• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.11a
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• pp.151-156
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• 1997

In this thesis, the safety assessment of the steel box girder bridge were studied. From the structural analysis results of the steel box girder bridge, bending moment and shear force were calculated, and these element force was applied to the safety assessment of the steel box girder bridge.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.221-224
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• 2012

This paper presents the strength safety of a hybrid alarm valve by a finite element analysis. The stress and strain of a conventional hybrid alarm valve are calculated for the given maximum test pressure of 2MPa. Especially, the FEM computed maximum stress of a conventional hybrid valve is only 18.6% of yield strength, 370MPa. This means that the conventional valve is designed with a thick thickness of a valve structure. But, new hybrid alarm valve model, which is developed by optimized design method in this study, shows more low level of 43% in maximum stress and strain compared with that of a conventional hybrid valve. These results may recommend the reduction of a weight and a dimension for an optimized hybrid alarm valve.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.101-107
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• 2004

Recently the objective of vehicle design was focused on the crash safety and the energy saving. For the energy saving vehicle structures must be light weight, but for the crash safety some energy absorbing elements must be added. In this paper hybrid structure which consists of a steel and a FRP was studied on the energy absorption characteristics under the impact load by finite element method. Test results of the other researchers were compared with that of computer simulation on this simple hybrid structure. Side rail of vehicle front structure was replaced with hybrid materials for the application of the vehicle structure. 35mph frontal crash simulation was performed with hybrid structure and with conventional steel structure. By the adoption of hybrid structure, the improvement of energy absorption characteristics and reduction of weight was observed under the frontal crash simulation.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.86-93
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• 2003

These days, automobile industry pays considerable attention to child occupant safety. As the US adopted requirements for universal and uniform anchor systems for child restraints, manufacturers for child seats put an enormous effort to improve the protective properties of Child Restraint System (CRS). Various standards have been studied and announced by different countries. The anchorage system is the most important in the CRS and the rules of universal anchor are to provide devices which are independent of safety belts. A new concept called International Standard Organization Fixture (ISOFIX) has been announced. It suggests some designs for the CRS. In this study, the suggested designs are evaluated with domestic products. Tests are performed and the results are incorporated into a finite element modeling process. As the finite element model is established, various numerical tests are conducted and the numerical results are discussed. A commercial software system is utilized for the nonlinear finite element analysis.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.122-129
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• 2004

Finite element analysis was performed to analyze structural safety of a new heavy-duty direct injection diesel engine. A half section of the in-line 6-cylinder engine was selected as a computational domain. A mapping method was used to project heat transfer coefficients from CFD results of engine coolant flow onto the FE model. The accurate setting of thermal boundary condition on the FE model was expected to result in improved prediction of temperature, cylinder bore distortion, and stresses. Characteristics of high cycle fatigue were investigated by assuming the engine was operated under the following five loading conditions repeatedly; assembly force, assembly force with thermal loading, alternating maximum gas pressure loading at each cylinder combined with assembly force and thermal loading. Distribution of fatigue safety factor was calculated by using it Haigh diagram in which the maximum and the minimum stresses were selected from the five loading cases.

• Steel and Composite Structures
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• v.23 no.3
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• pp.303-315
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• 2017

This paper describes the finite element model for predicting the fundamental performance of embedded steel column base connections under monotonic and cyclic loading. Geometric and material nonlinearities were included in the proposed finite element model. Bauschinger and pinching effects were considered in the simulation of embedded column base connections under cyclic loading. The degradation of steel yield strength and accumulation of plastic damage can be well simulated. The accuracy of the finite element model is examined by comparing the predicted results with independent experimental dataset. It is demonstrated that the finite element model accurately predicts the behaviour and failure models of the embedded steel column base connections. The finite element model is extended to carry out evaluations and parametric studies. The investigated parameters include column embedded length, concrete strength, axial load and base plate thickness. Moreover, analytical models for predicting the initial stiffness and bending moment strength of the embedded column base connection were developed. The comparison between results from analytical models and those from experiments and finite element analysis proved the developed analytical model was accurate and conservative for design purposes.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.10a
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• pp.40-45
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• 1989

In order to take account of the statistical properties of random variables used in the structural analysis, the conventional approach usually adopts the safety factor based on past experiences for the qualitative assessment of structural safety problem. Recently, new approach based on the probabilistic concept has been applied to the assessment of structural safety in order to circumvent the difficulties of the conventional approach in choosing the appropriate safety factor. Thus, computer program called "Probabilistic finite element method" is developed by incorporation the probabilistic concept into the conventional matrix method in order to investigate the effects of the random variables on the final output of the structural analysis. From the comparison of some examples, it can be concluded that the PFEM developed in this study deals with consistently with the uncertainty of random variables and provides the rational tool for the assessment of structural safety of plane frame.

• Journal of Auto-vehicle Safety Association
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• v.13 no.4
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• pp.99-105
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• 2021

Vehicle occupant postures are anticipated to vary more widely during automated driving and to become more significant in terms of the autonomous vehicle safety. Experimental and computational approaches are needed to investigate and evaluate occupant behaviors during automated driving in general. However the validity and effect of such occupant postures are unknown, thus it is necessary to examine occupant behaviors and injury countermeasures for various occupant postures. This study was focused on the development and evaluation of restraint system model for occupant behavior examinations in the first step according to autonomous vehicle occupant safety. The finite element models of dummy and restraint system were set up and simulation results showed overall model performance and safety tolerances of different reclined occupant postures during frontal impact loading.

• Journal of the Korean Society of Safety
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• v.21 no.2 s.74
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• pp.143-149
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• 2006

This paper deals with the space-time finite element analysis of two-dimensional vibration problem with a single variable. The method of space-time finite elements enables the simpler solution than the usual finite element analysis with discretization in space only. We present a discretization technique in which finite element approximations are used in time and space simultaneously for a relatively large time period. The weighted residual process is used to formulate a finite element method for a space-time domain. A stability problem is described and some investigations for chosen type of rectangular space-time finite elements are carried out. Instability is caused by a too large time step of successive time steps in the traditional time-dependent problems. It has been shown that the numerical stability of time-stepping on the larger time steps is quite good. The unstructured space-time finite element not only overcomes the shortcomings of the stability in the traditional numerical methods, but it is also endowed with the features of an effective computational technique. Some numerical examples have been presented to illustrate the efficiency of the described method.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.376-386
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• 2020

The aim of this study was to develop a new efficient strategy that uses the Vector form Intrinsic Finite-element (VFIFE) method to conduct the static and dynamic analyses of marine pipes. Nonlinear problems, such as large displacement, small strain, and contact and collision, can be analyzed using a unified calculation process in the VFIFE method according to the fundamental theories of point value description, path element, and reverse motion. This method enables analysis without the need to integrate the stiffness matrix of the structure, because only motion equations of particles established according to Newton's second law are required. These characteristics of the VFIFE facilitate the modeling and computation efficiencies in analyzing the nonlinear dynamic problem of flexible pipe with large deflections. In this study, a three-dimensional (3-D) dynamical model based on 3-D beam element was established according to the VFIFE method. The deep-sea flexible pipe was described by a set of spatial mass particles linked by 3-D beam element. The motion and configuration of the pipe are determined by these spatial particles. Based on this model, a simulation procedure to predict the 3-D dynamical behavior of flexible pipe was developed and verified. It was found that the spatial configuration and static internal force of the mining pipe can be obtained by calculating the stationary state of pipe motion. Using this simulation procedure, an analysis was conducted on the static and dynamic behaviors of the flexible mining pipe based on a 1000-m sea trial system. The results of the analysis proved that the VFIFE method can be efficiently applied to the static and dynamic analyses of marine pipes.