• Special Issue of the Society of Naval Architects of Korea
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• 2011.09a
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• pp.82-89
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• 2011

In general, a number of lifting lugs have been used in shipbuilding industry and the D-type lugs are mainly used. The aim of this paper is to increase the cycle of the use and to reduce the size of lifting lugs to introduce lightweight shackle. In this study, nonlinear elasto-plastic analysis has been performed to confirm the ultimate strength of lifting lugs. In order to evaluate the proper design-load distribution around lug eye, the contact force between lifting lug and shackle pin has been realized by gab element model. Gap element modeling and nonlinear analysis are carried out using the finite element program MSC/PATRAN & ABQUS. Additionally the ultimate strength tests were performed to verify the structural adequacy of newly designed lifting lug and to insure safety of it. The D-10, 15, 20 & 40 ton models which are mainly used in the block erection are selected in the strength test. According to the results of the analysis and strength test, the ultimate strength of the newly designed lifting lugs has been estimated to exceed 3 times of design working load.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.4
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• pp.59-65
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• 2003

With the fast growth of shipbuilding industry, in recent years several hundreds of thousands of lifting lugs for a year have been used. This paper is aimed at maximizing the recovering use of lifting lugs. In this study, we have evaluated the structural strength for present and modified lifting lugs under in-plane and out-of-plane load conditions. For this purpose, the equivalent stresses have been calculated by nonlinear elasto-plastic analysis using the finite element program ABAQUS. At the same time, the contact conditions between lifting lug and shackle pin are also considered.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.502-505
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• 2006

The Purpose of this study is to offer an appropriate and reliable safety evaluation method the reinforced concrete members like as reinforced concrete deep beams and reinforced concrete columns, etc. A nonlinear finite element analysis program named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology) was used to evaluate the ultimate strength analytically for the reinforced concrete members that have complicated mechanical behaviors. The nonlinear material model for the reinforced concrete is composed of models for characterizing the behavior of the concrete, in addition to a model for characterizing the reinforcing bars. The proposed numerical method for the safety evaluation of reinforced concrete bridge structures that is consisted of reinforced concrete member is verified by comparison with reliable experimental results.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.5
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• pp.221-230
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• 2014

The purpose of this study is to investigate the seismic performance of hollow RC bridge columns with reinforcement details for material quantity reduction. The proposed reinforcement details provide economy, are rational and shorthen the construction periods. The accuracy and objectivity of the assessment process can be enhanced by using a sophisticated nonlinear finite element analysis program. Solution of the equations of motion is obtained by numerical integration using Hilber-Hughes-Taylor (HHT) algorithm. The adopted numerical method gives a realistic prediction of seismic performance throughout the input ground motions for several test specimens investigated. As a result, the proposed reinforcement details for material quantity reduction develop equal performance to that required for existing reinforcement details.

• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.153-164
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• 2000

Numerical studies were carried out to investigate long-term behavior of flat plates, subjected to combined in-plane compressive and transverse loads. For the numerical studies, a computer program of nonlinear finite element analysis was developed. It can address creep and shrinkage as weel as geometrical and material nonlinearity, and also it can address various load combinations and loading sequences of transverse load, in-plane compressive load and time. This numerical method was verified by comparison with the existing experiments. Parametric studies were performed to investigate the strength variations of flat plates with four parameters; 1) loading sequence of floor load, compressive load and time 2) uniaxial and biaxial compression 3) the ratio of dead to live load 4) span length. Through the numerical studies, the behavioral characteristics of the flat plates and the governing load combinations were examined. These results will be used to develop a design procedure for the long-term behavior of flat plates in the future.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.357-362
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• 2011

Air springs are prevalently used as suspension in train. However, air springs are seldom used in automobiles where they improve stability and comfort by enhancing the impact-relief, breaking, and cornering performance. Thus, this study proposed a new method to analyze air springs and obtained some reliable design parameter which can be utilized in vehicle suspension system in contrast to conventional method. Among air spring types of suspension, this study focused on sleeve type of air spring as an analysis model since it has potential for ameliorating the quality of automobiles, specifically in its stability and comfort improvement by decreasing the shock through rubber sleeve. As a methodology, this study used MARC, as a nonlinear finite element analysis program, in order to find out maximum stress and maximum strain depending on reinforcement cord's angle variation in sleeves. The properties were found through uniaxial tension and pure shear test, and they were developed using Ogden Foam which is an input program of MARC. As a result, the internal maximum stresses and deformation according to the changes of cord angle are obtained. Also, the results showed that the Young's modulus becomes smaller, then maximum stresses decrease. It is believed that these studies can be contributed in automobile suspension system.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.135-136
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• 2010

In this paper, using nonlinear finite element analysis program, we verify the energy dissipation mechanism through stress-strain curve of material with applied steel and concrete acting role of reinforced concrete (RC) column that subjected to cyclic loading with axial force

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.4018-4023
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• 2010

Various kinds of shear connector such as headed stud, channel, perforated steel plate and others are commonly used to transfer stress and present composite performance in composite structures, and many researches have been conducted to improve the characteristics of different types of shear connectors. It is focused in this study on the bending performance of steel pipe pile cap with the open type perforated shear connector for the composite connection to the spread footing. Nonlinear analysis was conducted, using ABAQUS, a finite element analysis program, to obtain information for determining the characteristics of the structure and to allow various parametric analysis for bending performance of steel pipe pile cap with the open perforated shear connector.

• Composites Research
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• v.12 no.5
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• pp.98-109
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• 1999

An investigation has been performed to develop a nonlinear finire element method for the analysis of the long-term behavior of an artificial hip joint. The three dimensional multi-layered brick element is used to analyze the design performances of hip prodtheses with various materials and the thick laminated composite hip prostheses with various layup sequences. The used element can accommodate the varying material properties of the element and allow the ply-drop-off along the eleement edge. The nonlinear finite element analysis program has been verified by the comparison with the exact solution of the bean problem subjected to uniaxial loading. By using the program, the density changes and strength ratios of artificial hip joint are calculated according to the hip prosthesis materials and the layers of composite hip prosthesis. The numerical results are easily applied to evaluate design performances of a hip prosthesis, and decrease the difficulty and time of hip prosthesis design.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.165-175
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• 2009

With the current move towards adopting mechanistic-empirical concepts in the design of pavement structures, state-of-the-art mechanistic analysis methodologies are needed to determine accurate pavement responses, such as stress, strain, and deformation. Previous laboratory studies of pavement foundation geomaterials, i.e., unbound granular materials used in base/subbase layers and fine-grained soils of a prepared subgrade, have shown that the resilient responses followed by nonlinear, stress-dependent behavior under repeated wheel loading. This nonlinear behavior is commonly characterized by stress-dependent resilient modulus material models that need to be incorporated into finite element (FE) based mechanistic pavement analysis methods to predict more realistically predict pavement responses for a mechanistic pavement analysis. Developed user material subroutine using aforementioned resilient model with nonlinear solution technique and convergence scheme with proven performance were successfully employed in general-purpose FE program, ABAQUS. This numerical analysis was investigated in predicted critical responses and domain selection with specific mesh generation was implemented to evaluate better prediction of pavement responses. Results obtained from both axisymmetric and three-dimensional (3D) nonlinear FE analyses were compared and remarkable findings were described for nonlinear FE analysis. The UMAT subroutine performance was also validated with the instrumented full scale pavement test section study results from the Federal Aviation Administration's National Airport Pavement Test Facility (FAA's NAPTF).