• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.21-28
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• 2003

The use of frequency-dependent spectral element matrix (or dynamic stiffness matrix) in structural dynamics may Provide very accurate solutions, while it reduces the number of degrees of freedom to improve the computational efficiency and cost problems. Thus, this paper develops a spectral element model for the coupled thermoelastic beam-plate moving with constant speed under uniform in-plane tension.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.1
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• pp.37-49
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• 2000

This paper is for the first essential study on the development of unified finite element formulations for solving problems related to the dynamics/thermoelastics behavior of solids. In the first part of formulations, the finite element method is based on the introduction of a new quantity defined as heat displacement, which allows the heat conduction equations to be written in a form equivalent to the equation of motion, and the equations of coupled thermoelasticity to be written in a unified form. The equations obtained are used to express a variational formulation which, together with the concept of generalized coordinates, yields a set of differential equations with the time as an independent variable. Using the Laplace transform, the resulting finite element equations are described in the transform domain. In the second, the Laplace transform is applied to both the equation of heat conduction derived in the first part and the equations of motions and their corresponding boundary conditions, which is referred to the transformed equation. Selections of interpolation functions dependent on only the space variable and an application of the weighted residual method to the coupled equation result in the necessary finite element matrices in the transformed domain. Finally, to prove the validity of two approaches, a comparison with one finite element equation and the other is made term by term.

• Journal of the Korean Society of Safety
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• v.19 no.4 s.68
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• pp.155-160
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• 2004

A simply supported rectangular thin plate with temperature distribution varying over the thickness is analyzed. Since the thermal deflections are large compared to the plate thickness during bending and membrane stresses are developed md as such a nonlinear stress analysis is necessary. For the geometrically nonlinear, large deflection behavior of the plate, the classical von Karman equations are used. These equations are solved numerically by using the finite difference method. An iterative technique is employed to solve these quasi-linear algebraic equations. The results obtained from the suggested method are presented and discussed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.8
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• pp.1253-1260
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• 2001

Transient thermal analysis of a three-dimensional axisymmetric automotive disk brake is presented in this paper. Temperature fields are obtained using a hybrid FFT-FEM scheme that combines Fourier transform techniques and finite element method. The use of a fast Fourier transform algorithm can avoid singularity problems and lead to inexpensive computing time. The transformed problem is solved with finite element scheme for each frequency domain. Inverse transforms are then performed for time domain solution. Numerical examples are presented for validation tests. Comparisons with analytical results show very good agreement. Also, a 3-D simulation, based upon an automotive brake disk model is performed.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.381-386
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• 2000

The brake force of drum brakes for commercial vehicles is applied by a s-cam. First of all the influence of the s-cam load angles and elastic modulus of the pad on the contact pressure distribution between pad and drum was checked by using 3 dimensional finite element model. In the second part, temperature and thermal stress analyses were carried out by an axisymmetric model with constant heat flux and pressure-proportional heat flux. In the case of temperature analysis the heat conduction from the interface to the pad and the drum was modeled using a thin soft film element, so artificial division of the generated heat flux between pad and drum is not necessary. The analysis was performed by ABAQUS/Standard code.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.147-152
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• 2000

This paper presents the thermoelastic analysis and 3-D failure analysis of the carbon/carbon brake disk. The mechanical properties of the carbon/carbon brake disk were measured for both in-plane and out of plane directions. The mechanical properties were used as the input of the thermoelastic analysis and 3-D stress analysis for the brake disk. The gap between rotor clip and clip retainer was an important parameter in the loading transfer mechanism of the rotor. The change of gap was considered separating the mechanical deformation and thermal deformation. Because the rotor clip and clip retainers were not contacted, the clip retainers and rivets were excluded from the rotor analysis model. The disk was modeled by using the cyclic symmetry condition and the contact problem between the rotor disk and rotor clip was considered. From the results of the 3-D stress analysis, the stress concentration at the key hole of the brake disk was confirmed.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.3
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• pp.173-180
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• 2001

In the case of axisymmetric thermal analysis of drum brakes, the distribution of frictional heat produced on the interface and temperature difference between mating frictional faces are very interesting problems to computational researchers. In the first part, the influence of the s-cam load angles and elastic modulus of the pad on the contact pressure distribution between pad and drum was checked by a three dimensional model. In the second part heat conduction from the interface to the pad and the drum was modeled by using a thin interface element, so artificial division of the generated frictional heat between pad and drum is not necessary. Temperature difference between mating frictional faces is successfully modeled by using the interface element. The influence of some parameters on the thermal distribution is checked. The analysis was performed by ABAQUS/Standard code.

• Composites Research
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• v.12 no.6
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• pp.43-52
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• 1999

This paper explains the development of a concurrent engineering system for the rlesign of composite structures. The concurrent engineering system is developed to meet the demand for the better quality products with lower production cost and time. In this study, to compose the architecture of concurrent engineering system, the commercial and noncommercial programs related to design and analysis of composite structures are surveyed and classified. The concurrent engineering system is including various design modules such as design/analysis of composite structures using CLPT and FEM, buckling and post bucking analysis, thermo-elastic analysis of carbon-carbon composite, and optimum design using expert system and genetic algorithm. For the integration and management of softwares, the concurrent engineering system is realized by Microsoft visual $C++{^\circledR}$ that provide multi-tasking and graphic user interface environment.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.2
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• pp.153-161
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• 2009

A domain/boundary decomposition method is applied for efficient analyses of thermo-elasto-viscoplastic damage and contact problems under the assumption of infinitesimal deformation. For the decomposition of a whole domain and contact boundaries, all the equality constraints on the interface and contact interfaces are restated with simple penalty functional. Therefore, the non-linearity of the problem is localized within finite element matrices in a few subdomains and on contact interfaces. By setting up suitable solution algorithms, the computational efficiency can be improved considerably. The general tendency of the computational efficiency is illustrated with some numerical experiments.

• Journal of the Korean earth science society
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• v.21 no.3
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• pp.315-322
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• 2000

In this study, the data used for the models were a set of 56 geologic estimates of long-term fault slip rates. The hest models were those in which mantle drag was convergent on the Transverse Ranges in the San Andreas fault system, and faults had a low friction (${\mu}$= 0.3). It is clearly important to decide whether these cases of low strength are local anomalies or whether they are representative. Furthermore, it would be helpful to determine fault strength in as many tectonic settings as possible. Analysis of data was considered by unsuspected sources of pore pressure, or even to question the relevance of the friction law. To contribute to the solution of this problem, three attempts were tried to apply finite element method that would permit computational experiments with different hypothesized fault rheologies. The computed model has an assumed rheology and plate tectonic boundary conditions, and produces predictions of present surface velocity, strain rate, and stress. The results of model will be acceptably close to reality in its predictions of mean fault slip rates, stress directions and geodetic data. This study suggests some implications of the thermoelastic characteristics to interpret the relationship with very low strength of San Andreas fault system.