• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.523-524
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• 2008

• Earthquakes and Structures
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• v.19 no.5
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• pp.315-329
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• 2020

Through bolt connections in Concrete Filled Steel Tubes (CFSTs) has been proved to be good in terms of seismic performance and constructability. Stiffened extended end plate connection with full through type bolt helps to avoid field weld altogether, and hence to improve the quality of joints. An experimental study was conducted on the hysteretic performance of square interior beam-column connections using flat extended end plates with through bolt. The study focuses on the effect of the bond between the tie rod and the core concrete on the cyclic performance of the joint. The study also quantifies how much the interior joint is getting strengthened due to the confinement effect induced by bi-directional bolting, which is widely used in 3D moment resisting frames. For a better understanding of the mechanism and for the prediction of shear capacity of the panel zone, a mathematical model was generated. The various parameters included in the model are the influence of axial load, amount of prestress induced by bolt tightening, anchorage, and the concrete strut action. The study investigates the strength, stiffness, ductility, and energy dissipation characteristics. The results indicate that the seismic resistance is at par with American Institute of Steel Construction (AISC) seismic recommendations. The bidirectional bolting and bond effect have got remarkable influence on the performance of joints.

• Journal of Korean Association for Spatial Structures
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• v.23 no.4
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• pp.97-105
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• 2023

The membrane structure should maintain the membrane materials in tension for structural stability guaranty. The anchoring part in the membrane structure is an important part. It has the function to introduce tension into membrane materials and function to transmit stress which membrane materials receives to boundary structure such as steel frames. In this paper, it grasps anchoring system of the anchoring part in the membrane structure concerning the fracturing characteristic condition of membrane structure, and the influence which is caused to yield it designates the stress state when breaking the membrane structure which includes the anchoring part and that stress transition mechanism is elucidated as purpose. This paper follows to previous paper, does 1 axial tensile test concerning the bolting part specimen, grasp of fracturing progress of the bolting part and the edge rope and hardness of the rubber, does the appraisal in addition with the difference of bolt tightening torque. As a result, the influence which the bolt anchoring exerts on the fracturing characteristics of the membrane material in the membrane structure anchoring part is examined.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.31-37
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• 2011

Construction automation is yet to be improved since construction site still faces a lot of high risks and difficulties. This research focuses on applying robotic beam assembly system in place of construction workers. This system consists of CF (Construction Factory) structure to provide adequate working environment to robot automation. The CF structure not only gives automation environment for a robot but also houses the equipments to protect from outside effects. The robotic beam assembly system also consists of robotic bolting system and robot transport mechanism. It utilizes various tools to insert and join the bolts and nuts. Visual servoing helps precise robot motion by sensing bolt hole and tail of the bolt. ITA system helps non skilled workers to easily perform the assembly work with the robot system. The robot transport mechanism includes sliding rail and cross-wired lift. It carries the robot to a desired position for assembly work.

• Korean Journal of Medicinal Crop Science
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• v.20 no.5
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• pp.359-364
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• 2012

This study were carried out to find bolting response of cultivation in different regions and to isolate FLC (FLOWERING LOCUS C) homologs in Angelica gigas Nakai. The mean temperature of different regions, ordering in altitude, were as follows: 100 m > 350 m > 530 m > 700 m. The largest amount of rainfall was occurred in the region of 350 m while the longest time of sunshine was occurred in the region of 100 m. The content of soil chemical properties in regions showed pH 6.2 ~ 7.4, T-N 0.17 ~ 26, organic mater $1{\sim}32gkg^{-1}$, $P_2O_5$ ${151{\sim}664_{mgkg}}^{-1}$, exchangeable potassium and calcium and magnesium were 0.78 ~ 1.15, 3.9 ~ 10.0, ${0.7{\sim}3.2_{cmol}}^{+kg-1}$. L5 line of A. gigas was occurred in bolting at all regions, but the bolting ratio was 60.0% in 700 m region with non-mulching treatment. Manchu of A. gigas was not occurred in bolting at all regions. The accumulation bolting ratio of L5 line by non-mulching was higher than that of mulching as 90.4% and 72.8% in 100 m region. The MADS-box transcription factor FLC is one of the well-known examples as a strong floral repressor. We decided to isolate FLC homologs from A. gigas as a starting point of flowering mechanism research of this plant. We have isolated two RT-PCR products which showed very high amino acid sequence homology to Arabidopsis FLC.

• Journal of the Korean Society for Heat Treatment
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• v.20 no.4
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• pp.195-202
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• 2007

Corrosion resistance and torque of M10 bolt coated with Magni 565 were investigated. Corrosion protection mechanism were also studied with the microstructure of coating film. The bolts with the optimum conditions showed around $10{\mu}m$ layer thickness, a great corrosion resistance in salt spray test and a proper torque in torque/tension test. But torque coefficient k increased with the number of bolting and clamping force of M10 bolt showed significantly lower than that of specified value 28.3kN. It was thought that the repeated bolting made the coating film peel off and powdery. The sample coated with optimum coating conditions showed more higher polarization resistance and corrosion potential than the specimens of top and base coat only. The base coating film was composed of lamellar zinc flakes, which provides a large sacrificial cathodic protection. Meanwhile, the top coating film was composed of organic aluminium pigments layer, which provides barrier protection to the corrosion circumstances.

• Journal of the Korean Society for Nondestructive Testing
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• v.9 no.1
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• pp.106-110
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• 1989

Bolting degradation problems in primary coolant pressure boundary applications have become a major concern in the nuclear industry. In the bolts concerned, the failure mechanism was either corrosion wastage(loss of bolt diameter) or stress-corrosion cracking.(3) Here the manual ultrasonic testing of RPV(Reactor Pressure Vessel) and RCP(Reactor Coolant Pump) stud has been performed. But it is difficult to detect indications because examiner can not exactly control the rotation angle and can not distinguish the indication from signals of bolt. In many cases, the critical sizes of damage depth are very small(1-2 mm order). At critical size, the crack tends to propagatecompletly through the bolt under stress, Resulting in total fracture.(3) Automatic stud scanner for studs(bolts) was developed because the precise measurement of bolt diameter is required in this circumstance. By use of this scanner, the rotation angle of probe was exactly controlled and the exposure time of radiations was reduced.

• Tunnel and Underground Space
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• v.20 no.4
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• pp.267-276
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• 2010

In modern rock engineering practice, fully grouted rock bolting is actively employed as a major supporting system, so that understanding the behavior of fully grouted rock bolts is essential for the precise design of rock bolting. Despite its importance, the supporting mechanism of rock bolts has not been fully understood yet. Since most of existing analytical models for rock bolts were developed by drastically simplifying their boundary conditions, they are not suitable for the bolts of in-situ condition. In this study, 3-D elastic FE analysis of fully grouted rock bolts has been conducted to provide insight into the supporting mechanism of the bolt. The distribution of shear and axial stresses along the bolt are investigated with the consideration of different boundary conditions including three different displacement boundary conditions at the bolt head, the presence of intersecting rock joints, and the variation of elastic modulus of adjacent rock. The numerical result reveals that installation of the faceplate at the bolt head plays an important role in mobilizing the supporting action and enhancing the supporting capabilities of the fully grouted rock bolts.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.5
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• pp.69-82
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• 1992

Vibration of intake menifold is important as it could worsen the noise levels radiated from surface itself and support bracket, and it eventually leads to the failures of a Throttle Position Sensor and an Idle Air Control Valve. In this study, structural modification method is proposed to reduce structural vibration of an intake manifold system. At first, vibration problems are identified through tests on a running engine. Then modal data acquired by modal testing and finite element analysis are helpful to understand vibration mechanism of the system, and used as the design guide when structural modifications are attempted. After the system model is validated by comparison of the modal data obtained from analysis and experiment, iterative calculations are performed to find optimized structure of the system by finite element analysis. As a result, a newly designed plenum bracket is suggested in such a way that the intake manifold is stiffened, and that design of the support bracket is suggested in such a way that the intake manifold is stiffened, and that design of the support bracket is changed in terms of bolting position, thickness, shape, and minimum weight increase. Finally, it is shown that a new design achieves a significant reduction of vibration of an intake manifold system and it is confirmed by tests on a running engine.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.1
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• pp.51-61
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• 2005

In general the strength parameter of the ground will be changed by reinforcing the ground around tunnel. In this case, the concept of tunnel design, such as supporting system, excavation, lining and so on, should be modified based on the failure criteria or the ground changed by the reinforcement. This paper presents the variation mechanism of strength parameters and new failure criteria of the reinforced ground. In order to perform this research, theoretical and experimental works were carried out. It was clearly founded that the cohesion of strength parameters is only increased by reinforcement of ground, especially by rock bolting.