• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.3 s.234
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• pp.295-305
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• 2005

To improve the aerodynamic effciency of TR-E2, a new configuration so called TR-E2Sl was introduced. TR-2251 is composed of different wing airfoil section and T-tail shape compared with TR-E2. Wind tunnel test for TR-EBS1 had been performed by changing the incidence angles of wing and deflection angles of control surfaces such as elevator and rudder. Also the on/off effect of ventral fin attached underneath of AFT fuselage was tested. Test result showed that variations of wing incidence angle did not cause any severe differences in aerodynamic characteristics. Longitudinal and directional characteristics of TR-E2S1 show stable for the pitch and yaw motions. However, the lateral stability of TR-E2S1 is not stable for a certain control surface deflection.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.5
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• pp.1-9
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• 1995

The purpose of this study is to develop a computer simulation program for analyzing load transmission characteristics of a helical gear system in design stage. In this analysis, the rotational delay, load distribution, root stress, and contact area are investigated. That is, the influence function of deflection is obtained by finite element analysis and the influence function of approach and gear tooth error are considered. Load distribution, rotational delay, and contact area are calculated by solving load-deflection equation which includes these influence functions and tooth error, and the influence function of the bending moment is obtained by finite element analysis. The root stress is calculated by the load distribution and the influence function of the bending moment. The results of the simulation are cross-checked through a specially designed experimental set-up.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.130-131
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• 2019

As part of recent low-energy policies, thermal insulation standards for buildings are being tightened every year. In addition, the conventional styrofoam insulating material has a problem that the thickness of the heat insulating material to achieve a standard heat permeability is rapidly increased. Due to the thick insulation, there is a high risk of spreading vulnerable structures such as fire due to lack of space between buildings. On the other hand, the method of using the insulation as a formwork is known to be excellent cost saving effect through the reduction of the formwork usage and the simplification of the external insulation work. In order to solve this problem, this study aims to fabricate a multi-layered insulator that combines high-performance phenolic foam insulation and styrofoam insulation and evaluate the deflection characteristics for use as formwork.

• Structural Engineering and Mechanics
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• v.89 no.1
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• pp.47-59
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• 2024

In this study, a new sustainable material was proposed to prepare precast tunnel lining segments (TLS), which were produced using a fiber-reinforced slag-based geopolymer composite. Slag was used as the geopolymer binder. In addition, polypropylene and carbon fibers were added to reinforce TLSs. TLSs were examined in terms of flexural performance, load-deflection response, ductility, toughness, crack characteristics, and tunnel boring machine (TBM) thrust force. Simultaneously, numerical simulation was performed using finite element analysis. The mechanical characteristics of the geopolymer composite with a fiber content of 1% were used. The results demonstrated that the flexural performance and load-deflection response of the precast TLSs were satisfactory. Furthermore, the numerical results were capable of predicting and realistically capturing the structural behavior of precast TLSs. Therefore, fiber-reinforced slag-based geopolymer composites can be applied as precast TLSs.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.543-549
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• 2014

The deflection of reinforced concrete members can be highly variable, due to uncertainties in the characteristics of the concrete. However, current standards do not take this problem into account, instead recommending only the minimum thickness and maximum allowable deflections based on empirical data. This paper is aimed at evaluation deflection variabilities by applying a probabilistic analysis model to a finite element analysis model. To evaluate the variabilities of deflections, a Monte Carlo simulation, which incorporated the eight parameters related to concrete, reinforcement, member size, and tension stiffening. The results showed that lager spans were more sensitive to the deflection due to loads and that as the applied live loads were increases and the slab thickness were decreased, the deflection variability increased.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.12a
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• pp.30-37
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• 1999

• Fire Science and Engineering
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• v.17 no.2
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• pp.25-34
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• 2003

In this paper, characteristics of the DC flashover voltage in the horizontal air gap of sphere-sphere/needle-needle electrode system were investigated when the combustion flame of paraffin oil was present between the two electrodes. The reduction characteristic of DC flashover voltage was discussed with the thermal ionization process, the relative air density and the deflection phenomena in the shape of flames that caused by the corona wind and Coulomb's force. As the results of an experimental investigation, It was found that the reduction characteristics of DC flashover voltages with flames were affected strongly by the flame deflection and the change of relative air density. It was also found that the thermal ionization phenomena were not important in the range of combustion flame temperature.

• Elastomers and Composites
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• v.16 no.1
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• pp.3-13
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• 1981

The purpose of this dissertation is to study the physical properties of cellular rubber products for industrial use. Vulcanization characteristics were investigated by usingcure curve that had obtained by means of Rheometer. The results of physical properties, vulcanization characteristics and foaming states are as follows. 1. The test results for vulcanization characteristics of NR compounds indicated that in the recipe R-1. When accelerator D is used, the optimum conditions of vulcanizate are obtained, while formula R-2 and R-3 have shown higher torgue at curing time, $1{\sim}2$ minutes. Cellular rubber product test in terms of compression set and compression deflection has also met the requirements of SAE. 2. For SBR compounds, S-1 formula was the best in terns of vulcanization characteristics, and for the blowing structure of cellular rubber products, formula S-3 in which accelerator M is added was fair. All other test results, such as compression set and compression deflection properties met SAE requirements. 3. NBR compound (N-1) including accelerator TT was the best in terms of vulcanization characteristic and also blowing structure. All other properties listed above met requirements, particulary for oil resistance test. 4. In the test of EPDM compounds, when mixed accelerator, M and TT, is used(formula E-1) the best results were obtained. Since EPDM is hydrocarbon elastomer, oil resistance test failed. All other properties met the requirement specified in SAE.

• Journal of Sensor Science and Technology
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• v.12 no.6
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• pp.265-272
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• 2003

This paper describes anodic bonding characteristics of MLCA (Multi Layer Ceramic Actuator) to Si-wafer using evaporated Pyrex #7740 glass thin-films for MEMS applications. Pyrex #7740 glass thin-films with same properties were deposited on MLCA under optimum RF magneto conditions(Ar 100%, input power $1\;W/cm^2$). After annealing in $450^{\circ}C$ for 1 hr, the anodic bonding of MLCA and Si-wafer was successfully performed at 600 V, $400^{\circ}C$ in - 760 mmHg. Then, the MLCA/Si bonded interface and fabricated Si diaphragm deflection characteristics were analyzed through the actuation test. It is possible to control with accurate deflection of Si diaphragm according to its geometries and its maximum non-linearity is 0.05-0.08 %FS. Moreover, any damages or separation of MLCA/Si bonded interfaces do not occur during actuation test. Therefore, it is expected that anodic bonding technology of MLCA/Si wafers could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.5
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• pp.416-423
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• 2011

The purpose of this research is to investigate the operation characteristics of fluidic thrust vector control using injection of the control flow parallel to the main jet direction; Co-flow injection. The technique bases on the Coanda effect of flow. Both numerical and experimental studies were conducted to investigate operation parameters; flow structure, the jet deflection angle, and shock effects near the nozzle exit. While the total pressure of main jet is the range of 300 to 790 kPa, the total pressure of control flow varies from 120 to 200 kPa. The jet deflection angle and thrust coefficient have linear relation with the pressure ratio(PR) of main jet to control flow in 0.15 < PR < 0.4 but show their limit above PR = 0.4.