• Structural Engineering and Mechanics
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• 제5권6호
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• pp.817-837
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• 1997

In the present contribution an interface crack model is introduced which is capable of modelling crack initialisation and growth in aluminium as well as in Fibre Metal Laminates. Interface elements are inserted in a finite element mesh with a yield function which bounds all states of stress in the interface. Hardening occurs after a state of stress exceeds the yield stress of the material. The hardening branch is bounded by the ultimate stress of the material. Thereafter, the state of stress is reduced to zero while the inelastic deformations grow. The energy dissipated by the inelastic deformations in this process equals the fracture energy of the material. The model is applied to calculate the onset and growth of cracking in centre cracked plates made of aluminium and GLARE$^{(R)}$. The impact of the model parameters on the performance of the crack model is studied by comparisons of the numerical results with experimental data.

• 대한기계학회논문집A
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• 제22권1호
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• pp.206-214
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• 1998

When a crack meets bimaterial interface stress singularity depends on the elastic constants of the adjacent materials. In the present study we are going to describe the finite element formulation for problems with a crack to be embedded in the stiffer material$({\mu}_2/{\mu}_1)$. The cubic isoparametric singular element, represented by adequately shifting the mid-side nodes adjacent to the crack tip is constructed to enclose the crack tip. An alternative method to obtain the optimal position of the mid-side nodes of cubic isoparametric elements is presented. In addition, a proper definition for the stress intensity factors of a crack normal to bimaterial interface is provided. It is based upon near a tip displacement solutions. Models for numerical analysis are two dimensional elastic bodies with a through crack under plain strain. The results obtained are compared with the previous solutions.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2823-2827
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• 2000

The dynamic photoelasticity with the aid of Cranz-Shardin type high speed camera system is utilized to record the dynamically propagating behavior of an interface crack. This paper investigates determined the effects of the hole (exited on the path of the crack propagation) on the crack propagation behavior by comparing the experiment isochromatic fringes to the theoretical stress fields.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.127-131
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• 2000

The dynamic photoelasticity with the aid of Cranz-Shardin type high speed camera system is utilized to record the dynamically propagating behavior of an interface crack. This paper investigates determined the effects of the hole (existed on the path of the crack propagation) on the crack propagation behavior by comparing the experiment isochromatic fringes to the theoretical stress fields.

• 한국자동차공학회논문집
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• 제4권3호
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• pp.112-121
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• 1996

Applications of bonded dissimilar materials such as metal/ceramics and resin/metal joints, are very increasing in various industry fields. It is required to find crack propagation direction and path applying to the fracture mechanics on the bonded joint of dissimilar meterials. In this paper, crack propagation direction and path were simulated numerically by using boundary element method. Crack propagation angle is able to easily determine based on the maximum stress concept. Fracture tests of Al/Epoxy dissimilar materials with an interface crack are carried out under various mixed mode conditions by using the specimens of bonded scarf joints. It is found that the experimental results are well coincide with the analysis results of boundary element method.

• 한국생산제조학회지
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• 제5권4호
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• pp.53-62
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• 1996

Recently, ceramic / metal bonded joints have led to inccreasing use of structural materials such as automobile, heat engine in various industries. In this paper, a method to analyze an interface crack under both residual stresses and applied loading was proposed. and some results of boundary element method(BEM) analysis Were presented, Fracture thoughness tests of ceramic/metals bonded joints with an interface crack Were carried out, and the stress intensity factors of these joints Ware analyzed by BEM. Also crack propagtion direction was simulated numerically by using BEM. Crack propagation angle was able to easily determine based on the maximum stress concept. The prediction of fracture strength by the fracture thoughness of the ceramics/metals bonded joints was proposed.

• 한국전산구조공학회논문집
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• 제31권3호
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• pp.121-125
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• 2018

본 연구에서는 굴곡 계면을 따른 균열 진전을 응집 요소를 사용하여 유한요소 해석을 수행하였고 균열 선단에서 복합 모드 하중을 고려하기 위하여 BK 법칙을 적용하였다. 정현파 굴곡 계면을 갖는 이중 외팔보에 하중을 부여하고 복합 모드 응집 법칙에서 응집 강도와 응집 에너지에 따른 하중-변위 선도의 변화를 알아보았다. 응집 강도가 커지면 응집 영역 크기가 상대적으로 작아지고 균열 진전에 따른 하중-변위 선도에 굴곡이 나타나는 것을 보여 주었으며 인장과 전단 응집에너지 비율에 따라 하중의 증가와 하중-변위 선도에 굴곡이 나타나는 것을 보여주었다. 또한 굴곡 계면의 형상에 따른 균열 진전 거동의 영향을 분석하였는데 균열의 형상비가 커지면 균열 진전을 위한 더 큰 균열 분리 에너지가 요구되는 것을 보여 주었다. 굴곡 계면의 형상과 응집 법칙을 변화시켜 파괴 인성을 크게 향상시킬 수 있으며 균열 진전 거동을 변화시킬 수 있게 된다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 봄 학술발표회 논문집
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• pp.95-102
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• 1996

The stress intensity factor for an interface crack in dissimilar elastic and viscoelastic materials is derived and the time-domain boundary element analysis is performed. Numerical results show that the proposed method is very useful for the analysis of the interface crack in elastic and viscoelastic bimaterials.

• 한국안전학회지
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• 제2권3호
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• pp.21-27
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• 1987

The effect of plastic deformation in an interfacial crack is considered. Yield zones are assumed to have the form of a strip along the interface. The crack is subjected to mode III loads at infinity and lies along the interface of two semi-infinite planes with different material properties. The size of the yield zones, the relation between the size of the yield zone and CTOD are obtained in a closed form solution. The J integral also can be obtained in a closed form Solution.

• 전산구조공학
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• 제9권1호
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• pp.93-99
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• 1996

서로 다른 두 재료의 접합면에 균열이 수직으로 위치하고 있을 때, 균열에서의 응력특이성차수는 두 재료의 재료특성치에 따라서 변화하게 된다. 이와 같은 균열문제를 해석하기 위하여 다영역경계요소법을 사용하였다. 균열을 포함하는 등매개 경계요소 중간절점의 위치를 적절히 이동하여 놓음으로써 변위에 대한 정확한 형상함수를 나타내었으며, 아울러 트랙션에 대해서도 정확한 보간차수를 나타내도록 시도하였다. 3절점 경계요소를 이용하여 수치해석을 수행하였으며, 이의 결과를 기존의 해석결과와 비교 검토하였다.