection of the small defects by the ultrasonic. The electronic scanning ultrasonic equipment using an array probe developed as the medical ultrasonic diagnostic equipment is applied for the detection of the metal material defects. It's validity is investigated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.126-128
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• 2001

In this paper, Magnetic Flux Leakage(MFL) method is used to detect surface defect in ferromagnetic plate. Surface defects are created on the SM 45C ferromagnetic plate and magnetizing equipment is composed to perform MFL nondestructive testing. The length and width of defect is twice the thickness of ferromagnetic plate, and defects with different depths are made artificially for the experiment. Also, NdFeB magnet in magnetizing equipment is used to make magnetic flux. This paper shows that it is possibile to detect 10% defect and to analyze numerically for any defect using MFL method.