Earticle

This research is to investigate the flow characteristics of micropump with two different types of diffuser outlet in micropump (straight and round). Four different outlet diameters(1mm, 1.5mm, 2mm at straight type of diffuser outlet and single outlet diameter(1mm) at round type are utilized for the flow analysis of the diffuser in micropump. Velocity and pressure distributions of fluid over the flow domain are numerically calculated for the shape optimum design of diffuser in micropump with uniform inlet velocity and pressure. According to the calculations of local maximum pressure at diffuser outlet, straight type of diffuser with larger diameter of diffuser outlet is of highest flow energy performance of the flow channel shapes in the present micropump.

The tires changes characteristics of the element constituting change. Stiffness is one of the various characteristics of the tire. Stiffness of the tire is change contact contour. it is known to affect vibration and noise of the vehicle. In this study we conduct to find influence of change stiffness of the tire due to vibration characteristics inside passenger car. For this study we choose tires of available on the market and measure vertical spring rate and lateral spring rate. Also through the real passenger car we find vibration characteristics in the inside of car. In conclusion, vibration energy is reducing with increase in the stiffness and we find the high vibration level of low frequency band in passenger car due to decreasing stiffness.

In this paper, the forward and inverse kinematics equations for demolition fire vehicle with 6-DOF were developed. This was done through the development of an interface that allows co-simulation using MATHEMATICA and ADAMS. The implementation of this project was done entirely in MATHEMATICA by calculating the kinematics equations to demonstrate the usefulness of this product. The forward and inverse kinematics of the demolition fire vehicle represents the position and orientation of the end- effector as any desired location. This research was particularly conducted using the simulator, and it showed good approximation results in terms of solving a reaching task problem.

This study presents design, construction and testing of a immiscible two working fluids thermosyphon with water and FC-40 to prevent freezing of vehicle starting up at temperatures below freezing point of water. The two working fluids thermosyphon was experimentally investigated on the startup characteristics at low temperatures below 0°C and then the thermosyphon was stable during startup and operated reliable at temperature of –30°C. The testing also showed that the performance and characteristics of the two working fluids thermosyphon differ from the charging ratio and mixture ratio of the two working fluids.

The present experimental study investigates single-phase heat transfer coefficients downstream of support grid in 6×6 rod bundles. Support grid with Split mixing vanes enhance heat transfer in rod bundles by generating turbulence but this turbulence is confined to a short distance. Support grid with large scale vortex flow(LSVF) mixing vanes enhanced heat transfer to a longer distance. In this study, the experiments were performed at reynolds numbers of 50,000. The characteristics of the heat transfer enhancement of the Split mixing vane and those of the LSVF mixing vane were compared. The results showed that the characteristics of the heat transfer enhancement of rods by the Split mixing vane were limited to 10 Dh after the spacer grid, but those by the LSVF mixing vane were maintained until 15 Dh after the spacer grid. For the reynolds number of 50,000, the heat transfer enhancement effect was 3.0% greater when using the LSVF mixing vane than when using the Split mixing vane between the 1 ∼ 15 Dh interval after the spacer grid.

Structural system involves random conditions such as material property, geometric parameters and applied loads. This is caused by either measurement inaccuracy or system complexity and must be designed to withstand the uncertainties, Random structures may be modelled by using the finite element method using Monte Carlo simulation. It can be applied easily to any structural system with random parameters. The aim of this paper is to find the shape optimal design for the cantilever beam with random input variables to the height and response parameters to the displacement and stresses. The probabilistic design is carried out using ANSYS probabilistic design module in a commercial application software and then the optimal design is sequentially solved. An efficient and practical shape optimal design evaluation method is proposed for the design of the cantilever beam shape. The numerical results are obtained where total volume of the beam, stresses and displacements in the beam treated as constraints

This research is to numerically investigate the flow analysis of thermopneumatic micropump with three different thicknesses of PDMS membrane in micropump owing to the thermal expansion with uniform heat flux in the PDMS membrane. Velocity, temperature distributions and flow rates over the flow domain with different membrane thicknesses in the micropump are numerically calculated for the performance evaluation of pressure increase in micropump with uniform inlet velocity and temperature. According to the calculations of local maximum velocity at outlet, higher thickness of PDMS membrane(500μm) give larger local velocity in the micropump and maximum local velocity occurred at the center of the micropump with respect to the axial direction.

In this paper, the main objective is to determine the mechanical responses due to the axial forces on thrust bearing for an automotive turbocharger. The rotating shaft in a turbocharger is supported by the bearings, usually oil-lubricated radial journal bearings and a thrust bearing. The axial forces acting on the thrust bearing have significant influences on the mechanical friction losses, which reduces the efficiency and performance of high-speed turbocharger. There are simple well-known formulas such as Petroff’s equation for calculating the mechanical frictional losses in these types of bearings. However, it's difficult to estimate the accurate axial forces from this formula. Thus, this work determined the relationship between thrust forces and strains by measuring and calculating the strains on thrust bearing and compared both results. The result shown that behaviors of axial strain are changed linear and non-linear depend on the boundary condition. Therefore, it’s possible to predict the magnitudes of the axial forces by measuring the strains under operating turbocharger.

Many polymers exhibits sufficient birefringence to be used as photoelastic specimen material. Common polymers as polymethylmethacrylate (PMMA) are often used as photoelastic specimen. In a photoelastic experiment, it is necessary to know the material fringe constant of the photoelastic specimen to determine the stresses from the measured isochromatic fringe orders. The material stress fringe constant is determined using the simple tension specimen. The stress fringe constant measured with this method is applied to obtain the stress distribution in a tensile plate with a circular hole. Photoelastic results using the measured material fringe constant are compared with FEM analysis. Two results are comparable, so it can be seen for the measured material fringe constant to be valid.

In this study, the cold rolled DP590 FSW joints were obtained by the position control type of the FSW machine and examined. The FSW weldability was investigated using the Si3N4 tool specially made by Cold Isostatic Press (CIP). Defect-free joints were formed at 180-300 mm/min at 800 rpm. However, a groove-like defect was observed along the joint line of the advancing side due to the insufficient material flow. In addition, the life of the Si3N4 tool was compared to that of the polycrystalline cubic boron nitride (PCBN) tool for the durability. The SI3N4 tool that was broken in which tool reached a length of 5 m and around half of the performance level of the PCBN tool.

Pneumatic cylinder actuators are significantly utilized for industry automatic systems in the fields of mechanical applications. We propose a novel control method for pneumatic cylinder actuator systems including stochastic friction dynamics. The proposed control mechanism is linearly composed of nominal control and auxiliary control variables. The former is designed from linear system model without friction terms by using a previous linear system theory and the latter is constructed as a function of friction estimation which is carried out by a well-known least square algorithm for reducing the control error due to random friction dynamics. We accomplish numerical simulation to demonstrate reliability of the proposed control method and conduct a comparative study to improve its superiority.

This study investigates the property of crack growth at the specimen of structural steel. The behaviour of fracture mechanics on the specimens with only a center crack and with holes existed symmetrically near a center crack is studied. The tensile load is applied on the specimens with these conditions. Stress intensity factors are obtained by the basis of these experimental values and these values are verified with the structural analysis of finite element method. As the length of center crack becomes larger in case of the specimen with holes existed symmetrically near a center crack, the values of deformation energy and stress become larger. On the contrary, the values of deformation energy and stress become smaller as the length of center crack becomes larger in case of the specimen with only a center crack. By examining the stress intensity factor in this study, this value becomes rather smaller although the length of center crack becomes larger. There is the position where crack is likely to happen or weak part at the mechanical structure or the machine. As the holes are punctured and arranged adequately near this crack or weak part by using the result of this study, the fracture due to it can be prevented.

This paper develops a fishing lamp mounting system which opens or closes a mounting rack according to a fishing situation. A developing fishing lamp mounting system is designed using CAD software. Members composing the fishing lamp mounting system are modeled with finite elements based on 3D CAD model. In addition, the fishing lamp mounting system is modeled with rigid bodies. A rigid body model of the fishing lamp mounting system is interfaced with finite element component models to develop a computational model of the fishing lamp mounting system for dynamic stress analysis. This paper performs a simulation with bouncing, rolling and pitching motion which describe a very rough sea condition. This paper manufactures a fishing lamp mounting system which is designed with CAD software and analyzed dynamic stress with CAE technique.

In this study, the effect of downward inclined interface about interfacial crack of bimaterials are discussed. The fracture parameter are analyzed by finite element method of the ANSYS. The energy release rates, displacement jump and stress distribution were analyzed as the gradient variation of inclined interfaces. As a results, in case of positive shear displacement was applied, the energy release rates not varied with gradient of inclined interface increasing. However in case of negative shear displacement was applied, the energy release rates decreased with gradient of inclined interface increasing. Due to the inclined interface contact, the shielding effect relatively increased as the gradient of inclined interface was increased.

Diesel vehicle is regulated EURO 5 and will be apply to EURO 6 in 2014. Thus, researches have been performed to meet the strict emission regulations. We have obtained that the results of engine performance operated by lard biodiesel at various engine load and speed was slightly decreased, but brake specific energy consumption (BSEC) at using animal biodiesel below 15% was better than diesel fuels. When the mixing ratio of biodiesel increased, NOx was a slight increase. But PM and CO was a significantly reduced. Therefore, that the biodiesel of animal fats is available for eco-friendly fuel of diesel engine was confirmed.

CFRP composites have high specific strength, specific stiffness, long fatigue life, light weight environmental safety characteristics. In this study, the mechanical properties are investigated through the compressive simulation analysis on the carbon fiber reinforced plastic sandwich. The experiment is carried out with the same condition as the analysis to verify the analysis result. One sandwich plate is composed with four layers. From the upper, this plate has the first, second, third and fourth layers due to the arrangement of angle direction. A plate has the symbol of [0/30/30/0] as the first, second, third and fourth layers due to the angle directions of 0°, 30°, 30° and 0°. There are the plates of [0/30/30/0], [0/60/60/0] and [0/90/90/0] in this study. The maximum compressive load becomes 53.139kN during the compression time of 12 sec in case of the plate of [0/30/30/0]. The maximum compressive load becomes 61.826kN during the compression time of 12 sec in case of the plate of [0/60/60/0]. The maximum compressive load becomes 53.002kN during the compression time of 12 sec in case of the plate of [0/90/90/0]. So, the plate of [0/60/60/0] endures the most load among three plates. The result of this study can be applied practically through the validation of experimental data on the simulation data. In this study, the mechanical characteristics are examined systematically through the impact analysis on the composite material of the carbon fiber reinforced plastic with aluminum foam by using the impact absorption due to CFRP plate.

This paper studies the repulsion occurring between the permanent magnet by the simulation analysis. Nowadays, there are many cases such as magnetic levitation, safety bumper device and so on using the properties of the permanent magnet. As the neodymium magnet of the powerful ferromagnetic material is less expensive by comparing with the strong magnetic force for industrial, medical areas and etc., it can be used at the various applications. The prediction of the magnetic force is becoming increasingly important in order to be used effectively permanent magnet in various fields. Therefore, the results of the magnetostatics by Ansys and the MAXWELL of commercial electromagnetic analysis software are analyzed and compared. Magnetic force is inversely proportional to the distance and power. In this paper, the permanent magnet was simulated and compared by the two permanent magnets of the small sizes with the diameter of 4mm and the length of 8mm. In addition, the forces between the ferromagnetic iron and permanent magnets are simulated.

The study on ice thermal storage system is to improve total system performance in actual air-conditioning facilities. This paper deals with experimental research to observe the characteristics of heat flow and the effect of ice thermal storage in case of three sizes of ice ball, which are included identification of ice thermal extraction. Diameters of three ice ball was 103mm, 96mm, and 76mm is equivalent to 0.45, 0.50 and 0.55 in porosity respectively. Also inlet geometric parameters are the perforator and distributor. Flow rate of brine were 2LPM, 4LPM and 6LPM and the temperature difference in dynamic parameter are 8℃, 10℃ and 12℃. Flow rate of brine used the liter per minute(LPM) for liquid measurement applications. The effect of brine flow rate on efficiency increased as the temperature difference and porosity increased. An adaption of a long-term storage in case of smaller porosity(ɛ=0.45) was available through experiments of outlet temperature responses.

Nematic liquid crystal (NLC) alignment effects on SiOF layers via ion-beam(IB) irradiation for four types of incident energy were successfully studied. The effect of fluorine addition on silicon oxide film properties as a function of SiOF₄/O₂gas flow ration was investigated. The SiOF thin film exhibits good chemical and the thermal stability of the SiOF thin film were sustained as function of the NLC alignment until 200℃. Also, the response-time characteristics of aligned LCD based on SiOF film were studied.

This paper develops a LED fishing lamp mounting system which slides in and out a LED fishing lamp mounting rack according to fishing situation of a fishing boat. Sliding mechanism of the LED fishing lamp mounting system is realized with a rack and pinion. Components of the LED fishing lamp mounting system are modeled with finite elements. In addition, the LED fishing lamp mounting system is modeled with rigid bodies. A rigid body model of the LED fishing lamp mounting system is interfaced with finite element component models to develop a computational model of the LED fishing lamp mounting system. A simulation is performed with the developed computational model for dynamic stress analysis of the LED fishing lamp mounting system. A bouncing, rolling, and pitching motion which describe a very rough sea are used as input conditions for the simulation. Six cases are considered for the simulation based on the number of fishing lamp and the location of sliding rack.

The performance of helical hydro turbine in water pipe line depends on the sectional shape of turbine blade, pitch angle of turbine blade, solidity and number of turbine blades, To investigate the effects of these design factors on the performance of helical hydro turbine, flow analysis was carried out by using commercial code ANSYS CFX version 14..5. From CFD analysis we obtained the optimum design factors which were the asymmetric blade shape of NACA4420, the pitch angle of 15 degrees and the solidity of 0.3. These results can be used for the actual design of sphere-shaped helical turbine in water pipe line.

Dental brackets are widely used by the orthodontists to correct the misalignment of teeth in the mouth over a long period of time. In this study, finite element analysis of orthodontic bracket has been carried out for the observation of the stress distribution and deformation pattern in the different materials bracket (Stainless Steel, Ceramic, Titanium, Polycarbonate and Nitinol) when subjected to arch wire torsion and tipping force. The simulation results were further optimized with respect to bracket attachment surface. It was found that it is possible to know the change in result is correlated with the attachment surface of the stress and deformation due to change in diameter. The results confirmed that the finite element method has proved to be successful for proper design analysis for future development of the teeth bracket.

A three-dimensional computational fluid dynamics code is developed for predicting nonequilibrium flowfields over Mars entry probes. The numerical scheme is based on the cell-vertex finite volume method for a prismatic unstructured mesh system. Internal energy excitations and chemical reactions with finite rates are considered by introducing the two-temperature model of Park. Eight chemical species, C, N, O, CO, N2, NO, O2, and CO2, and nine chemical reactions are considered in the calculations. The developed code is verified in terms of prediction of heat flux to the body surface near the stagnation point of a Mars entry probe flying with the velocity of 6 km/s. The calculated heat flux reasonably agree with the calculated result in the past studies.

The regular safety inspection of vehicles in service has been tested up to now not by a plate type (dynamic) inspection system but by a roller type (static) inspection system in our country (in Korea). Therefore, the roller type inspection can not reflect the inertia force that there is a load transfer from the rear axle to the front axle during braking. In this study, before introducing the plate type inspection system, the effect on braking force characteristics according to entering velocities of vehicles in service are evaluated statistically. As the results, the reliable entering velocity range is about from 7 km/h to 14 km/h. Also, the regular vehicle safety inspection in domestic country need to adopt the plate type (dynamic) braking force inspection system which can reflect the inertia force.

The objective of this study is to predict the formability of sheet metal for the bladder press. The static implicit finite element method is applied effectively to analyze bladder forming processes using AutoForm software. The material used for forming analysis is AL2024, and the thickness of the plate is 1.6mm, 1.8mm and 2.0mm. Forming force is shown by 101.92kN～87.22kN. The result from the simulation analysis was applied to the bladder press system.

In this paper, the design of hydraulic system for leveling control of a large vehicle was developed. The hydraulic system for leveling control was consisted of four hydraulic actuators and two gravity referenced inclinometer. In order to verify the effectiveness of leveling system via simulation, Hydraulic actuators, vehicle and control algorithm were modeled using ADAMS which is a commercial dynamic analysis software for multi-body system. The test and simulation results of hydraulic actuator were compared and it showed the properness of simulation model. The effectiveness of hydraulic system and leveling control algorithm were verified via simulation results.

The hydraulic equipments has a high utilization in the many works such as the excavation, planation and crane works in the construction sites. They are an essential equipments in the construction site and the loading & unloading works of the large size objects. In the many parts which are composed of the hydraulic equipments, the main control valve(MCV) is the core of the equipments. The hydraulic energy from the pump controls the direction and the rate of flow by MCV. And the flow rate of the MCV inlet operate some actuators to perform the diverse action of the spool. So, it is important to analysis the shape of the flow path and the notch of the spool. In order to perform the optimal design of the 6-way valve, the study for the analysis of the flow path and the pressure distribution according to the pressure control, which to meet use condition, must be performed. In this study, we carried out the reverse-engineering of the MCV using the parametric technique as the first step in the research of the MCV. And we analyzed the shape of the flow path and the pressure distribution for the notch of the spool using the optimal modeling of the MCV.

The expansion of the display market could mass-produce the product which becomes the super-slim and ultra-lighting according to the demand of customer. This change etched the mobile display panel in order to make the thin glass. The wet etching refers to the process of removing selectively the unnecessary part in order to form the circuit pattern among the semi-conductor or the LCD manufacturing process. The wet etching can progress the etching about a large amount at a time but the thickness of glass is not smooth or not etched according to the process condition. In this study, the defect factor in the etching process tries to be analyze. The experimental design was established and the processing condition was optimized in order to minimize under non-etch part generation by the experiment of design.

In this study, development of the manufacturing system for the oriental medicine needle was carried through the wire drawing from the wire supply, straightness, heat treatment and surface treatment processes, and finally wire cutting or winding by the online process. As a result, a prototype manufacturing system for the oriental medicine needle wire has been developed. It has been shown that all development targets, such as, straightness, precision, surface roughness, tensile strength, discoloration, noise, diameter range and maximum production speed have been satisfied through the performance test.

In this paper, the design of hydraulic actuating circuit of doing over-running load was performed. Generally, the counter balance valve has been used to protect over-run or free falling of acuating system. But sometimes, it makes some undesirable problems such as pressure surge or vibration. To overcome such problems and satisfy the system requirements, we suggest the hydraulic circuit actuated by servo valve. In order to verify the properness of suggested hydraulic circuit, hydraulic actuator with servo valve was modeled using ADAMS/Hydraulic which is a commercial dynamic analysis software for multi-body system. Also, the effectiveness of hydraulic actuating circuit was verified via test bed and real plant.