• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.67-70
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• 2008

This study is to analyzes the global behavior of frame structures with local cracks in structural members by frame analysis, using the stiffness matrix of cracked frame element. This local compliance is utilized to derive the stiffness matrix of the cracked frame element and the effects of interaction among multiple cracks are also examined. The proposed technique is applied to frame structures with local cracks. Analysis results confirm the possibility of quantitative analysis of a structure damaged with local cracks and the feasibility of the technique as a tool for analyzing the global behavior of frame structures, reflecting effects of local cracks.

• Journal of Korean Society of Steel Construction
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• v.11 no.4 s.41
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• pp.397-407
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• 1999

In this paper, the fatigue safety in the suspension bridge is investigated by using nominal and variable stress, respectively. The technique on structural modeling and the fatigue evaluation using nominal stress are mainly dealt with in this paper. To make the finite element analysis model reflecting the actual structural behavior of the suspension bridge with cross frame, the parametric study is carried out. In this study, the influence of supporting condition. the difference of the results of 2- and 3-D analysis and the number of cross frames modelled in are considered. The nominal stress under the real traffic flow of the bridge is calculated by the combination of the stresses due to the unit DB-24 loading. The nominal stresses for details under consideration are compared with allowable stress ranges specified in the codes and the results are discussed.

• Structural Engineering and Mechanics
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• v.6 no.2
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• pp.201-215
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• 1998

The structural behavior of reinforced concrete frame infilled with a masonry wall is investigated by the method of discontinuous deformation analysis (DDA). An interface element is developed and it is incorporated into DDA to analyze the continuous and discontinuous behavior of the masonry structure. The numerical results are compared with previous research and possess satisfactory agreement. Then the structural behavior and stress distribution of a reinforced concrete frame infilled with a masonry wall subjected to a horizontal force are studied. In addition, the justification of equivalent strut is assessed by the distribution of principal stresses. The results show that the behavior of the masonry structure is highly influenced by the failure of mortar. On the basis of the distribution of principal stress of the masonry wall in the reinforced concrete frame, the equivalent strut can be approximately substituted for the masonry wall without separation and opening. However, the application of equivalent strut to the masonry wall with separation and opening needs further study.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.317-320
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• 2008

Between traffic-induced vibration of a bridge and fatigue damage of its attached structures are very closely related. But any evaluation and design method considering the fatigue damage is not established yet. As an experimental method of evaluation of the fatigue durability, a method based on cumulative damage using a stress range histogram has been often used. However, to use the method, the fatigue durability of unmeasured points could not be evaluated. Then, in this paper, dynamic analysis of a sign frame on a bridge is carried out based on the vibration data of the bridge. And model optimization was performed for good agreement between measured responses and computed responses. As a result, we could get stress range histograms and calculate fatigue durability of unmeasured points.

• Korea-Australia Rheology Journal
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• v.17 no.4
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• pp.171-180
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• 2005

We present numerical results for inertialess elliptic particle suspensions in a Newtonian fluid subject to simple shear flow, using the sliding bi-periodic frame concept of Hwang et al. (2004) such that a particulate system with a small number of particles could represent a suspension system containing a large number of particles. We report the motion and configurational change of elliptic particles in simple shear flow and discuss the inter-relationship with the bulk shear stress behaviors through several example problems of a single, two-interacting and ten particle problems in a sliding bi-periodic frame. The main objective is to check the feasibility of the direct simulation method for understanding the relationship between the microstructural evolution and the bulk material behaviors.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.106-113
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• 2004

The eddy current brake system is a non-contact brake based on the mutual relation between the rail and the frame. Consequently, the accuracy is required in estimating the stress concentration and the deformation of the eddy current brake system. In this paper, the static analysis considering the gravity and the suction force for the deformation and the stress concentration of the main frame of the initially designed eddy current brake system was carried out. The shape of the I-type beam obtained from the optimization was analyzed and compared with the initial model. Also, the initial model was modified based on the optimization model and the result was verified to have the acceptable improvement.

• Steel and Composite Structures
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• v.34 no.3
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• pp.393-407
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• 2020

The braced tube frame system, a combination of perimeter frame and bracing frame, is one of the systems used in tall buildings. Due to the implementation of this system in tall buildings and the high rigidity resulting from the use of general bracing, providing proper ductility while maintaining the strength of the structure when exposing to lateral forces is essential. Also, the high stress at the connection of the beam to the column may cause a sudden failure in the region before reaching the required ductility. The use of Reduced Beam Section connection (RBS connection) by focusing stress in a region away from beam to column connection is a suitable solution to the problem. Because of the fact that RBS connections are usually used in moment frames and not tested in tall buildings with braced tube frames, they should be investigated. Therefore, in this research, three tall buildings in height ranges of 20, 25 and 30 floors were modeled and designed by SAP2000 software, and then a frame in each building was modeled in PERFORM-3D software under two RBS-free system and RBS-based system. Nonlinear time history dynamic analysis is used for each frame under Manjil, Tabas and Northridge excitations. The results of the Comparison between RBS-free and RBS-based systems show that the RBS connections increased the absorbed energy level by reducing the stiffness and increasing the ductility in the beams and structural system. Also, by increasing the involvement of the beams in absorbing energy, the columns and braces absorb less energy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.353-359
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• 2010

For achieving economical fuel consumption, an increase in the load bearing capacity, and for environmental conservation, there is a constant demand for lightweight frames of commercial vehicles used in the transportation industry. In this study, a structural analysis of the frame of a heavy flat-bed trailer was performed to determine the optimal design of a new lightweight frame made of high-strength steel. To identify the key design parameters of the trailer frame, Taguchi's orthogonal array was used in the experiments. Using ANSYS, a commercial FEA program, the frame structure was optimized with respect to stress, deflection, and torsional stiffness by performing stress and vibration analyses. A physical model of the trailer was also built to verify the validity of the numerical analyses. Finally, an on-road fatigue test of the new lightweight frame made of the high-strength steel, ATOS80, was performed to confirm the durability of the new design.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.1 s.244
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• pp.97-104
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• 2006

This paper has investigated the strength of the bogie frame for the Korean tilting train that is being developed in KRRI. In this study, the loading conditions imposed on the bogie frame of tilting train were derived and the static and fatigue strength of the bogie frame has been evaluated. In order to achieve these goals, finite element analysis has been performed and the stress concentration areas were investigated. Based on the analytical results, the static load tests were conducted under the nontilting load conditions and the tilting load conditions. The test results were used to evaluate the fatigue strength of the bogie frame by Goodman diagram.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1402-1405
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• 2005

This paper describes the result of structure analysis of secondary bogie frame. The purpose of the analysis is to evaluate an safety which secondary bogie frame shall be considered fully sufficient rigidity so as to satisfy proper system function under maximum load. Secondary bogie system consist of bogie frame, suspensions, wheel-sets, and brake system. Among these component, the bogie frame is most significant component subjected to the vehicle and passenger loads. The evaluation method is used the JIS E 4207 specification throughout the FEM analysis. The analysis results have been very safety and stable for design load conditions.