Recent technical trend on telerobotics, teleoperations and telepresence for Mars rover as well as Miniature Thermal Emission Spectrometer etc. for Mars rock analysis by Rover are introduced and investigated. Scientific informations on telerobotics, teleoperations and telepresence are analysed. Researches on telepresence and telerobotics are promoted together with research on teleoperations. Derivative effect and innovation opportunity are created through space exploration technology and sustaining development of national technology are maintained.
In this study, we were turning STD11 and was carried out to presume for mutual relation of turning condition to get optimum cutting force(principal, radial, feed force) and experimental equation by variance, correlation coefficient and multi regression analysis with whisker reinforced ceramic tool. To predict cutting force, analyze principal, radial, feed force with multi-regression analysis. Results are follows: From the analysis of variance, affected factor to cutting force feed rate, depth of cut, cutting speed in order and cutting speed was very small affect to cutting force. From multi-regression analysis, we extracted regression equation and the coefficient of determination(R2) was 0.84, 0.88, 0.7 at principal, radial and tangential force. It means regression equation is significant. From the experimental verification, it was confirmed that princial, radial and tangential force was predictable by regression equation. Through the analysis of the correlation coefficient between each component forces and surface roughness, the principal force was found to have the greatest impact
In this research, the heat and flow analysis in a condenser of vehicle HVAC system was investigated numerically regarding the different shapes of the condenser tube. The velocity, pressure, and temperature distribution of the test fluid(R-134A) inside the tube were numerically calculated for the optimum design of the condenser tube for two different length with four different inlet velocities. In addition, the local pressure and temperature distributions for total tube length were calculated and the variation of pressure drop of the R-134A with flow rate were also calculated numerically. The tube at case 1 with less curved elbows was determined for the better design than case 2 in the aspect of energy-effective shape of the condenser tube.
In this study, the effect of interface friction coefficient about interfacial crack of bimaterials are discussed. The fracture parameters are analyzed by finite element method using ANSYS. With increasing the interface friction coefficient, normal crack opening displacements and normal stress distributions are analyzed. In this case with surface contact in interface crack, the energy release rates decreases with interface friction coefficient increasing. Increase in the friction coefficient of the crack surface are tend to suppressing for the initiation of interfacial crack. In this case with surface non-contact, the energy release rates are constant with interface friction coefficient increasing, and so the friction coefficient are not related with the fracture parameter.
The purpose of this study is to investigate the actual field application of the airless paint spraying pump driven by the hydraulic power unit under high pressure condition. The velocity and the pressure distributions are obtained using the turbulent k-ε model. The flow characteristics under design condition of spraying pump was numerically conducted by commercial fluid dynamic code(CFX ver. 13). The numerical analysis was performed by transient technique according to the variation of stroke times, which is changing from 0 to 1 seconds by interval of 0.01. Turbulence model, k-ω SST was selected to quaranty more accurate prediction of oil flow. The ICEM-CFD 13 and CFXMesher, reliable grid generation software were also adapted to secure high quality grid necessary for the reliable analysis. According to the simulation results, the flow rate was supplied to the paint spraying pump is 5l/min. These results are in good agreement with design results and could be applied to the design of the high viscosity paint spraying pump.
The purpose of this study is to determine more variables in welding characteristics of ATOS(Steel for Automobile Structure) 80 high tensile steel available in market, and examine how welding characteristics of ATOS 80 vary depending on changes in improvement angle of welding sections. In regard to major characteristics of this study, it focused on analyzing welding characteristics of ATOS 80 by changing improvement angle of welding sections into 40°, 50° and 60° and by changing root gap into 2㎜ and 3㎜. And it also used radiograph test to examine observations of major defects on welding section.
This study is concerned about the optimal design of the main frame in a moper. Mopper is widely used for cleaning in the fields such as airport, subway, train station, large shopping mall, department store, hospital, government buildings, school, industrial building floor, etc. Especially, main frame in mopper are stressed by high, mostly loads. Nevertheless, design of main frame is dependent on experience, and it will cause reliability reduction and cost increase. This research purpose is to propose and verify a method to achieve higher product quality, lower costs, and far less physical testing. In this study, design parameters used for optimization are each thickness of 4 square pipes and 1 plate in the main frame. The result after optimization showed that the weight of main frame reduced to maximum 6.5% when compared with the initial design in main frame.
This study aims to evaluate structural safety through FEM on the hollow shaft and the shaft filled with aluminum foam as the impact beam made of high tensile strength steel, Force reactions of impact beams are investigated when the forced displacement of 50mm is applied equally on two beams. When impact velocity of 80km/h is applied onto impact beams equally with the limit velocity of automobile on national road, how much impact energies can be absorbed by beams are also investigated. As study result, impact beams without aluminum foam and with aluminum foam show the maximum reaction forces of 15.53kN and 20.34kN respectively in case of the forced displacement of 50mm. As impact analysis result, impact beams without aluminum foam and with aluminum foam can absorb impact energies of 560J and 820J respectively. As impact beam with aluminum foam has reaction force and impact energy more than 23% and 30% than without aluminum foam, impact beam with aluminum foam has more safety than without aluminum foam.
A cooling system that applies impinging jet is studied. To create a jet, a square edge type nozzle is used as its shape. The impinging jet that composes a cooling system which applies impinging jet is created in the nozzle plate that correspond to each LED where the cooling area exists. The distance(d) between the nozzle plate and LED plate with heat sink is where the LED light is established. The main variation and the standard is examined for four different cases through the way out diameter of nozzle plate exit(D). The examined velocity distribution and temperature distribution about the impinging jet cooling system consisted of nozzle plate. It was found that an individual LED consisting of nozzle plate was efficient.
The purpose of this study is to determine more variables in welding characteristics of ATOS(steel for automobile structure) 80 high tensile steel available in market, and in terms of welding using GMAW(gas metal arc welding), this study seeks to examine how welding characteristics of ATOS 80 may vary depending on protrusion length of wire electrode. The major characteristics of this study can be summed up as follows, this study analyzed welding characteristics of ATOS 80 by changing the protrusion length of wire electrode (10㎜, 15㎜ and 20㎜) in welding section, and also used visual inspection and radiograph test to examine observations of major defects on welding section.
In this study, simulation analyses on the impact property of aluminum foam are carried and verified by experimental results. When aluminum foams with thicknesses of 25mm and 35mm are applied by impact energy of 14J, impact energy and deformation happened at aluminum foam are investigated by comparing experimental and analysis results. Experimental and analysis results of deformations or absorbed impact energy become similar each other. After verifying these simulation results with experimental results, impact properties of aluminum foams with thicknesses of 45mm and 55mm are also investigated by simulation results. As impact properties of aluminum foam can be studied effectively through only simulation results, it is thought to spare much time and cost by investigating various impact properties of aluminum foams with simulation analysis.
In this study, we have modeled a ship or marine structure into a rectangular resistance body and tried to examine surrounding flow characteristics and pressure distributions behind the resistance body experimentally and investigated pressure characteristics by a 3-dimension numerical simulation. As a result, the numerical simulation predictions were shown to compare well with PIV data. and the perpendicular velocity component behind x/H=0 varies in size with the recycle flow shapes formed from the influence of the resistance body, but generally it shows a negative distribution and there is a decreasing pattern as it goes to the down part.
Biodiesel is an alternative fuel of petroleum and has an effect on reducing smoke because that contains oxygen itself. This study shows the results on the durability of diesel engine with 4% biodiesel and WDP 1% as an alternative fuel during 110 hours. Engine dynamometer testing was complete at regularly scheduled intervals to monitor the engine performance an exhaust emissions. Through this experimental result, there was no clogging of the nozzle tip, and there was not carbon deposit on the injector tip. And, there was no unusual deterioration of the engine, or any unusual change in exhaust emission from using the blending fuel.
In this study, We have taken LED lamps which are widely used recently, applied it to training ship's cabin and lounge, cafeteria, engine control room and analyzed the power consumption and illumination with existing fluorescent. Replacing 40W, 20W of fluorescents with 22W, 11W of same number of LED lamps, It showed 45% of power consumption savings and resulted to more than 20% of illumination improvement. If applied to all areas of the ship, It would surely contribute to great amount of energy savings and illumination improvement.
In this study, we modeled a actual shape of a plate heat exchanger into triangular grooved channel and tried to examine flow characteristics experimentally by particle image velocimetry. Five Reynolds numbers were selected with the height of grooved channel and sectional mean velocity of inlet flow. As a result, the triangular grooved channel had a compound flow consisting of the flow in lower channel and the groove flow receiving shear stress by the channel flow. The sheared mixing layer, in the boundary between the triangular groove and the channel, affected main flow to raise turbulent in the channel.
The gas flow and heat transfer inside an EGR cooler for a diesel engine are numerically analyzed to investigate the performance of EGR cooler. The commercial code FLUENT is utilized to simulate a single spiral tube with constant wall temperature condition. The numerical analysis is performed with the variation of exhaust gas flow rates according to engine speed. The computational results agree well with the experimental results published before. The results show that the maximum error rate is about 0.6% for all operating conditions. Thus a single tube model with constant wall temperature condition is appropriate for simulating EGR cooler.
The paper describes variable circuits technique the enable of differential circuit of charge pump. It is able to pump an input voltage of 2V to measure several output voltage through several clock signal with each pumping capacitor of 1 pF and smoothing capacitor of 1 pF at the output. From the simulation result, it is evident that charge pump circuits offer verity high voltage pumping gain. The circuits which are implemented in this paper is simulated with LT SPICE tool of computer.
The belt in the tire components is the special cord between tread and carcass. The belt, which is compose of some steel cord and thin rubber layer, prevent to propagate the crack or external damage from tread and the separation of rubber layer and carcass. The change of belt part such as the density of steel cord, the cutting angle of cord influences on tire performance. In this study, the density of steel cord and the cutting angle of cord are changed and investigated the static/dynamic characteristics(vertical / lateral stiffness, contact length / width / area, harshness) and noise.
This paper presents the theoretical analysis for the flow driven by surface tension and gravity force in an inclined circular tube. The governing equation is developed to describe the displacement of a Newtonian fluid that continuously flew into a circular tube by surface tension, which represents a second-order, nonlinear, nonhomogeneous and ordinary differencial form. It was found that the theoretical predictions of the governing equation were excellent agreement with the unsteady state solutions for horizontal tube and the results of force balance equation for steady state.
In the car speaker, because the sound characteristics is changed by the space of car which mount the speaker, the speaker elements must be decide according to sound field. In this study, the mass of cone paper and damper is changed and the characteristics of the sound pressure and loudness are investigated by the experimental approach. According to the change of the speaker characteristics, the sound pressure and loudness level are changed. The effect of the con paper is larger than that of the damper in the aspect of the loudness. In the future, these data will be used to investigate the correlation between the sound quality and measurement data.