• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1379-1386
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• 2013

The present work reports the mismatch limit loads for a V-groove welded pipe for a circumferential crack using finite element (FE) analyses. To integrate the effect of groove angles on mismatch limit loads, one geometry-related slenderness parameter was modified by relevant geometric parameters including the groove angle, crack depth, and root opening based on plastic deformation patterns in the theory of plasticity. Circumferential through-wall cracks are located at the centre of the weldments with two different groove angles ($45^{\circ}$, $90^{\circ}$). With regard to the loading conditions, axial (longitudinal) tension and bending are applied for all cases. For the parent and weld metal, elastic-perfectly plastic materials are considered to simulate and analyze under- and over-matching conditions in plasticity. The overall results from the proposed solutions are found to be similar to the FE results.

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.3
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• pp.139-151
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• 2003

This study was to evaluate and to compare the compressive strength and the displacement effecting the abutment or the residual ridge which are transformed by the angle and the heights of the konus denture inner crown when restorating the unilateral konus denture by using the mandibular canine and the 1st premolar as an abutment. The author made 9 different models for different inner crown heights and konus angles. The inner crown height were divided to 5mm, 6mm, and 7mm and konus angles was divided to $4^{\circ}$, $6^{\circ}$, and $8^{\circ}$. And then in each model, 5kg of $15^{\circ}$ mesial load was stressed on the central fossa of the 1st premolar and the 1st molar. The stresses and displacement were measured using the finite element analysis. The results were as follows 1. The maximum compressive strength was shown on the connective area of the abutment and the denture base. 2. As the angle of the inner crown becomes increased, the compressive strength was shown smaller. 3. As the height of the inner crown becomes increased, the maximum compressive strength was shown smaller while the compressive strength of the root apex and the residual ridge showed larger. 4. When the stress was loaded only on the 1st premolar, the more compressive strength was concentrated on the root apex area of the 1st premolar. 5. When the stress was loaded only on the 1st premolar, the compressive strength was concentrated uniformly on the abutment and the residual ridge. 6. When the stress was loaded only on the 1st molar, the maximum displacement was shown on the distal part of the residual ridge.

• Earthquakes and Structures
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• v.14 no.1
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• pp.11-20
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• 2018

Three-dimensional panels are one of the modern construction systems which can be placed in the category of industrial buildings. There have always been a lot of studies and efforts to identify the behavior of these panels and improve their capacity due to their earthquake resistance and high speed of performance. This study will provide a comparative evaluation of behavior of updated three-dimensional panel's structural components under lateral load in both independent and dependent modes. In fact, this study tries to simultaneously evaluate strengthening effect of three-dimensional panels and the effects of system state (independent, L-shaped and BOX shaped Walls) with reinforcement armatures with different angles on the three-dimensional panels. Overall, six independent wall model, L-shaped, roofed L-shaped, BOX-shaped walls with symmetric loading, BOX -shaped wall with asymmetrical loading and roofed BOX-shaped wall were built. Then the models are strengthened without strengthened reinforcement and with strengthened reinforcements with an angle of 30, 45 and 60 degrees. The applied lateral loading, is exerted by changing the location on the end wall. In BOX-shaped wall, in symmetric and asymmetric loading, the load bearing capacity will be increased about 200 and 50% respectively. Now, if strengthened, the load bearing capacity in symmetric and asymmetric loading will be increased 3.5 and 2 times respectively. The effective angle of placement of strengthened reinforcement in the independent wall is 45 and 60 degrees. But in BOX-shaped and L-shaped walls, the use of strengthened reinforcement 45 degrees is recommended.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.884-892
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• 2006

A friction-type reinforcing member(FRM) is proposed for the purpose of upgrading wind resistant performance of a transmission tower and verified through cyclic loading tests. First, suitable install scheme of the FRM is investigated through numerical analysis. Main-post-reinforcing type and X-brace type installation schemes are examined, and numerical analysis shows that the former is more effective due to the vertical cantilever type behavior of the transmission tower. Based on this result, two types of the FRM's, dissipating energy in slotted belted connections, are proposed. The one utilizes the relative displacement between the FRM and the main post, and the other utilizes that between the separated angles consisting of the FRM as a slip deformation of the slotted bolted connection. Proposed FRM's are installed on each main post of the 1/2 scale substructure models of an actual transmission tower body. From cyclic loading tests, the latter type of the proposed FRM's dissipates energy more effectively and its slip load is controlled by applied torque well, and shares considerable amount of the axial force in the main post.

• Computational Structural Engineering
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• v.9 no.4
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• pp.135-140
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• 1996

Single angle or channel with thin-walled open section can be used as compression member for example as web member in truss. In this case the inevitable eccentricity due to fabrication is commonly neglected in structural design. However eccentricity effect should be considered in the member design, especially in case of compression member. The critical loads of compression members that buckle by twisting or by a combination of bending and twisting are to be determined by solving governing differential equations. In this paper, the investigations are limited to the rolled channels([), equal-leg angles(L), lipped channels(C) and the applied loads are assumed to have some eccentricities.

• 전기의세계
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• v.14 no.3
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• pp.10-17
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• 1965

This paper presents a method of the voltage-reactive power control in the long and short range operations and introduces a conception, "optimum control pattern." The optimum control pattern, aiming at the over-all system control, is defined as the optimum voltage distribution which minimizes the system operating cost under the conditions that the specified power be supplied and the system voltage be kept within the specified bounds. The following procedure was adopted to obtain this optimum pattern. In the first place, a power system was divided into three blocks, namely, load, substation and generator. Lagrange's, multiplier method is applied to each block in turn, paying attention only at the operating voltage distribution. Phase angles at each bus are then modified so that the continuity of active power is maintained. This procedure may be called "block relaxation method with Lagrange's multipliers." In a long range operation, this control pattern determines the optimum installation capacity of reactive power sources. In a short range operation, it also gives the reference state of real time control and the optimum switching capacity of reactive power souces. The real time control problem is also studied from the standpoint of cooperation of control devices such as generators, shunt capacitors, shunt reactors and ratio load controllers. A proposal for the real time control will contribute to the automation of power system operation in the near future. in the near future.

• Journal of Industrial Technology
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• v.18
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• pp.405-415
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• 1998

This thesis is an experimental and numerical research on bearing capacity acting retaining walls close to rigid slopes with stiff angles. Experiments were performed with changing the roughness of adjacent slope to the wall, its inclination, distance between wall and slope. Vertical stress and applied surcharge loads were measured by miniature earth cells and a load cel respectively. Stress distribution Vertical Settlement of surcharge load of rigid model footing were measured by LVDTs. Bearing capacities of surcharge loads were compared with theoretical estimations by using several different methods of limit equilibrium and numerical analysis. For limit equilibrium methods, the modified silo and the wedge theories, proposed by Chung sung gyo and Chung in gyo (1994) were used to analyze test results Based on those modified theories, the particular solution with the boundary condition of surcharge loads on the surface of backfill was obtained to find the stress distributions acting in the backfill and to compare with test results. From results of surcharge test with model wall being very close to the slope, analyzed results by the modified silo theory and to be in the better agreements than other methods.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.11
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• pp.977-982
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• 2015

This study uses finite element analysis to evaluate the forming load of tool entrance angle of the cold forward extrusion molding process of helical gear; this can replace the spur gear applied to the Electronic Parking Brake (EPB) system. A cold forging process is often used in the automobile industry as well as in various industrial machines due to its high efficiency. Finite element analysis is frequently used when interpreting results of the forging process. Formality was evaluated by calculating tooth profile filling rate of helical gear. Change in required forming load was investigated when the entrance angle of forward extrusion tool die was changed from $30^{\circ}$ to $60^{\circ}$, also by finite element analysis. We suggest suitable tool entrance angles.

• Textile Coloration and Finishing
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• v.34 no.2
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• pp.127-133
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• 2022

With the increasing interest in the expression of individuality and appearance of modern people, it is time to conduct research and development of novel hair coloring from various angles. Therefore, taking into account the order of discoloration of hair pigments, we selected a creative and novel emulsion as a novel material for hair coloring, rather than a cosmetic material such as hot water extract using natural products dealt with in previous studies, commercially available hair manicure, and oxidation hair dye for hair. Thus, the change in tensile strength and elongation of hair samples by color was studied. As a result of the study, hair with green emulsion paint had a significantly higher maximum load, maximum stress, maximum elongation and breaking load, breaking stress, breaking elongation values are shown. Maximum in terms of modulus, green emulsion applied hair and the control group were higher in the 0-15s strain and 15-145s sections, respectively, and the tangential modulus value was much higher in the control group than the experimental group hairs in all the 0-145s sections. This study, which analyzes the dynamic changes of hair samples that extend the daily color gamut, will greatly contribute to the development of innovative hair coloring materials in the research and production of hair beauty works, and it is judged that it will also contribute to the development of the beauty industry.

• Geomechanics and Engineering
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• v.28 no.1
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• pp.89-105
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• 2022

The behavior of the soil subgrade is complex and irregular against loads. When modeling, the soil is often replaced by a more straightforward system called a subgrade model. The Winkler method of linear elastic springs is a popular method of soil modeling in which the spring constant shows the modulus of subgrade reaction. In this research, the factors affecting the distribution of the modulus of subgrade reaction of elastoplastic subgrades are examined. For this purpose, critical theories about the modulus of subgrade reaction were examined. A square raft foundation on a sandy soil subgrade with was analyzed at different internal friction angles and Young's modulus values using ABAQUS software. To accurately model the actual soil behavior, the elastic, perfectly plastic constitutive model was applied to investigate a foundation on discrete springs. In order to increase the accuracy of soil modeling, equations have been proposed for the distribution of the subgrade reaction modulus. The constitutive model of the springs is elastic, perfectly plastic. It was observed that the modulus of subgrade reaction under an elastic load decreased when moving from the corner to the center of the foundation. For the ultimate load, the modulus of subgrade reaction increased as it moved from the corner to the center of the foundation.