Earticle

When operating at high speed on a vessel, a high-speed planing hull occurs nonlinear movements such as stern trim and large sprays. This phenomenon results in the hindrance of stability, embarkation and mission performance. Excessive stern trim during the slides decreases propulsion efficiency and visibility of helmsman due to porpoising and changing the attack angle of the fluid flowing into the propeller. To improve these problems, an outboard floating plate is installed on the cavitation plate to greatly suppress or eliminate the porpoising phenomenon. In this study, to analyze the performance of the floating plate mounted on the outboard engine, numerical analysis was carried out to investigate the resistance applied to the floating plate and the lift generated according to the change of the angle of attack and the flow velocity. The reliability of the floating plate mounted on the outboard engine was verified by applying the floating plate according to the speed and the angle of attack.

The multi-layered heat source model is a model that can cover most of existing studies and can be defined with a simple formula. Based on the methodology performed in previous studies, the welding heat source was found through experiments and FEM under the welding power conditions of three cases and the parameters of the welding heat source were analyzed according to the welding power. In this study, parameters of fiber laser welding heat source according to welding power were searched through optimization algorithm and finite element analysis, and the correlation was analyzed. It was confirmed that the concentration of the welding heat source in the 1st layer was high regardless of the welding power, and it was confirmed that the concentration of the welding heat source in the 5th layer (last layer) increased as the welding power increased. This reflects the shape of the weld bead that appears during actual fiber laser welding, and it was confirmed that this study represents the actual phenomenon.

Due to stricter environmental regulations of the International Maritime Organization (IMO), the number of ships fueled by Liquefied Natural Gas (LNG) is rapidly increasing. The International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code) limits the material of tanks that can store cryogenic substances such as LNG. Among the materials listed in the IGC Code, ASTM A553M-17 has been recently adopted as a material for LNG fuel tank projects because of its excellent mechanical properties at cryogenic temperatures. In shipyards, this material is being used to build tanks through Flux Cored Arc Welding (FCAW). However, there is a problem that magnetization occurs during welding and there is a big difference in welding quality depending on the welding position. In order to overcome this problem, this study intends to conduct basic research to apply laser welding to ASTM A553M-17 material. In Part I, the bead shape according to the welding output was analyzed and in PART II, ​​the penetration phenomenon according to the welding speed was analyzed after Bead on Plate (BOP) test. As a result of analyzing the bead shape according to laser power performed in this study, it was confirmed that the laser power and penetration depth are proportional to some extent. In addition, a range of suitable welding power was proposed for the 6.1mm thickness material performed in this study.

Parts made from CFRP materials are fabricated by hand or using automated layup and forming techniques. Finishing must be performed to meet the requirements for the necessary dimensions and geometry to facilitate assembly with other component parts. Parts such as airplane wings require trimming, milling and drilling to make CFRP into its final shape. In this study, the machining characteristics of CFRP were evaluated by manufacturing an end mill with a changed helix angle of the end mill. The cutting force was the lowest at the helix angle of 60 degrees, but the peeling state of the surface was the best at the point angle of 45 degrees.

In this paper, we break away from the method of removing and inspecting the GDI injector, measure the pressure change of the fuel rail pressure sensor when driving the GDI injector of a vehicle equipped with the GDI fuel system, and compare the results. analyzed.There was a pressure change in the fuel rail pressure sensor from the general drive GDI injector. There was no pressure change in the fuel rail pressure sensor when driving the GDI injector without injecting fuel. You can check the fuel injection status in the pressure change data of the fuel rail pressure sensor without removal the GDI injector.

Diesel engine is used many industrial fields such as ship, power plant and big-sized vehicles and so on. Roto cap is one of the parts of system of intake and exhaust valve. Roto cap consists of body, disc spring, spring & steel ball, retainer and stop ring. Disc spring is known as taking cyclic load and cyclic load leads to fatigue damage. This study aims to investigate the stability of disc spring due to fatigue damage. As the results, the fatigue life of disc spring according to cylic load could be predicted using fatigue analysis. Consequently, disc spring showed the stability of about 1.7~2 times for criterion load of 1370N.

This study was conducted for the purpose of suggesting a standard that can be used under ambient temperature by improving the low mechanical and thermal properties of ABS. PC was used as a filler, and post-curing conditions of the ABS/PC blend injection material were investigated. It was found that the ABS/PC blend injection material having a PC content of 20 wt.% or more showed little change in tensile properties at a temperature of 50°C, and a decrease in tensile properties of less than 10% at 80°C.

Thermal and wind panels are installed on offshore oil and gas platforms to protect personnel, equipment and structures. However, in general, panels are designed and manufactured through trial and error based on performance tests. For this reason, it is difficult to develop and design a heat sink in the Korean shipbuilding and offshore equipment industry due to the lack of performance test data and limited experience. In this study, the experimental results performed to verify the performance of the thermal and wind panels were analyzed, and the characteristics and performance characteristics of the thermal and wind panels were investigated. The conclusions drawn from this study will be useful in terms of the design and development of shielding.

The event recording devices such as EDR and DTG have recently been developed and installed in automobiles. The reliability of EDR application is being conducted in many previous studies, but with the development and development of autonomous vehicles, it is necessary to study the reliability of EDR and DTG application results for programs that can analyze autonomous driving. Therefore, in this study, the analysis was carried out in a way to secure the reliability of the application results of EDR and DTG of Carmaker, which can analyze the traffic accident analysis program PC-Crash and autonomous driving, and secure the reliability of the Carmaker program that applied EDR in Korea and abroad. As a result of the analysis, it was found that the speed error rate gradually increased from high speed to low speed, and the maximum error speed was less than 5 km/h through the average error rate for each speed. In the future, it is thought that it can be usefully used for analysis of traffic accidents in the event of autonomous vehicle accidents.

Application of a very high internal pressure on the thick-walled pressure vessel induces beneficial compressive tangential residual stresses near the bore of the pressure vessel after unloading the internal pressure. However, a reverse yielding due to the Bauschinger effect during the unloading process causes the reduction of the compressive residual stress near the bore. In order to evaluate the autofrettage residual stress distributions of the thick-walled pressure vessel, the Bauschinger effects were considered. Magnitudes of the compressive residual stresses at the bore determined by considering the Bauschinger effects decreased by about 25 percent, compared to the case of linear elastic unloading, i.e., without Bauschinger effects. Measured residual stress distributions agreed fairly well with the calculated distributions considering the Bauschinger effects.

An important variable in the oil-water separation process is the size and dispersion diagram of the bubbles formed in the induced gas flotation(IGF). In this study, the influence of the behavior and characteristics of the fine bubbles generated in the IGF device on the oil-water separation performance was evaluated by a numerical analysis method. For this reason, it constitutes Grid system suitable for bubble characteristic analysis. By applying Reynolds-averaged Navier-Stokes equations, a continuous abnormal flow analysis model of water and air was established. For the numerical flow analysis model, we applied the Eulerian-Eulerian approach that can be used for the reaction model in which bubbles are formed at one point of the Euler method applied when the base is liquid. As a result, it was confirmed that the bubbles in the IGF device were evenly dispersed as the flow velocity of bubbles increased and the particle size decreased. Such a phenomenon was caused by changes in Reynolds number and drag related to the flow characteristics, and could be explained by Stokes' law of viscosity.

In recent, fiber-reinforced composites have been widely used in many fields because of their excellent performance. In order to manufacture lightweight, high-performance, and inexpensive composites various laminated structures were designed. Six types of hybrid composites were fabricated with glass/basalt/aramid fibers by VARTM process. The effect of the laminated structure on the mechanical properties of composites was investigated through impact energy, tensile and bending strength. Compared to other conditions more higher impact energy was obtained when the aramid fibers were in the center position and more higher bending strength was obtained when the fibers are laminated in the order of increasing bending performance from top to bottom. The laminate structure did not affect tensile strength which mainly depends on the property of fibers.

In this study, the structural analysis of sway brace device for earthquake-proof which can fix a pipe installed in the building was carried out. The sway brace device was analyzed to evaluate not only the deformations of adaptor fitting, support brace member, structure attachment fitting and clamp sway brace fitting that compose it, but also the effective stress of adaptor fitting combined with support brace member by shear bolt. As a result of structural analysis, it can be seen that the deformation of support brace member influences most of the deformation of sway brace device and the design of adaptor fitting must be modified. Above all, it indicates that the sway brace device is suitable for Korea Fire Institute(KFI) approval standard since its total deformation is smaller than the maximum displacement proposed by KFI. The result of this study can be effectively used to investigate the effective stresses and deformations without the performance test of sway brace device according to its setting angle.

In order to identify the CAN message sent from the ECU, the CAN waveform and operating current were measured during the operation of the CAN driver.CAN ID was identified in the same phase as the measured voltage waveform and operating current, and reverse engineering was performed .And, by measuring CAN bus wire EMI noise, it was tested whether CAN ID was identified.CAN ID verified ECU data using CAN analyzer.

Due to stricter environmental regulations of the International Maritime Organization (IMO), the number of ships fueled by Liquefied Natural Gas (LNG) is rapidly increasing. The International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code) limits the material of tanks that can store cryogenic substances such as LNG. Among the materials listed in the IGC Code, ASTM A553M-17 has been recently adopted as a material for LNG fuel tank projects because of its excellent mechanical properties at cryogenic temperatures. In shipyards, this material is being used to build tanks through Flux Cored Arc Welding (FCAW). However, there is a problem that magnetization occurs during welding and there is a big difference in welding quality depending on the welding position. In order to overcome this problem, this study intends to conduct basic research to apply laser welding to ASTM A553M-17 material. As a result of analyzing the bead shape according to laser BOP speed and Energy density performed in this study, it was confirmed that the penetration and energy density are proportional but the penetration and BOP speed are inverse proportional to some extent. In addition, a range of suitable welding speed and energy density were proposed for the 6.1mm thickness material performed in this study.

In this study, for the treatment efficiency of the IGF process for the treatment of produced water (PW) discharged from the oil sands plant, the bench-scale oil sands plant PWT package was designed, manufactured and evaluated to verify the efficiency of the process. The microbubble generation efficiency and microbubble size change according to the circulation pump pressure were observed, and the correlation between influent concentration and temperature, residence time and oil-water separation performance was analyzed.

Numerical analysis for flow and noise characteristics of sirocco fan design factors is conducted in this study. 4 cases of blade angle(α=24°~30°) and 5 cases of RPM(390~1170RPM) are calculated. Flow characteristics are compared for the number of blades. Outlet flow rate is tended to decrease as the number of blades increased. There is little difference in the flow characteristics for the angle of blade. The highest outlet flow rate is predicted at α=24°, and the lowest at α=28°. Flow and noise characteristics are compared for α=24° and 26°. Outlet flow rate is almost similar in both cases, but noise for α=24° is predicted higher at high RPM conditions.

An implementation of OSEK NM, a network management protocol for automotive embedded systems, has been defined. In this experiment, the NM ID of each ECU of the vehicle is reverse-engineered when the vehicle is parked with a discharged battery, and the power management status and error status of each ECU and node are identified through NM ID OPCODE analysis, Sleep status, and Wake-up status, LIMP HOME status, were analyzed. After analyzing the NM OPCODE to find the faulty ECU, remove the cause of the failure and analyze the sleep mode entry state.In order to prevent the vehicle battery from being discharged, additional research is needed on how to enter the forced sleep mode when a failure not related to vehicle security occurs.

The prospect of the new railway construction has led to resistance from residents, partly based on noise and vibration issues. Particularly, as tracks often pass closely to residential dwellings, constructors are then required to take account of noise and vibration. So the prediction of noise and vibration for train is very important thing. The train noise and vibration nearby the elevated railway make one specific issue. For the elevated railway, this paper concerns the rolling noise by the wheel/rail and the structure-borne noise by the bridge. Based on the results, this paper proposes the source model of elevated structure-borne noise and the calculation model for elevated railway noise. Also prediction model is presented with rolling noise and elevated structure noise which are calculated by considering the power level of a source for one-third octave band, ground absorption and barrier deflection. A lot of empirical data is needed to predict the noise and vibration. And one of the best ways to control the wayside noise is to analyze the noise level.

A heat pump system using wasted heat from thermal effluent to supply the heating energy can reduce energy consumption and emissions of greenhouse gases by greenhouse facilities nearby. The Jeju National University consortium constructed a heat pump system using the thermal effluent from the Jeju thermal power plant of KOMIPO to provide with cool or hot water to greenhouse facilities located 2.5km from the power station. In this paper, the system configuration of the heat pump system was summarized, and the results of operations for demonstration of a heating performance carried out during the winter season in 2018 were investigated. Therefore, if the heating control by supplying thermal effluent to the facility greenhouse, it can contribute to reducing the energy cost and improving quality.

In this study, the effects of fuel injection pressure changed from 45 to 65 MPa on combustion and emission characteristics were investigated in a common rail direct injection (CRDI) diesel engine fueled with diesel and palm oil biodiesel blends. The engine speed and engine load were controlled at constant 1700rpm and 100Nm, respectively. The tested fuel were PBD20 (20 vol.% palm oil biodiesel blended with 80 vol.% diesel fuel). The main and pilot injection timing was fixed at 3.5°CA BTDC and 27°CA BTDC (before top dead center), respectively. The experimental results show that the combustion pressure and heat release rate increased. In addition, the indicated mean effective pressure (IMEP) and maximum combustion pressure increased with an increase of the fuel injection pressure. Hydrocarbon (HC), smoke opacity and carbon monoxide (CO) decreased, but oxides of nitrogen (NOx) emissions increased as fuel injection pressure increased.

The prospect of the highway traffic road construction has led to resistance from residents, partly based on noise and vibration issues. Particularly, as tracks often pass closely to residential dwellings, constructors are then required to take account of noise and vibration. So the prediction of noise and vibration for highway traffic is very important thing. The highway traffic noise and vibration make one specific issue. For the highway traffic road, this paper concerns the noise by the wheel/tire and the structure-borne noise by the road. Based on the results, this paper proposes the source model of highway traffic noise and the calculation model for highway traffic noise. Also prediction model is presented with traffic noise which are calculated by considering the power level of a source for one-third octave band, ground absorption and barrier deflection. A lot of empirical data is needed to predict the noise and vibration. And one of the best ways to control the wayside noise is to analyze the noise level.

Stone cutting process that it became with the tree, after fixing with the neck which is was fixed the stone in portable type transfer and department with cutting department which is in the process of operating and it transferred it was in the process of moving with the method which cuts with hour vibration where the stone will reach to the saw blade it was caused by, the raw materials waste and the inferior good which under the actual conditions which are disconnected from the default location of the stone are caused by soaking pit of the stone were under occurring. Consequently objective of this research currently the fixation stone cutter which is used from the stone processing and cutting enterprise about lower the productivity falls on a large scale with fixation, the raw materials loss to be many is sufficient the satisfactory degree of the enterprise considerably and to be insufficient in order the problem which is like this to solve the new cutting technical develop.

Due to industrial development, the importance of GD&T tolerance is growing day by day. Roundness measurement means the size deviated from the ideal circle. Roundness evaluation methods include LSCI, MZCI, MCCI, and MICI. In this experiment, measurement deviations according to roundness measurement methods such as radius method, diameter method, and three-point method were studied using the same roundness specimen. The measurement method was measured 20 times each by the measurer, and the average value and dispersion of each data obtained through the experiment were confirmed. Through the experiment, it was confirmed that the diameter method, the three-point method, and the radius method were measured and spread out in the order of magnitude. In addition, the interrelationship according to each measurement method was confirmed using the experimental design method. The test statistic value (P) was greater than 0.05 through hypothesis testing, and the null hypothesis was rejected and the alternative hypothesis was adopted in the experiment.

In this study, we proposed a method to measure and analyze the vibration problem in cargo pipes during the sea trial for 80K LPG vessel. Pipe vibration was identified as resonance with the propeller 1st order component, which is one of the main excitation forces in the normal continuous rating (NCR). In order to avoid resonance in the NCR, a reinforcement method was established through finite element method (FEM) analysis. In the future, the advance application of cargo pipe reinforcement is expected to be useful for reducing the vibration of the cargo pipes in ships whose order and specification are similar to those of the vessel used in this study.

I propose an algorithm to detect defects in the production of wire mesh using computer image processing. The process is explained as follows, First reading consecutive frames coming through the camera, then the preprocessing process is performed. Second calculate the absolute difference between the two images to distinguish the moving wire mesh from the unnecessary background image. Third based on the past moving data of the welded wire mesh, predict and track future movement. As a result of observing the samples of some defective welded wire mesh products, it was confirmed that the horizontal line of the defective wire mesh had a higher height value of the tracked wire netting. Therefore it is possible to judge whether there is a defect or not at the same time without any additional process to judge. Finally, shear strength test were performed on the welds determined to be normal products by the algorithm proposed in this paper, so that I could verify the reliability and validity of the proposed algorithm.

In this research, we have developed the non-contact automatic washer system for two-wheel motor vehicle through structural and fluid analysis. The structural analysis of mainframe was performed for the safety of the bike washer system, and multi-phase fluid analysis was applied for the washer cleaning performance which was analyzed the surface shear stress while varying the nozzle angle. As a result, we have developed the washer system by deriving the spray angle for the shear stress area and by analyzing the housing shape that takes into consideration structural stability. The performance of this washer system was verified by measuring the gloss before and after cleaning in the evaluation of the cleaning performance test of the system.

Butterfly valves have been used to control the flow rate of various fluids in many industries because it have unique manageability compare to other valves. However, when a defect occurs due to the failure of the backlash of the power transmission part and the pin breakage of the butterfly valve due to the absence of the design capability of the valve, it is difficult to analyze the cause and maintain it. In this paper, a study was conducted to secure the reliability of the valve by performing structural analysis and analysis using a 3D model of the product to manufacture a high-quality valve.

In this study, durability and reliability were verified by developing a compost crushing equipment for mushroom cultivation that can perform both the compost turning process and the rice straw grinding process. Structural analysis and vibration analysis were performed. The designed compost crusher is designed with sufficient strength within the range that satisfies the safety factor as a result of structural analysis. In the case of the basic frame, it is judged to have sufficient safety against various impacts that may occur during transport or operation. As a result of the performance evaluation of the compost grinding device, it was measured to be capable of crushing and turning 11,630kg of compost in one hour, and it showed excellent performance in terms of work volume and loadable height.