• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.2
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• pp.400-408
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• 1992

In this paper, analysis of temperature and stress distributions in the roll for a twin roll continuous casting process was carried out. Firstly, several state equations were set up to determine the temperature distribution in the roll using finite difference method. Secondly, thermal stress in the roll was calculated numerically. Also, stress distribution due to the roll pressure was calculated to determine the effect of the roll pressure. For analysis of temperature distributions and the stress states of the roll, there are three kinds of roll materials, 2ICrMoV5. 11, CuCo/NiBe, CuCrZr and three types of cooling system were used.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.3
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• pp.41-52
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• 1990

In this study are determined the unsteady temperature and thermal stress fields for a domestic 4-cylinder, 4-cycle gasoline engine cylinder head by the three-dimensional finite element method. A representative part of the cylinder head is modelled as a combination of hexahedron isoparametric elements, and the time-dependent temperature and the heat transfer coefficient of the gas are imposed as the thermal boundary conditions for the engine speeds of 500 rpm and 2000 rpm. The obtained results, which are represented graphically, indicate that the amplitudes of temperature fluctuation during a cycle are about 10.deg. C and 3.deg. C respectively on the surface of combustion chamber, and the maximum temperature fields occur at 30.deg. , 10.deg. respectively before the initiation of the exhaust stroke. Thermal stress fields due to non-uniform temperature distributions show that compressive stress is much larger than tensile stress throughout a cycle. It is also found that the compressive stress varies with substantial amplitude between the exhaust port and ignition plug hole, and the high tensile stress with small fluctuation occurs between exhaust port and the adjacent head bolt hole.

• Journal of the Korean Society for Heat Treatment
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• v.14 no.4
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• pp.228-234
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• 2001

The present study was an attempt for systematic data conversion between FDM and FEM in order to evaluate the thermal stress distribution during quenching process. It has been generally recognized that FDM is efficient in flow and temperature analysis and FEM in that of stress. But it induced difficulty and tedious work in analysis that one uses both FDM and FEM to take their advantages because of the discrepancy of nodes between analysis tools. So we proposed field data conversion procedure from FDM to FEM in 3-dimensional space, then applied this procedure to analysis of quenching process. The simulation procedure calculates the distributions of temperature and microstructure using FDM and microstructure evolution equations of diffusion and diffusionless transformation. FEM was used for predicting the distributions of thermal stress. The present numerical code includes coupled temperaturephase transformation kinetics and temperature-microstructure dependent material properties. Calculated results were compared with previous experimental data to verify the method, which showed good agreements.

• Advances in materials Research
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• v.9 no.1
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• pp.15-32
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• 2020

In this article, an analytical solution is presented for the steady-state axisymmetric thermal stress distributions in a composite hollow cylinder. The cylinder is composed of two isotropic and anisotropic materials which is subjected to the thermal boundary conditions of convective as well as radiative heating and cooling on the inner and outer surfaces, respectively. The solution of the temperature is obtained by means of Bessel functions and the thermal stresses are developed using Potential functions of displacement. Numerical results are derived for a cylinder which is similar to a gas turbine combustor and showed that the maximum temperature and thermal stresses (radial, hoop, axial) occurred in the middle point of cylinder and the values of thermal stresses in anisotropic cylinder are more than the isotropic cylinder. It is worthy to note that the values of the thermal conditions which estimated in this research, not to be presented in any other papers but these values are very accurate in calculation.

• Steel and Composite Structures
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• v.20 no.4
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• pp.813-832
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• 2016

This research deals with the behavior of Composite Box Girder Bridges (CBGBs) subjected to environmental effects such as solar radiation, atmospheric temperature, and wind speed. It is based on temperature and thermal stress results, which were recorded hourly from a full-scale experimental CBGB segment and Finite Element (FE) thermal analysis. The Hemi-cube method was adopted to achieve the accuracy in temperature distributions and variations in a composition system during the daily environmental variations. Analytical findings were compared with the experimental measurements, and a good agreement was found. On the other hand, parametric investigations are carried out to investigate the effect of the cross-section geometry and orientation of the longitudinal axis of CBGB on the thermal response and stress distributions. Based upon individual parametric investigations, some remarks related to the thermal loading parameters were submitted. Additionally, some observations about the CBGB configurations were identified, which must be taken into account in the design process. Finally, this research indicates that the design temperature distribution with a uniform differential between the concrete slab and the steel girder is inappropriate for describing the thermal impacts in design objective.

• Journal of the Korean Ceramic Society
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• v.43 no.7 s.290
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• pp.415-420
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• 2006

The residual stresses in the interface region of the Thermal Barrier Coating (TBC)/Thermally Grown Oxide (TGO)/Bond Coat (BC) were calculated on the TBC-coated superalloy samples using a Finite Element Method (FEM). It was found that the stress distribution of the interface boundary was dependent upon mainly the geometrical shape or its aspect ratio and the thickness of TGO layer, which was formed by growth and swelling behavior of oxide layer. Maximum compressive residual stress in the TBC/TGO interface is higher than that of the TGO/bond coat interface, and the tensile stress had nothing to do with change of an aspect ratio. The compressive residual stresses in the TBC/TGO and TGO/bond coat interface region increased gradually with the TGO growth.

• Bulletin of the Society of Naval Architects of Korea
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• v.10 no.1
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• pp.15-20
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• 1973

In this paper, it is desired to show a simplified analytical method in estimating the thermal stresses in the heat affected zone of butt welded joint. A finite strip as shown in Fig.1 is taken as a analytical model for stress analysis. Expressing the temperature distributions by Fourier series, the thermal stresses are obtained. From the numerical sample calculation, the following results can be obtained. (1) Thermal stresses can be estimated by the sujected method. (2) The stress component, which is parallel to the weld direction is the largest stress component in major part of the strip. (3) In obtaining a stress component for the engineering purpose, length of the strip can be treated as five times of the thickness with same degree of convergency.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.785-790
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• 2002

Distributions of residual stress in diffusion bonding of dissimilar materials intermetallics TiAl to steel 40Cr were simulated by FEM calculation. Results showed that destructive residual stresses presented in the minute area adjacent to bond-line of the base material with smaller coefficient of thermal expansion. Reducing bonding temperature and diminishing bonding time are in favor of the mollification of interface tresses.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.385-390
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• 2004

An unique ceramic material produced through unidirectional solidification with eutectic composition of two-phase oxides was introduced recently. This composite material has the microstructure of coupled networks of two single crystals interpenetrate each other without grain boundaries. Depending on this microstructure this material, called Melt Growth Composite (MGC), can sustain its room temperature strength up to 1$700^{\circ}C$ (near its melting point) and offer strong oxidization-resistant ability, making its characteristics quite ideal for the gas turbine application. The research project on MGC started in 2001 with the objective of establishing component technologies for MGC application to the high temperature components of the gas turbine engine. MGC turbine nozzles are expected to improve efficiency of gas turbine. However, reduction of the thermal stress is required since high thermal stress is easily generated in MGC turbine nozzles due to temperature distribution. Firstly, the hollow nozzle shape was optimized to reduce thermal stress using numerical analysis. From the results of the first hot gas flow tests, the thermal stress due to span-wise temperature distribution was required to be reduced, and separated nozzle to three pieces was designed. This was tested in hot gas flow at 140$0^{\circ}C$ level, and temperature distributions on the nozzle surface were obtained and stress field was evaluated.

• Structural Engineering and Mechanics
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• v.58 no.4
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• pp.627-639
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• 2016

The analysis of thermally induced stresses in engineering structures is a very important and necessary task with respect to design and modeling of pressurized containers, heat exchangers, aircrafts segments, etc. to prevent them from failure and improve working conditions. So, the purpose of this study is to investigate elasto-plastic thermal stresses and deformations in a thin annular plate embedded into rigid container. To this end, analytical research devoted to mathematically and physically rigorous stress/strain analysis is performed. In order to evaluate the effect of logarithmic thermal gradients, commonly applied to structures which incorporate thin plate geometries, different thermal parameters such as temperature mismatch and varying constraint temperature were introduced into the model of elastic perfectly-plastic annular plate obeying the von Mises yield criterion with its associated flow rule. The results obtained may be used in sensitive to temperature differences aircraft structures where the thermal effects on equipment must be kept in mind.