• Journal of Korean Society of Steel Construction
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• v.9 no.2 s.31
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• pp.171-179
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• 1997

The high-tension bolted joints are clamped by the axial force which approaches the yielding strength. The introduced axial force is transmitted to the connection members pass through washer. The transferred load in connections is balanced to the compressive stress of plates, axial force in bolts and the external loads. In this mechanism, the compressive stress and slip load we dominated by the effective stiffness of bolted joints and plates. In general the effective stiffness is specified to product to the effective area and elasticity modulus in connections. In this reason, the conic projection formular which is assumed that the axial force in bolts is distributed to the cone shape and that region is related to the elastic deformation mechanism in connections, was proposed. But it conclude what kind of formula is justified. Therefore in this paper, the fatigue tests are performed to the high tension bolted joints and inspected to the phase on the friction face. And using the FEM and numerical method, it is analyzed and approximated to the compressive stress distribution and its region. Moreover, it is estimated to the effective area and to the relation the friction area to the effective compressive distribution region.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.607-615
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• 2016

This study concerns the transmission of energy and data using induced electromotive force. Due to the requirements of weapon systems, most arms are kept in an armory for a very long time before being used. During this time, the reserve battery, which serves mostly as a power supply for the electronic fuze, can be degraded, thus causing problems when it is actually needed. We attempt to solve the various problems associated with the old fuze system caused by long-term storage by using the 'induction power' transmitted from another device just before its operation, instead of using 'built-in power'. We tried to find the best carrier frequency to communicate with the system by induced electromotive force. Also, we changed the communication method for transmitting the 'induction power' from 'FM/AM modulation' to 'Duty ratio modulation', which can transmit a large amount of data in a short time. Through experiments, it was demonstrated that the induction coil can replace the reserve fuze's battery without any problem, thus confirming the possibility of using an induction coil as the power supply source of the electronic fuze.

• Structural Engineering and Mechanics
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• v.73 no.2
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• pp.143-152
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• 2020

Deep coupling beams are more prone to suffer brittle shear failure. The addition of steel fibers to seismic members such as coupling beams can improve their shear performance and ductility. Based on the test results of steel fiber reinforced concrete(SFRC) coupling beams with span-to-depth ratio between 1.5 and 2.5 under lateral reverse cyclic load, the shear mechanism were analyzed by using strut-and-tie model theory, and the effects of the span-to-depth ratio, compressive strength and volume fraction of steel fiber on shear strengths were also discussed. A simplified calculation method to predict the shear capacity of SFRC deep coupling beams was proposed. The results show that the shear force is mainly transmitted by a strut-and-tie mechanism composed of three types of inclined concrete struts, vertical reinforcement ties and nodes. The influence of span-to-depth ratio on shear capacity is mainly due to the change of inclination angle of main inclined struts. The increasing of concrete compressive strength or volume fraction of steel fiber can improve the shear capacity of SFRC deep coupling beams mainly by enhancing the bearing capacity of compressive struts or tensile strength of the vertical tie. The proposed calculation method is verified using experimental data, and comparative results show that the prediction values agree well with the test ones.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.648-655
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• 2005

The resilient mounts of a diesel engine installed onboard a ship should be designed for both static and dynamic loads. If possible, the resonance frequencies of the six rigid body modes of the installation and the flexible modes of the engine support structure should not lie within the engine operation range. In this paper a design criterion is proposed to evaluate an isolation system which involves the summation of dynamic forces transmitted through the resilient mounts and elastic potential energy index stored in the mounts. A case study is also presented in which a diesel engine generator, which had an elastic foundation and was mounted in a 5500 TEU container vessel, was studied both theoretically and experimentally. The theoretical analysis of the test model was performed by using a single mass 6 degree of freedom system. Actual measurements of mechanical vibration of the Engine and its foundation onboard were carried out, which showed the importance of including the flexibility of the engine support structure in the mode

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.4
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• pp.386-392
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• 2008

This paper presents active vibration control performance of a hybrid mount. The proposed hybrid mount is devised by adopting both piezostack as an active actuator and rubber as a passive element. After experimentally identifying actuating force characteristics of the piezostack and dynamic characteristics of the rubber, the hybrid mount was designed and manufactured. Subsequently, a vibration control system with a specific mass loading is constructed, and its governing equations of motion are derived. In order to actively attenuate vibration transmitted from the base, a feedforward controller is formulated and experimentally realized. Vibration control responses are then evaluated in time and frequency domains.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.171-178
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• 1997

Vehicle interior noise has become increasingly important in this recent years. The noise of a vehicle is one of the important problems in a vehicle design. The interior noise is caused by various vibration sources of vehicle compartment. The booming noise of a vehicle can be significantly affected by vibrations transmitted from engine excitation forces to the vehicle body. Specially, we are interested in the state of transmission paths such as engine mounts to reduce noise in a vehicle compartment. In this paper, we have been calculated the contribution of each transmission path such as engine mounts to interior noise. To identify contribution of each input sources and transmission paths to output, the effectiveness of each input component to output is calculated. Sensitivity analysis is carried out for investigation of contribution to output due to input variations. With the simulation of magnitude and phase change of inputs using vector synthesis diagram, the trends of synthesized output vector are obtained. As a result, we suggested sensitivity analysis of vector synthesis as a technique of prediction and control for noise in a vehicle compartment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.12
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• pp.1059-1068
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• 2017

Space exploration spacecraft carry large amounts of liquid fuel, often more than half. In such cases, the liquid fuel sloshing must be considered in the design of the spacecraft since the sloshing can affects the stability of the spacecraft. In this paper, we present the results of analyzing the sloshing of fuel and the dynamic behavior of the spacecraft. For the purpose, a model in which the maneuvering of the spacecraft causes the sloshing and a model in which the reaction force and moment due to the sloshing are transmitted to the spacecraft are developed. The dynamical behavior of the spacecraft are analyzed using a simulation program coded by Modelica.

• Bulletin of the Society of Naval Architects of Korea
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• v.3 no.1
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• pp.19-24
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• 1966

The maximum shear stress distribution in a stiffening flat attached to a plat undergoing a single tensile force has been investigated by photoelastic method. In the experiments a photoelastic model, as shown in Fig. 1, has been studied in the fields of a polariscope, as shown in Fig. 2. Fig. 3 shows the isoclinics and Fig. 4 and 5 are stress trajectories of the principal stresses and maximum shear stresses, respectively. Fig. 6 is the isochromatics in light field. The maximum shear stress at each point in the stiffener were determined from the isochromatics in both of light field of light field and dark field. Then the maximum shear stresses were divided by the average shear stress in the model, to obtain the ratio ${\tau}max/{\tau}av$ at each point. Finaly the variations of the ratio ${\tau}max/{\tau}av$ along the horizontal and vertical lines in the stiffener have been plotted, as shown in Fig. 7 and 8. The conclusions reached in this investigation are as follows: (1) The shear stresses transmitted to the stiffener through the juncture are concentrated on the end portions. (2) The maximum shear stress at the ends of the stiffener reaches to about 4 times of average shear stress. (3) The irregularities in the stress distribution are restricted in the end portions of the stiffener.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.57-61
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• 2005

This paper presents a new colonoscopy training simulator that includes a specialized haptic device and graphics algorithms to transfer haptic sensation through a long and flexible tube, and manage large number of polygons. The developed haptic device makes the colonoscope tube move along the two guiding rods in the translational direction. The torque of the roll motion is transferred by a timing belt and pulleys. A special guide is developed, which allows the force and torque from the motors to be transmitted to the user without loss. The haptic device is evaluated by physicians. One of the important skills of the colonoscopy, jiggling is incorporated for the first time by the developed sensor mechanism using photo-sensors. A colonoscope handle that shares the look, feel, and functions with the actual colonoscope, is developed with the necessary electronics inside. The number of polygons is reduced by an edge-collapse algorithm for real-time simulation. The algorithms to import CT data, to segment the colon image, to extract centerline of the colon, and to construct the colon surface, are integrated into a Colon Modeling Kit system that performs all these processes in real-time.

• The korean journal of orthodontics
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• v.21 no.1 s.33
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• pp.31-51
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• 1991

This study was designed to survey the stress distributions and deflections which were derived from MEAW by the computer-aided three dimensional finite element analysis of teeth and surrounding bone composed of 2839 solid elements and 4621 nodes. MEAW model was also made using the 90 beam elements and the results were expressed by quantitative and visible ways. The findings of this study were as follows. 1 In case of vertical load on the MEAW there were extrusions of anterior teeth and upright effects of the posterior teeth. 2. Without applying the vertical elastics on the MEAW there were intrusions of anterior teeth, but relatively mild force was transmitted to the posterior teeth area. Torque forces were observed on the incisors and molars, and canine was intruded without torque. 3. The magnitudes of forces were different by the amounts of tip back bends of MEAW. 4. The displacements were in inverse proportion to the cross section areas of the wires according to the experiment using the 5 different size arch wires. 5. The difference of deflections between the MEAW and plain arch wire was not so big as the theoretical one but the deflections of MEAW were much more than the plain arch wire in every X, Y, Z direction.