• 한국전산구조공학회논문집
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• 제23권6호
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• pp.607-613
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• 2010

FRANC3D is a program for simulating arbitrary three-dimensional crack growth. Recently, a completely new version of the program, FRANC3D/NG, has been created. Unlike previous versions, which relied largely on boundary element analysis, the new version of the program works with finite element analysis exclusively and is designed to work with general-purpose commercial finite element packages. This paper presents the theoretical underpinnings of the procedures to adaptively modify the geometry and mesh of a model to simulate crack growth.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 추계학술대회 논문집
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• pp.140-145
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• 1998

In this study, analysis for fatigue crack propagation behavior of interface and aroud interface under rotary bending stress. Though K values are nearly the same in around interface by BEM 2-D, fatigue crack propagated H.A.Z. Around Interface crack propagation speed is m=0.678 in H.A.Z by Paris' law. In this case(friction welded materials: STS304, SM15C), fatigue crack growth is considered SM15C metal microstructure and elastic flow from this result. Result is more metal microstructute dependence than stress dependence by analysis (BEM 3-D, BEM 2-D) and fatigue crack propagation

• 한국구조물진단유지관리공학회 논문집
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• 제22권1호
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• pp.129-136
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• 2018

대형 용접 구조물에 대한 피로설계 수명의 예측은 일반적으로 Palmgren Miner과 등가손상도 방법 또는 선형누적손상도 방법을 사용한다. 또한 용접 구조물에서 피로 균열이 발생되면 잔존 수명은 S-N 곡선과 선형 파괴역학에 기초하여 예측되고 있다. 본 연구에서는 면외거셋 용접이음의 3차원 피로균열 진전거동과 피로수명을 예측하기 위하여 피로 시험을 실시하였다. 면외거셋 용접이음의 3차원 피로균열진전해석은 NX NASTRAN 및 FRANC3D를 이용하여 유한요소 해석을 실시하였다. 면외거셋 용접이음의 균열 형상비, 초기균열 크기 및 응력비에 미치는 영향을 검토하기 위하여 피로균열진전 해석을 실시하였다. 또한 초기균열크기, 균열 형상비와 응력비의 변화에 따른 3차원 피로균열진전 해석 결과와 피로시험결과를 비교하였다. 피로균열진전 해석결과, 피로균열 진전속도와 응력확대계수와의 관계에서 피로시험과 유사하게 나타남을 확인하였으며, 면외거셋 용접이음의 피로수명을 추정할 수 있음을 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1185-1186
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• 2013

• Structural Engineering and Mechanics
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• 제42권5호
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• pp.701-713
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• 2012

Results pertaining to 3D investigations on the effect of the thickness on the stress fields at the crack front are presented. A 3D finite element analysis is performed using a modified single edge-notched tension specimen configuration, with an inclined crack to include mixed mode I-II. A technique to mesh the crack front (3D) with singular finite elements in ANSYS without using third party software is introduced and used in this study. The effect of the specimen thickness is explicitly investigated for six thicknesses ranging from 1 to 32 mm. In addition, three crack inclination angles, including pure Mode-I, are used to study the effect of mixed-mode I-II fracture. An attempt is made to correlate the extent of a particular stress state along the crack front to thickness. In addition, ${\sigma}_{zz}/{\nu}({\sigma}_{xx}+{\sigma}_{yy})$ contours at the crack front are presented as a useful means to analyze the stress state.

• 한국도로학회논문집
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• 제18권1호
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• pp.73-83
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• 2016

PURPOSES : The purpose of this study is to develop a method for improving the accuracy of analysis results obtained from a two-dimensional (2-D) numerical analysis model of continuously reinforced concrete pavement (CRCP). METHODS : The analysis results from the 2-D numerical model of CRCP are compared with those from more rigorous three-dimensional (3-D) models of CRCP, and the relationships between the results are recognized. In addition, the numerical analysis results are compared with the results obtained from field experiments. By performing these comparisons, the calibration factors used for the 2-D CRCP model are determined. RESULTS : The results from the comparisons between 2-D and 3-D CRCP analyses show that with the 2-D CRCP model, concrete stresses can be overestimated significantly, and crack widths can either be underestimated or overestimated by a slight margin depending on the assumption of plane stress or plane strain. The behaviors of crack width in field measurements are comparable to those obtained from the numerical model of CRCP. CONCLUSIONS : The accuracy of analysis results from the 2-D CRCP model can be improved significantly by applying calibration factors obtained from comparisons with 3-D analyses and field experiments.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.72-79
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• 2000

In case of rough contact fatigue, the accurate calculation of surface tractions is essential to the prediction of crack initiation life. Accurate Surface tractions influencing shear stress amplitude can be obtained by contact analysis based on tile morphology of contact surfaces. In this study, to simulate rough contact under sliding condition, gaussian rough surface generated numerically in the previous study was used and to calculate crack initiation life in the substrate, dislocation pileup theory was used.

• Structural Engineering and Mechanics
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• 제12권4호
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• pp.377-396
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• 2001

The excessive cracking of RC cantilever decks, which often requires special attention for structural engineers, is studied using a three-dimensional crack analysis model. The model is based on a fracture energy approach for analyzing cracks in concrete, and the numerical analysis is carried out using a modified load control method. The problem of excessive cracking is then studied with four different span-ratios. Based on the numerical results, the crack behavior with respect to the patterns of crack propagation, dissipation of the fracture energy, and effects on the structural integrity are discussed. The mechanisms which cause the excessive cracking are also explained.

• 대한기계학회논문집A
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• 제38권4호
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• pp.409-417
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• 2014

구조물의 파괴는 주로 제조 과정에서 생긴 결함이나 사용 중 국부적인 손상의 원인으로 발생되는 균열에 의해 나타난다. 따라서 구조물이나 관련된 부품들의 균열 성장 과정을 분석하는 것은 구조물의 안정성 확보를 위하여 매우 중요하다. 본 논문에서는 균열의 성장을 분석하기 위해 노치가 있는 시편을 인장 실험하며, 마이크로 포커스 X-선 단층촬영을 이용하여 균열 성장을 관찰하였고, 노치가 있는 시편의 단층촬영의 영상으로부터 3 차원 재구축하여 만든 유한요소 모델과 이상적인 모양의 노치를 만든 유한요소 모델을 XFEM에 적용하여 3 차원 균열 성장의 시뮬레이션을 실시 하였다. 실제 시편의 인장 실험 결과와 시뮬레이션 실험들의 결과를 비교하였고, 보다 정밀한 3 차원적 균열 성장의 분석을 위해서는 실제적인 구조물 및 균열의 형태에 대한 3 차원 모델링이 반드시 실시되어야 함을 확인하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.469-474
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• 1999

The object of study is analysis to joint crack behavior of cracked joint concrete pavement. In the new constructing concrete pavement, joint crack behavior was compared general joint depth D/4 with joint depth D/3 and D/5 that it's environmental effects changed temperature and humidity. After joint saw cutting joint section was predicted crack at joint depth D/5 test section from the result for monitoring development of crack. In the setting of data logger system of the joint section, it's data compared see with the naked eye. In the research, development of crack at the joint section should effect to joint saw timing latter than joint depth. This performance could be the minimum of deterioration to the early curing. In this research, At new constructing of joint concrete pavement of highway, the monitoring system be setting after finished paving and joint sawing. The system and see with the naked eye could be analysis to pavement behaviors from collecting data at the test section. This system could be monitoring shot term and long term. In this report, joint section of crack behavior analysis used to collected data during a month after paving and joint sawing.