• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.203-206
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• 2002

The present study proposes a theoretical model for predicting the matrix crack density growth of each layer in composite laminates subjected to thermo-mechanical loads. Each layer with matrix cracks is treated as an equivalent continuum of degraded elastic stiffnesses which are functions of the matrix crack density in each slyer. The energy release rate as a function of the degraded elastic stiffnesses is then calculated for each layer as functions of thermo-mechanical loads externally applied to the laminate. The matrix crack densities of each layer in general laminates are predicted as functions of the thermo-mechanical loads applied to a number of laminates. Comparisons of the present study with experimental data in the open literatures are also provided.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.21-31
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• 1998

In this paper, a thermo-mechanical model for viscous coupling(VC) was suggested and torque equation in viscous mode was derived considering the effects of geometry of the plates, thermo-mechanical dynamics, silicon oil characteristics and dissolved air characteristics in the silicon oil. Theoretical results were in good accordance with experimental results demonstrating that VC thermo-mechanical model and the theoretical equations, response of the torque transmitted, pressure, temperature and time to the hump were investigated. Simulation results showed that filling rate of the silicon oil plays an integral role not only in the steady state torque characteristics but also in determining the time to hump.

• Transactions of Materials Processing
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• v.18 no.7
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• pp.519-530
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• 2009

The study is concerned with shape correction of stamped product using the laser irradiation. As a fundamental study, laser irradiation process has been analyzed through the thermo-mechanical FE analysis. For the purpose of validation, laser scanning experiment has been carried out also. Since the deformation mechanism involved in the laser scanning is extremely complicated due to the highly temperature dependent material properties, the determination of laser scanning pattern is not easy for the application of real stamped parts. A simplified method for the application of springback correction has been suggested with the thermo-mechanical FE analysis.

• Steel and Composite Structures
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• v.16 no.1
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• pp.77-96
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• 2014

In this paper, magneto-thermo-elastic problem of a thick truncated conical shell immersed in a uniform magnetic field and subjected to internal pressure is investigated. Material properties of the shell including the elastic modulus, magnetic permeability, coefficients of thermal expansion and conduction are assumed to be isotropic and graded through the thickness obeying the simple power law distribution, while the poison's ratio is assumed to be constant. The temperature distribution is assumed to be a function of the thickness direction. Governing equations of the truncated conical shell are derived in terms of components of displacement and thermal fields and discretised with the help of differential quadrature (DQ) method. Results are obtained for different values of power law index of material properties and effects of thermal load on displacement, stress, temperature and magnetic fields are studied. Results of the present method are compared with those of the finite element method.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.365-366
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• 2015

This paper describes the analysis on thermo-mechanical characteristics of underground cable termination. Specially, the interface pressures between stress relief cone and XLPE insulation were analysed according to the change of conductor temperature and ambient temperature. This interface pressures were measured by real test with current transformer and chamber and the interface pressure was changed with conductor and ambient temperature. This paper will continue to perform the test with various cases, then the relation between low interface pressure and breakdown will prove with test results in the near future.

• Journal of the Korean Society for Heat Treatment
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• v.16 no.5
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• pp.267-274
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• 2003

The effect of the thermo-mechanical treatment on the microstructural development and the electric conductivity of Cu-Ca alloys are studied for the thixoforming processed rotor of the induction motor The Cu-Ca alloys containing Ca less than 1.0wt% show the electrical conductivity higher than 80% IACS They also show broad melting range over $150^{\circ}C$ which is desirable for the thixoforming process The semi-solid microstructure of cast alloy changes from the dendrite structure to globular structure by prior deformation before reheating. The details of microstructural changes by the thermo-mechanical treatment are discussed.

• Smart Structures and Systems
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• v.19 no.1
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• pp.33-38
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• 2017

This research tries to present a nonlinear thermo-elastic solution for a functionally graded spherical shell subjected to mechanical and thermal loads. Geometric nonlinearity is considered using the Lagrange or finite strain tensor. Non-homogeneous material properties are considered based on a power function. Adomian's decomposition method is used for calculation of nonlinear results. Nonlinear results such as displacement can be evaluated for sphere in terms of different indexes of non-homogeneity. A comprehensive comparison between linear and nonlinear results and evaluation of the percentage of difference between them can be performed in this paper. The obtained results indicate that the improvement of the results due to usage of nonlinear analysis is depending on the non-homogeneous index.

• Steel and Composite Structures
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• v.17 no.5
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• pp.753-776
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• 2014

In this paper, nonlinear vibration and post-buckling analysis of beams made of functionally graded materials (FGMs) resting on nonlinear elastic foundation subjected to thermo-mechanical loading are studied. The thermo-mechanical material properties of the beams are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents, and to be temperature-dependent. The assumption of a small strain, moderate deformation is used. Based on Euler-Bernoulli beam theory and von-Karman geometric nonlinearity, the integral partial differential equation of motion is derived. Then this PDE problem which has quadratic and cubic nonlinearities is simplified into an ODE problem by using the Galerkin method. Finally, the governing equation is solved analytically using the variational iteration method (VIM). Some new results for the nonlinear natural frequencies and buckling load of the FG beams such as the influences of thermal effect, the effect of vibration amplitude, elastic coefficients of foundation, axial force, end supports and material inhomogenity are presented for future references. Results show that the thermal loading has a significant effect on the vibration and post-buckling response of FG beams.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.1
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• pp.1-15
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• 1998

In this paper, thermo-viscoplastic finite element analysis of the effect of tool edge radius on cutting process are performed. The thermo-viscoplastic cutting model is capable of dealing with free chip geometry and chip-tool contact length. The coupling with thermal effects is also considered. Orthogonal cutting experiments are performed for 0.2% carbon steel with tools having 3 different edge radii and the tool forces are measured. The experimental results are discussed in comparison with the results of the FEM analysis. From the study, we confirm that this cutting model can well be applied to the cutting process considered the tool edge radius and that a major causes of the "size effect" is the tool edge radius. With numerical analysis, the effects of the tool edge radius on the stress distributions in workpiece, the temperature distributions in workpiece and tool, and the chip shape are investigated.estigated.

• Computers and Concrete
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• v.5 no.4
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• pp.279-293
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• 2008

In the present paper a 3D thermo-hygro-mechanical model for concrete is used to study explosive spalling of concrete cover at high temperature. For a given boundary conditions the distribution of moisture, pore pressure, temperature, stresses and strains are calculated by employing a three-dimensional transient finite element analysis. The used thermo-hygro-mechanical model accounts for the interaction between hygral and thermal properties of concrete. Moreover, these properties are coupled with the mechanical properties of concrete, i.e., it is assumed that the mechanical properties (damage) have an effect on distribution of moisture (pore pressure) and temperature. Stresses in concrete are calculated by employing temperature dependent microplane model. To study explosive spalling of concrete cover, a 3D finite element analysis of a concrete slab, which was locally exposed to high temperature, is performed. It is shown that relatively high pore pressure in concrete can cause explosive spalling. The numerical results indicate that the governing parameter that controls spalling is permeability of concrete. It is also shown that possible buckling of a concrete layer in the spalling zone increases the risk for explosive spalling.