• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.71-78
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• 2007

There have been continuous efforts to automate welding processes. This automation process could be said to fall into two categories, weld seam tracking and weld quality evaluation. Recently, the attempts to achieve these two functions simultaneously are on the increase. For the study presented in this paper, a vision sensor is made, and using this, the 3 dimensional geometry of the bead is measured in real time. For the application in welding, which is the characteristic of nonlinear process, a fuzzy controller is designed. And with this, an adaptive control system is proposed which acquires the bead height and the coordinates of the point on the bead along the horizontal fillet joint, performs seam tracking with those data, and also at the same time, controls the bead geometry to a uniform shape. A communication system, which enables the communication with the industrial robot, is designed to control the bead geometry and to track the weld seam. Experiments are made with varied offset angles from the pre-taught weld path, and they showed the adaptive system works favorable results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.3
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• pp.253-260
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• 1999

Main objective of this study is to examine the hysteretic behaviors and to evaluate the capacity of precast concrete (PC) large panel structures simulated from the prototype of 15-story building, Two 1/2 scaled precast concrete wall specimens and one monolithic reinforced concrete specimen were designed and tested under the cyclic loading conditions. The main parameter of test specimens in PC large panel structure is the type of details for vertical continuity of vertical steel in horizontal joint. Also the behaviors of PC large panel structures are compared with that of monolithic reinforcement concrete wall structure. From the results, the stiffness and energy dissipation ratio of the precast concrete specimens are shown little bit lower than those of monolithic reinforced concrete specimen. In the PC large panel structures, the specimen connected vertically by welding (strong connection) showed higher strength than that of the specimen connected vertically by joint box. However the failure pattern of the former showed more brittle than that of the latter due to the diagonal compressive failure of wall panels.

• Journal of Korean Society of Steel Construction
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• v.16 no.2 s.69
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• pp.275-284
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• 2004

The behavior of the connection for beam-to-column weak axis connection and its details should be identified. Thus, each element is considered a panel zone, and the horizontal stiffener's presence or absence and position in bracket-type welding connection are used as variables to compare the behavior of strong axis connection and weak axis connection. In this study, the strength of connection is calculated by substituting the simple beam-strengthened vertical stiffeners for connection in the presence of horizontal stiffeners. In the absence of horizontal stiffeners, the strength of connection can be calculated using local flange bending strength considering local web yielding strength, web crippling, and web buckling strength. The results of the theoretical analysis and experiments are compared.

• Journal of Korean Society of Steel Construction
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• v.13 no.4
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• pp.419-431
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• 2001

This study was to investigate structural behavior of composite structure beams composed of end-RC. center-Steel according to respective reinforcing method for connection zone composed of different materials (SRC) while attaching main bars on steel-flange by welding. The main reinforcing methods are as follows ; non-reinforcing, vertical shear reinforcing (type-stirrup), inclined reinforcing(type-x), horizontal reinforcing(type-web, 0.3L), double horizontal reinforcing (type-web, 0.3L), vertical reinforcing (type-flange, 0.3L). Consequently, It showed little difference in structural properties like ductility and strength according to the attaching method of main bars. For Maximizing the structural properties of composite beam, the most effective methods were vertical reinforcing one and double horizontal reinforcing one.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.10a
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• pp.179-184
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• 1992

Four 3-story 1/2 scaled large concrete panel structures were designed and tested to estimate the seismic resistance capacity of large concrete panel high rise building systems, Test specimens were modeled three story of 24 or 15 story buildings and set up to represent the actural stress of the building . The axial force was constant and the horizontal force was loaded by ductility ratio. Results indicated that the joints of specimens were behavied monolithically to maximum strength. It was shown that the joint box connecting system had lower maximum strength and energy dissipation capacity than welding connection system, but had better deformation capacity.

• Journal of the Korean Society of Safety
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• v.7 no.4
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• pp.63-71
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• 1992

Generally, Web & Flange of I shape beam are composed of plane for optimization of measurement in investigating the behavior resistant to horizontal force and bending moment on large section Therefore, longitudinally traperzoidal web section beam has an important function as a body for carrying more load and ensuring more support area. There is only a limited usefulness for analyzing the behavior of web section with opening. It is experimentally verified that this traperzoidal web section has a good resistant caopacity. conclustions on the above research results are as follows : 1) resistant capacity on the above can be more 15% increased than normal case 2) stiffener welding work and complexity of shopdrawing can be excluded in advance 3) traperzoidal section can be applied in structural practice.

• Nuclear Engineering and Technology
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• v.38 no.5
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• pp.455-458
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• 2006

The HANARO reactor has a vertical hole for a cold neutron source (CNS) in the heavy-water reflector tank, i.e., the CNS hole, which was considerably deformed during its welding to the horizontal cold neutron (CN) beam tube. This paper presents an investigation of the form of the CNS hole for the optimal design of the a vacuum chamber for the CNS. In addition, the installation method of the vacuum chamber into the CNS hole for minimizing the water thickness between the vacuum chamber and the nose of the CN beam tube is proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.3
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• pp.261-268
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• 1999

The seismic performance of precast concrete panel structures tested previously has been evaluated in this paper. Hysteretic curves of test specimens are idealized to elasto-plastic curves to get reliable yielding and ultimate displacements. For the idealized curves, ductility and energy dissipation capacity of specimens have been evaluated using a few guide lines. In addition, the strength capacity of specimens is checked for the strength demand caused by the design earthquake load including overturning moment effects. The result shows while the strength of specimen with joint box for vertical continuity is little bit lower than that of specimen connected by welding, the ductility of the former is higher than that of the latter. The energy dissipation ratios of PC specimens are ranged from 83% to 96% of that of Re specimen and the average of those are shown 90%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.4
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• pp.415-421
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• 2015

This paper describes the study of the design procedure for the step-by-step setup parameters and of the magnetizing method for performance and size reduction in the development of a haptic vibrator. The study of magnetization was accomplished by comparing the electromagnetic force in accordance with the horizontal and the vertical magnetization. The theoretical results indicated that the horizontal magnetization resulted in a better performance. The systematic design of a step-by-step procedure for establishing the design parameters was verified by testing the characteristics of the fabricated prototype product. The vibration response function analysis and electric field analysis were processed by decoupling of the analytical method, and these were determined to be in good agreement with the test results. The design parameters to contributing to the product reliability included the spring height, the welding position, and the coil position. The sensitivity of the electromagnetic field and the performance change were analyzed based on the design parameters. As a result, we proposed a design method to implement a reliability-based, high performance haptic vibrator.

• Journal of Korean Society of Steel Construction
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• v.24 no.1
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• pp.73-80
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• 2012

The adoption of a composite beam system is regarded as a simple but effective solution because it improves the overall stiffness, strength and stability of the structure by welding shear studs. However, welding shear studs poses problems including electric shock and weld defects. Mechanical methods have emerged as an alternative to metallurgical methods for connecting the H-beam and shear connector. Four specimens were tested in order to compare the structural behavior of the proposed composite beams with that of the classical composite beam given the condition of horizontal loading. With the original composite beam (FCB-SB specimen) using stud bolts, hysteresis loops are stable, but its strength decreased with the crashing of the concrete slab around the column. The suggested composite beams using shear connectors also yielded stable hysteresis loops. Consequently, use of the suggested composite beams instead of the original composite beam are recommended.