• Geomechanics and Engineering
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• v.19 no.5
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• pp.369-381
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• 2019

The objective of this paper is to study the two dimensional deformation in transversely isotropic thermoelastic medium without energy dissipation due to time harmonic sources using new modified couple stress theory, a continuum theory capable to predict the size effects at micro/nano scale. The couple stress constitutive relationships have been introduced for transversely isotropic thermoelastic medium, in which the curvature tensor is asymmetric and the couple stress moment tensor is symmetric. Fourier transform technique is applied to obtain the solutions of the governing equations. Assuming the deformation to be harmonically time-dependent, the transformed solution is obtained in the frequency domain. The application of a time harmonic concentrated and distributed sources have been considered to show the utility of the solution obtained. The displacement components, stress components, temperature change and couple stress are obtained in the transformed domain. A numerical inversion technique has been used to obtain the solutions in the physical domain. The effects of angular frequency are depicted graphically on the resulted quantities.

• Journal of Institute of Convergence Technology
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• v.1 no.1
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• pp.9-12
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• 2011

Structural analysis of a tire is done using a commercial software, ANSYS Workbench. The properties of rubber of the tire is represented using a Mooney-Rivlin model. The bead in the tire is made of structural steel. 3D CAD model of the tire is obtained from a commercial CAD-specialized software, CATIA. Using an imported 3D CAD geometric model, a mesh system with fifty thousand nodes is constructed using ANSYS. A time-variant point force is applied to the rim of the tire, and the deformation of the tire is computed. It is found that both bending and twisting of the tire are observed where the point force is applied. The deformation of the tire is asymmetric, which results in the help of ripping the tire using the helper. It is also found that the deformation undergoes linearly with the applied force. When the force is larger than 1500N, then the deformation becomes larger than the half of the thickness of the tire. In the future, a more realistic rubber model will be applied and validated with the measured data.

• Journal of computational fluids engineering
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• v.16 no.1
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• pp.7-13
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• 2011

The fluid-structure interaction of a towed body is simulated using a developed code, which is based on the flux-difference splitting scheme on the hybrid Cartesian/immersed boundary method. To improve the stability in the coupling between the fluid and structure domains, a scheme is used, in which the effects of structure deformation are treated implicitly. The developed code is validated for the fluid-structure interaction problem through comparisons with other results on the vortex-induced vibration of elastically mounted cylinders. To simulate behavior of a towed body, an asymmetric tension modelling for a towing cable is suggested. In the suggested model, the tension is proportional to the elongation of the cable, but the cable has no effect on the body motion whenever the distance between the endpoints of the cable is smaller than the original length of the cable. The fluid-structure interactions of a towed body are simulated on the basis of different parameters of the towing cables. It is observed that the suggested tension model predicts the snapping for a shorter towing cable, which is in accordance with the reported results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.152-157
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• 2003

Process design of hot forging, asymmetric to symmetric rib-web shape steel, which is used for the turnout of railway express has been investigated. Owing to the big difference in shape between the initial billet and the final forged product, it is impossible to hot forge the rail in a single step. Therefore, multi step forging as well as die design for each step are necessary for the production. The deformation behavior during hot forging has been analyzed by the numerical simulation through commercial FEA software, $DEFORM^{TM}$-2D. Modification of the design and repeated simulation have been carried out on the basis of the simulation result. For comparison with the simulation results. flow analysis experiment using plasticine has been also carried out. The results of the flow analysis experiment showed good agreement with those of the simulation. Therefore, the developed process design could be applied to the actual production.

• Transactions of Materials Processing
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• v.12 no.5
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• pp.479-486
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• 2003

This paper presents an elastoplastic analysis for spent nuclear fuel disposal container and its 50 cm thick bentonite buffer to predict the collapse of the container while the horizontal asymmetric sudden rock movement of 10 cm is applied on the composite structure. This sudden rock movement is anticipated by the earthquake etc. at a deep underground. Elastoplastic material model is adopted. Drucker-Prager yield criterion is used for the material yield prediction of the bentonite buffer and von-Mises yield criterion is used for the material yield prediction of the container. Analysis results show that even though very large deformations occur beyond the yield point in the bentonite buffer, the container structure still endures elastic small strains and stresses below the yield strength. Hence, the asymmetric 50 cm thick bentonite buffer can protect the container safely against the 10 cm sudden rock movement by earthquake etc.. Analysis results also show that bending deformations occur in the container structure due to the shear deformation of the bentonite buffer. The finite element analysis code, NISA, is used for the analysis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.132-135
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• 2003

Asymmetric rolling, in which the ratio of the rotation rates of the upper and lower rolls was 2, has been used to introduce an intense plastic shear strain for the purpose of grain refinement and developing shear deformation textures through the sheet thickness to improve the strength and plastic strain ratio of AA1050 aluminum alloy sheets. The alloy sheets were rolled at room temperature without lubrication. The textures and microstructures of the sheets were investigated by x-ray diffraction and electron back-scattered diffraction (EBSD) analyses with emphasis on effects of combinations of rot ling directions.

• Transactions of Materials Processing
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• v.26 no.6
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• pp.333-340
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• 2017

The cyclic hardening behavior of transformation-induced plasticity (TRIP) steels shows tension-compression asymmetry known to be attributed to transformation of retained austenite into martensite during deformation. In this work, YoshidaUemori hardening model was used to represent the asymmetric hardening behavior of TRIP1180 steel. Yoshida-Uemori hardening model parameters were obtained from three sets of data: tension-compression, compression-tension, and a combination of the two. Material models were validated for U-bending and springback.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.64-66
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• 2007

Asymmetric rolling, where circumferential velocities of the upper and lower rolls differ, can be one method to change texture of magnesium alloy sheet by introducing shear deformation throughout the thickness of a sheet. In this study, the texture, microstructure and mechanical properties of AZ31 Mg sheets has been investigated during the symmetrical rolling procedure and the asymmetric rolling procedures of different roll speeds with different roll diameters. Texture of Mg alloy sheets were evaluated by using X-ray diffraction and ODFs were calculated using ADC method. The major texture of rolled specimens can be expressed by ND//(0001) fiber texture. The major fiber texture changed according to the rolling processes and such a slight difference of texture changes the formability of sheets. The mechanical properties were enhanced during asymmetrical rolling.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.4
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• pp.450-457
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• 2018

The determination of assembly sequence in general mechanical assemblies plays an important role in terms of manufacturing cost, duration and quality. In the production of ships and offshore plants, the consideration of productivity factors and welding deformation is crucial in determining the optimal assembly sequence. In shipbuilding and offshore industries, most assembly sequence planning has been done according to engineers' decisions based on extensive experience. This may result in error-prone planning and sub-optimal sequence, especially when dealing with unfamiliar block assemblies composed of dozens of parts. This paper presents an assembly sequence planning method for block assemblies. The proposed method basically considers geometric characteristics of blocks to determine feasible assembly sequences, as well as assembly process and productivity factors. Then the assembly sequence with minimal welding deformation is selected based on simplified welding distortion analysis. The method is validated using an asymmetric assembly model and the results indicate that it is capable of generating an optimal assembly sequence.

• The Journal of the Petrological Society of Korea
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• v.13 no.4
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• pp.179-190
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• 2004

Precambrian metamorphic rocks of Yeongyang-Uljin area, which is located in the eastern part of Sobaegsan Massif, Korea, are composed of Pyeonghae, Giseong, Wonnam Formations and Hada leuco granite gneisses. These show a zonal distribution of WNW-ESE trend, and are intruded by Mesozoic igneous rocks and are unconformably overlain by Mesozoic sedimentary rocks. This study clarifies the deformation history of Precambrian metamorphic rocks after the formation of gneissosity or schistosity on the basis of the geometric and kinematic features and the forming sequence of multi-deformed rock structures, and suggests that the geological structures of this area experienced at least four phases of deformation i.e. ductile shear deformation, one deformation before that, at least two deformations after that. (1) The first phase of deformation formed regional foliations and WNW-trending isoclinal folds with subhorizontal axes and steep axial planes dipping to the north. (2) The second phase of deformation occurred by dextral ductile shear deformation of top-to-the east movement, forming stretching lineations of E-W trend, S-C mylonitic structure foliations, and Z-shaped asymmetric folds. (3) The third phase deformation formed I-W trending open- or kink-type recumbent folds with subhorizontal axes and gently dipping axial planes. (4) The fourth phase deformation took place under compression of NNW-SSE direction, forming ENE-WSW trending symmetric open upright folds and asymmetric conjugate kink folds with subhorizontal axes, and conjugate faults thrusting to the both NNW and SSE with drag folds related to it. These four phases of deformation are closely connected with the orientation of regional foliation in the Yeongyang-Uljin area. 1st deformation produced regional foliation striking WNW and steeply dipping to the north, 2nd deformation locally change the strike of regional foliation into N-S direction, and 3rd and 4th deformations locally change dip-angle and dip-direction of regional foliation.