• Steel and Composite Structures
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• 제38권3호
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• pp.271-280
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• 2021

In this study, the fatigue property of U rib-to-crossbeam connections in orthotropic steel bridge (OSB) crossbeams under heavy traffic vehicle load was investigated considering the effects of in-plane shear stress. The applicability of an improved structural stress (ISS) method was validated for the fatigue behavior analysis of nonwelded arc-shaped cutout regions in multiaxial stress states. Various types of fatigue testing specimens were compared for investigating the equivalent structural stress, fatigue crack initiation positions, and failure modes with the unified standards. Furthermore, the implications of OSB crossbeams and specified loading cases are discussed with respect to the improved method. The ISS method is proven to be applicable for analyzing the fatigue property of nonwelded arc-shaped cutout regions in OSB crossbeams. The used method is essential for gaining a reliable prediction of the most likely failure modes under a specific heavy traffic vehicle load. The evaluated results using the used method are proven to be accurate with a slighter standard deviation. We obtained the trend of equivalent structural stress in arc-shaped cutout regions and validated the crack initiation positions and propagation directions by comparing them with the fatigue testing results. The implications of crossbeam spans on fatigue property are less significant than the effects of crossbeams.

• Steel and Composite Structures
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• 제42권6호
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• pp.843-853
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• 2022

The fatigue behavior of welded open rib-to crossbeam joints (ORCJ) in orthotropic bridge structures is investigated using a traction structural stress method. The fatigue behaviors of welded open rib-to crossbeam joints have been a subject of study for decades for ensuring operational safety and future design improvement. A mesh-insensitive combination of traction structural stresses in ORCJ was obtained considering the effect of in-plane shear stress and validated by fatigue test results. The proposed method is advantageous for predicting fatigue cracks that initiate from the crossbeam cutout and propagate along the crossbeam. The investigations carried out with the proposed approach reveal that the normal structural stress decreases with the propagation of fatigue cracks, while the ratio of shear stress to normal stress increases. The effect of shear structural stress is significant for the analysis of fatigue behavior of ORCJ in multiaxial stress states.

• Structural Engineering and Mechanics
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• 제60권2호
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• pp.351-363
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• 2016

Exact solutions for stresses, strains, displacements, and the stress concentration factors of a rectangular plate perforated by an arbitrarily located circular hole subjected to in-plane pure shear loading are investigated by two-dimensional theory of elasticity using the Airy stress function. The hoop stresses, strains, and displacements occurring at the edge of the circular hole are computed and plotted. Comparisons are made for the hoop stresses and the stress concentration factors from the present study and those from a rectangular plate with a circular hole under uni-axial and bi-axial uniform tensions and in-plane pure bending moments on two opposite edges.

• 대한건축학회논문집:구조계
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• 제34권9호
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• pp.3-10
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• 2018

While computer environments have been dramatically developed in recent years, as the building structures become larger, the structural analysis models are also becoming more complex. So there is still a need to model one shear wall with one finite element. From the viewpoint of the concept of FEA, if one shear wall is modeled by one finite element, the result of analysis is not likely accurate. Shear wall may be modelled with various finite elements. Among them, considering the displacement compatibility condition with the beam element connected to the shear wall, plane stress element with in-plane rotational stiffness is preferred. Therefore, in order to analyze one shear wall with one finite element accurately, it is necessary to evaluate finite elements developed for the shear wall analysis and to develop various plane stress elements with rotational stiffness continuously. According to the above mentioned need, in this study, the theory about a plane stress element using hierarchical interpolation equation is reviewed and stiffness matrix is derived. And then, a computer program using this theory is developed. Developed computer program is used for numerical experiments to evaluate the analysis results using commercial programs such as SAP2000, ETABS, PERFORM-3D and MIDAS. Finally, the deflection equation of a cantilever beam with narrow rectangular section and bent by an end load P is derived according to the elasticity theory, and it is used to for comparison with theoretical solution.

• Structural Engineering and Mechanics
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• 제58권5호
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• pp.783-797
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• 2016

Exact solutions for stresses, strains, and displacements of a perforated rectangular plate by an arbitrarily located circular hole subjected to both linearly varying in-plane normal stresses on the two opposite edges and in-plane shear stresses are investigated using the Airy stress function. The hoop stress occurring at the edge of the non-central circular hole are computed and plotted. Stress concentration factors (the maximum non-dimensional hoop stresses) depending on the location and size of the non-central circular hole and the loading condition are tabularized.

• Structural Engineering and Mechanics
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• 제53권2호
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• pp.205-226
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• 2015

Finite element method (FEM) is an effective quantitative method to solve complex engineering problems. The basic idea of FEM for a complex problem is to be able to find a solution by reducing the problem made simple. If mathematical tools are inadequate to obtain precise result, even approximate result, FEM is the only method that can be used for structural analyses. In FEM, the domain is divided into a large number of simple, small and interconnected sub-regions called finite elements. FEM has been used commonly for linear and nonlinear analyses of different types of structures to give us accurate results of plane stress and plane strain problems in civil engineering area. In this paper, FEM is used to investigate stress analysis of a shear wall which is subjected to concentrated loads and fundamental principles of stress analysis of the shear wall are presented by using matrix displacement method in this paper. This study is consisting of two parts. In the first part, the shear wall is discretized with constant strain triangular finite elements and stiffness matrix and load vector which is attained from external effects are calculated for each of finite elements using matrix displacement method. As to second part of the study, finite element analysis of the shear wall is made by ANSYS software program. Results obtained in the second part are presented with tables and graphics, also results of each part is compared with each other, so the performance of the matrix displacement method is demonstrated. The solutions obtained by using the proposed method show excellent agreements with the results of ANSYS. The results show that this method is effective and preferable for the stress analysis of shell structures. Further studies should be carried out to be able to prove the efficiency of the matrix displacement method on the solution of plane stress problems using different types of structures.

• 대한토목학회논문집
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• 제6권2호
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• pp.77-83
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• 1986

본 연구에는 전단벽을 가진 프레임의 구조해석을 위한 개선된 해석모델이 소개되었다. 새로이 개발된 12 자유도를 가진 plane stress 요소와 보 요소를 사용하는 컴퓨터 프로그램 SWAN을 이용하여 두 개의 2 차원 구조물의 예에 대한 정적 및 동적해석을 수행하고 그 결과를 널리 사용되고 있는 구조해적용 컴퓨터 프로그램 SAP IV를 사용해서 얻을 결과와 비교 검토한 결과 12 자유도 요소를 사용함으로써 전단벽 요소내의 전단응력의 분포와 전단벽에 연결된 보 요소의 휨 및 전단응력 등이 상당히 정확하게 얻어질 수가 있음이 밝혀졌다.

• Structural Engineering and Mechanics
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• 제61권3호
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• pp.407-417
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• 2017

RC shear walls are considered one of the main lateral resisting members in buildings. In recent years, FRP has been widely utilized in order to strengthen and retrofit concrete structures. A number of experimental studies used CFRP sheets as an external bracing system for retrofitting of RC shear walls. It has been found that the common mode of failure is the debonding of the CFRP-concrete adhesive material. In this study, behavior of RC shear wall was investigated with three different micro models. The analysis included 2D model using plane stress element, 3D model using shell element and 3D model using solid element. To allow for the debonding mode of failure, the adhesive layer was modeled using cohesive surface-to-surface interaction model at 3D analysis model and node-to-node interaction method using Cartesian elastic-plastic connector element at 2D analysis model. The FE model results are validated comparing the experimental results in the literature. It is shown that the proposed FE model can predict the modes of failure due to debonding of CFRP and behavior of CFRP strengthened RC shear wall reasonably well. Additionally, using 2D plane stress model, many parameters on the behavior of the cohesive surfaces are investigated such as fracture energy, interfacial shear stress, partial bonding, proposed CFRP anchor location and using different bracing of CFRP strips. Using two anchors near end of each diagonal CFRP strips delay the end debonding and increase the ductility for RC shear walls.

• 한국전산구조공학회논문집
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• 제24권3호
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• pp.319-328
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• 2011

이 논문은 ESO 기법을 기초로 한 Strut-Tie 모델의 구성을 제안하고 있다. 평면응력 요소를 사용한 기존의 ESO방법과 달리, ESO기법에 의해 최적화된 구조가 트러스와 비슷한 형태를 가지는 사실에 기인하여, Strut-Tie 모델을 통한 전단설계에 트러스 요소를 사용한 ESO기법을 새롭게 적용하였다. 예제들을 통해 제안된 방법이 가장 좋은 Strut-Tie 모델을 찾을 수 있음을 입증하였으며, 앞서 2차원 평면응력 요소와 Strut-Tie 모델의 연관성에 대한 연구를 통해 ESO방법이 효과적으로 사용될 수 있음은 물론 경험하지 못한 특히 복잡한 철근 콘크리트 구조물의 전단설계에 효과적으로 사용이 가능한 대안이 될 수 있을 것으로 판단된다.

• 동력기계공학회지
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• 제10권4호
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• pp.83-89
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• 2006

Curved beams are more efficient in transfer of loads than straight beams because the transfer is effected by bending, shear and membrane action. The finite element method is a versatile method for solving structural mechanics problems and curved beam problems have been solved using this method by many author. In this study, a new three-noded hybrid-mixed curved beam element is proposed to investigate the in-plane flexural vibration behavior of arches depending on the curvature, aspect ratio and boundary conditions, etc. The proposed element including the effect of shear deformation is based on the Hellinger-Reissner variational principle, and employs the quadratic displacement functions and consistent linear stress functions. The stress parameters are then eliminated from the stationary condition of the variational principle so that the standard stiffness equations are obtained. Several numerical examples confirm the accuracy of the proposed finite element and also show the dynamic behavior of arches with various shapes.