• 제목/요약/키워드: crack depth

검색결과 602건 처리시간 0.028초

콘크리트 균열 깊이와 이미지 특성정보간의 상관성 분석 (Correlation Analysis between Crack Depth of Concrete and Characteristics of Images)

  • 정서영;유정호
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2021년도 봄 학술논문 발표대회
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    • pp.162-163
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    • 2021
  • Currently, the depth of cracks is measured using ultrasonic detectors in maintenance practice. This method consists of measuring the depth of cracks by attaching ultrasonic depth measuring equipment to the concrete surface, and there are restrictions on the timing and location of the inspection. These limitations can be addressed through the development of image-based crack depth measurement AI technology. If crack depth measurements are made based on images, restrictions on the timing and location of inspections can be lifted because images acquired with simple filming equipment can be used as input information. To efficiently develop these artificial intelligence technologies, it is essential to identify the interrelationship between crack depth measurements and image characteristic information. Thus, this study is a basic study of the development of image-based crack depth measurement AI technology and aims to identify image characteristic information related to crack depth.

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초음파를 이용한 콘크리트 시편의 피복두께 이하에 위치한 균열깊이 탐사 (Measurement of Crack Depth Located under Steel Reinforcement in Reinforced Concrete Specimens using Ultrasonic Method)

  • 임홍철;김연수;우상균;송영철
    • 한국구조물진단유지관리공학회 논문집
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    • 제6권4호
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    • pp.181-188
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    • 2002
  • The objective of this study is to determine crack depth located under steel reinforcement in concrete specimens using ultrasonic method. Experimental studies were performed on concrete specimens containing vertical and inclined surface-opening cracks with known depths. The other studies were carried out on specimens with flexural crack. Experimental results have shown that the crack depth is effectually measured when the distance between the probes is less than the crack depth. The effect of steel on crack depth estimation is studied through a model by considering P-waves diffaction at the tip of crack and steel. In addition, experimental results show that the ultrasonic method is one of useful methods to evaluate the crack depth in reinforced concrete.

차원 축소된 표면파 투과 함수와 인공신경망을 이용한 콘크리트의 균열 깊이 평가 기법 (Dimensionality Reduced Wave Transmission Function and Neural Networks for Crack Depth Estimation in Concrete)

  • 신성우;윤정방
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2007년도 정기 학술대회 논문집
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    • pp.27-32
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    • 2007
  • Determination of crack depth in filed using the self-calibrating surface wave transmission measurement and the cutting frequency in the transmission function (TRF) is very difficult due to variations of the measurement conditions. In this study, it is proposed to use the measured full TRF as a feature for crack depth assessment. A principal component analysis (PCA) is employed to generate a basis of the measured TRFs for various crack cases. The measured TRFs are represented by their projections onto the most significant principal components. Then artificial neural networks (NNs) using the PCA-compressed TRFs is applied to assess the crack in concrete. Experimental study is carried out for five different crack cases to investigate the effectiveness of the proposed method. Results reveal that the proposed method can be effectively used for the crack depth assessment of concrete structures.

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연속철근 콘크리트 슬래브 시스템의 균열진전 깊이와 균열폭 거동 관계 분석 (Relationship between Crack Propagation Depth and Crack Width Movement in Continuously Reinforced Concrete Slab Systems)

  • 조영교;김성민;오한진;최린;석종환
    • 한국도로학회논문집
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    • 제17권1호
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    • pp.83-90
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    • 2015
  • PURPOSES : The purpose of this study is to investigate the relationship between the crack propagation depth through a slab and crack width movement in continuously reinforced concrete slab systems (CRCSs). METHODS : The crack width movements in continuously reinforced concrete pavement (CRCP) and continuously reinforced concrete railway track (CRCT) were measured in the field for different crack spacings. In addition, the crack width movements in both CRCP and CRCT were simulated using finite element models of CRCP and CRCT. The crack width movements, depending on the unit temperature change, were obtained from both the field tests and numerical analysis models. RESULTS : The experimental analysis results show that the magnitudes of the crack width movements in CRCSs were related to not only the crack spacing, but also the crack propagation depth. In CRCP, the magnitudes of the crack width movements were more closely related to the crack propagation depths. In CRCT, the crack width movements were similar for different cracks since most were through cracks. If the numerical analysis was performed to predict the crack width movements by assuming that the crack propagates completely through the slab depth, the predicted crack width movements were similar to the actual ones in CRCT, but those may be overestimated in CRCP. CONCLUSIONS : The magnitudes of the crack width movements in CRCSs were mainly affected by the crack propagation depths through the slabs.

초음파 속도를 이용한 콘크리트의 균열깊이 측정 (Test for Concrete Crack Depth Measurement Using Ultrasonic Pulsevelocity Technique)

  • 이장화;김성욱;송영철
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1991년도 봄 학술발표회 논문집
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    • pp.117-120
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    • 1991
  • Cracks of concrete structure must be analyzed and estimated synthetically in order to have a maintenance and to insure the safety and the durability of structure. Concrete cracks have to be surveyed with respect to depth, width, shape and direction etc, but crack depth among these items is not measured easily. Occasionally, it needs to measure the crack depth of concrete structure for the purpose of evaulating the safe capacity and the necessity of repair. Therefore, this research is performed to verify the applicability and the accuracy of Ultra-sonic Pulse Velocity Technique(Tester), in non-destructive testing methods of concrete crack depth.

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대칭위치에 존재하는 미소원공결함의 깊이변화가 SM20C의 피로균열거동에 미치는 영향 (The Effect of Fatigue Crack Behavior on the Variable Depth of Micro Hole Defects in SM20C at the Symmetric Position)

  • 송삼홍;김성태
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2002년도 춘계학술대회 논문집
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    • pp.856-860
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    • 2002
  • The main objective of this study is to consider the effect of fatigue crack behavior on the variable depth of micro hole defects in SM20C at the symmetric position. The fatigue crack propagation test is performed by rotary bending fatigue test machine. The relationship between crack length(2a), cycles(N) and crack growth rate(da/dN) are investigated in this study. The result from the rotary bending fatigue test under the applied stress at 250MPa turned out that the fatigue life illustrated almost constant when the depth of symmetric micro hole deflects is both part A and B at the hope depth(h) = 0.5mm.

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Crack Detection, Localization and Estimation of the Depth In a Turbo Rotor

  • Park, Rai-Wung
    • Journal of Mechanical Science and Technology
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    • 제14권7호
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    • pp.722-729
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    • 2000
  • The goal of this paper is to describe an advanced method of a crack detection: a new way to localize position and to estimate depth of a crack on rotating shaft. As a first step, the shaft is physically modelled with a finite element method and the dynamic mathematical model is derived using the Hamilton principle; thus, the system is represented by various subsystems. The equations of motion of the shaft with a crack are established by adapting the local stiffness change through breathing and gaping from the crack to an undamaged shaft. This is the reference system for the given system. Based on a model for transient behavior induced from vibration measured at the bearings, a nonlinear state observer is designed to detect cracks on the shaft. This is the elementary NL-observer (Beo). Using the observer, an Estimator (Observer Bank) is established and arranged at the certain position on the shaft. When a crack position is localized, the procedure for estimating of the depth is engaged.

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SLAM 영상을 이용한 크랙 깊이 측정 (The Measurement of the Depth of Crack using Images of SLAM)

  • 황기환;전계석
    • 한국음향학회지
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    • 제16권3호
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    • pp.51-56
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    • 1997
  • 본 논문에서는 SLAM(Scanning Laser Acoustic Microscope) 시스템을 이용하여 고체 내부에 발생한 크랙의 깊이를 측정하는 방법을 연구하였다. SLAM 시스템은 초음파의 투과계수에 따른 그림자 영상을 재생시키므로 크랙 깊이에 대한 정확한 측정방법이 요구된다. 이를 위하여 시료에 초음파를 사각으로 입사시켜 얻은 SLAM 영상의 그림자영역과 시료내의 초음파 모드 변환에 대한 기하학적 구조를 이용하여 크랙의 깊이를 측정할 수 있는 방법을 제안하고 실험을 통하여 확인하였다. 실험을 위하여 알루미늄에 서로 다른 깊이로 수직형 라인-크랙의 결함을 갖는 시료를 가공하였고 시료에 초음파를 사각 입사시키기 위하여 20$^{\circ}$ 각도로 웨지를 제작하였다. 실험 결과, 크랙의 깊이가 증가할수록 SLAM 영상의 그림자 영역이 비례적으로 증가함을 보였고, 결함의 깊이에 대한 측정치와 실제치를 비교한 결과 약 6% 이하의 측정오차를 보였다.

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균열 형상비 변화에 따른 단일표면파로균열의 성장특성과 수명예측 (Growth Characteristics and Life Prediction of Single Surface Fatigue Crack with the Variation of crack Configuration Ratios)

  • 서창민;서덕영;정정수
    • 한국해양공학회지
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    • 제7권2호
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    • pp.173-181
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    • 1993
  • This work has been investigated the ralationship between single surface crack length and crack depth have influence on the fatigue life. The simulation based on experimental results of 2.25 Cr-1Mo steel at various crack configuration ratios has enabled successful prediction of fatigue life at room temperature. The effect of crack depth should be considered for predicting fatigue crack growth rates as well as that of surface crack length. It is also shwn that the crack growth mechanisms are in good agreement with expreimental data according to the interaction of crack length and crack depth.

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초음파에 의한 콘크리트의 균열깊이 측정에 있어서 음파모드에 관한 연구 (A Study on the Wave Modes in Measurements of the Crack Depth of Concrete by Ultrasonic Waves)

  • 한응교;어세형;김재열
    • 비파괴검사학회지
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    • 제9권1호
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    • pp.39-47
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    • 1989
  • As the necessity of the safety diagnosis of the concrete structure, more reliable ultrasonic technique to qualify the concrete is required. In this study, the artificial surface crack depth is measured using several types of the ultrasonic probes. As results, the horizontal shear wave probe is most useful to determine the crack depth compared to the other probes. For the surface wave probe, the ultrasonic wave path is changed with the surface crack depth.

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