Earticle

In this study, factors analysis is performed for reducing friction in elevation motion of a large television stand over 50-inch. The first is a pipe type cross-section control for accurate position control of the piston rod. Here it was compared with the pipe type and labyrinth type orifice cross-section. The second study is for optimized piston structure development by comparison pipe orifice and labyrinth orifice. Consequently, in the orifice cross section study between pipe type and labyrinth type through CAE and experimental consideration, cross section of labyrinth type orifice is preferred for reducing of friction. The result of optimized piston structure development through experiment is fixed orifice specification as labyrinth orifice because pipe orifice is founded slip up/down phenomenon of the Ø0.4~1.0 orifice and the labyrinth orifice is not founded that of the Ø0.4~0.6 orifice both tests on 300 mm intervals.

The marine structures has a staggered array depending on the geographical characteristics of the surroundings. This wake flow occurs in the gap of such a staggered arrangement has a heavy influence on the vessels and structures. Also, Study on fluid flow around simple objects has contributed greatly to solve many engineering problems that occur in a variety of industries such as real fluid machinery, civil engineering, environment and etc. This study has progressed with changing aspect ratio and position of model by using PIV. It shows that speed reduction ratio is increased with the large movement of upper model and 1:2 aspect ratio.

The driving efficiency in vehicles depends on a weight lightening of wheels. Lightweight aluminum wheel research has been widespread over the years. Carbon wheels reduce weight by 50% compared to aluminum wheels and have high tensile strength and low heat absorption. This study was investigated to apply the carbon fiber of molding pressure to produce the carbon wheel. Carbon wheel of mold structure analysis was performed.

V-Coupling is commonly used as a mechanical fastener to connect the turbine housing and the bearing housing in a turbocharger assembly. The back plate between the turbine housing and bearing housing would be compressed by tightening torque of the coupling bolt in order to protect the gas leakage at a turbocharger’s operation. This paper presents the numerical and experimental method for the prediction of the mechanical behavior and sealing performance of the coupling system. The test was conducted to verify the finite element model by measuring the circumferential and axial direction strains of V-coupling under turbocharger’s assembly load. Finite element analysis was carried out to obtain the mechanical strains and contact pressures of the coupling. It can be seen that the analysis results are in good agreement with the measured strains from the coupling’s assembly load. And, the pressure distribution of the back plate also presented to identify the sealing performance of the turbocharger’s coupling system.

The composite material has the strong durability and light weight as inhomogeneous material. Nowadays, CFRP composite has been noticed as the light weight, high strength and long fatigue life. This study has been carried actively. In this study, the properties of tensile strengths of CFRP, stainless steel are analyzed, and compared each other. In order to secure the data, the tensile specimens with notches of same size by using CFRP, and stainless steel are manufactured and experimented. When the forced displacement of about 11.5 mm proceeds in case of stainless steel specimen, the maximum load of 31000 N is shown simultaneously with the fracture of specimen. When the forced displacement of about 6 mm proceeds in case of CFRP specimen, the maximum load of 16000 N is shown. So, the structural safety becomes highest at CFRP specimen among these specimens. In this study, the finite element analysis is carried out in order to compare with the experimental results. It is verified that the experimental and analysis results are similarly shown each other. Through the result of this study, it is thought that the simulation analysis data with no experiments are trustworthy at using as the real tensile experimental data.

In this study, electric propulsion leisure boat with 9 meters length is designed and the performances are investigated by CFD analysis and model test. Maximum speed of the developed boat is 15knots(7.7 m/s) using 80Kw electric motor. Catamanan type hull form with slender body is adopted considering high Froude number and large deck area. Two kinds of hull forms are designed and the performances are compared in resistance point of view. Wave patterns are observed to make clear the relationship between resistance performance and wave characteristics. The results show that not only wave interaction due to shoulder waves but also stern waves have a strong influence on resistance performance and CFD analysis including free surface can give useful informations at initial ship design stage for high Froude number catamaran boat.

Recently, as demand for Electric Car has been increasing, it has been a main factor that maximizing performance and ensuring the stability of the Electric Car battery to increase the reliability of Electric Car. Above all the study on thermal control in a big influence on the performance and battery life is growing in parallel. This study has compared cooling effect of an Electric Car battery between battery with Heat Sink and without Heat Sink for optimum design of Electric Car battery. Battery is simply modeled into four cells, divided into two cases of battery with Heat Sink that attached on the cell's side and without Heat Sink. And this research was conducted on forced convection. The battery which is designed by this way was numerically analyzed by CFX 14.5. Numerical results, revealed that the battery with Heat Sink was superior in terms of cooling effect. According to the numerical analysis by battery cell's temperature variations, the battery with Heat Sink turned out to be superior in cooling effect to the battery without Heat Sink.

For driver convenience, different types of transmission are being developed, such as AT(Automatic Transmission), AMT(Automated Manual Transmission), CVT(Continuously Variable Transmission) and DCT(Dual Clutch Transmission). To improve ride comfort and durability of the transmission, control system is important during launching and shifting process. For accurate control, vehicle mass and road gradient should be known. In this study, heavy duty vehicle’s mass and road gradient estimation method is developed. The method uses only signals from CAN(Controller Area Network) without applying extra sensors. Vehicle mass and gradient is estimated by LMS(Least Mean Square) method based on longitudinal vehicle dynamic model. To verify the estimation logic, test was conducted using a chassis dynamometer. The estimation results after test and test condition is compared. The error rate of vehicle mass estimation was 5 percent and gradient estimation result had 2 percent error.

In this study, we designed the 3-dimensional tire mold according to the A automobile company’s tire model, and analysed the distribution of temperature of mold using the numerical method when the heat flux and heat transfer time at the surface of tire mold were changed. A analysis region of mold was the 1/16 of entire mold, and the grid number was about more than 880 thousand. In order to analyze the temperature change of mold, the thinnest part of the mold was chosen as the research object, and then the temperature of 6 points on the vertical downward direction of the thinnest part was analyzed with the time change. While the numerical condition was that heat flux was 321,200 W/m2, 440,000 W/m2 and 880,000 W/m2, and measuring time was 0.1 second, 0.2 second, 0.5 second and 1 second, respectively. As a result, the temperature difference between the surface temperature and the lowest temperature of mold was 7.3℃ when the heat transfer time was 0.1 second. Also, the minimum temperature difference was almost 0.11℃ when the heat transfer increased to 1 second. It can be explained that the main material of tire mold was aluminum and its thermal conductivity was high (k=140 W/m·K). In addition, when the heat transfer time was more than 1 second, the heat flux of mold surface will be transmitted at the inside of the thinnest part, and the heat transfer will be a marked difference according to the shape of the thinnest part.

This paper studies the effect of a playtykurtic excitation signal on fatigue life. In general, a vibration test uses an excitation signal having a normal distribution of kurtosis 3. However, a vibration signal generated in a product’s operation environment has usually a non-normal distribution. This paper uses ZMNL method to generate a playtykurtic excitation signal having the equivalent power spectrum density with a reference vibration profile. This paper proposes a method which uses a fatigue damage spectrum ratio for studying the effect of a playtykurtic excitation signal on fatigue life. The fatigue spectrum damage ratio is obtained by dividing a fatigue damage spectrum acquired using the acceleration profile in which all conditions are the same except for the kurtosis by a fatigue damage spectrum acquired theoretically. This paper shows that the signal of kurtosis less than 3 can increase the fatigue damage spectrum by more than 2 to 4 times compared to the signal of kurtosis 3 using the fatigue damage spectrum ratio.

This paper presents development of the new haptic device for virtual wall collision test. Mathematical model of the proposed system considering virtual wall collision is developed and tuned by comparing force responses from simulation and experiment with free motion. To verify the effectiveness of the proposed model, a range of collision tests against virtual wall are accomplished, conditioned on different collision speeds to virtual wall. In addition, hybrid PI control scheme is applied to improve the performance of the proposed haptic system in virtual wall collision experiments.

Numerical analysis using k-ε model of unsteady state was performed to decide the optimal shape of power auxiliary apparatus in automotive engine. In order to obtain auxiliary electric power using coolant in automotive engine, shapes of 3 Types were compared. Furthermore to achieve the confidence of numerical analysis, the results of numerical analysis was compared with those of experiment. As the results, it showed that accuracy of numerical analysis was about 85~98%. Further the optimal shape, in this study, was Type-1, which had outer rounding R32.5, among 3 Types.

Magnesium alloy is becoming known for the lightest material in the metallic materials. Recently the automotive industry has a variety application to the light weight parts replacement. This study focuses on the mechanical property improving through a tiny amount’s CNT addition into the magnesium alloy as AM60. The CNT material is an arduous combination of the metallic materials. Therefore this study is concentrating on the contact force growth for the CNT material. Consequently, the made CNT is produced by the CVD process using the magnesium catalyst. The CNT material has dispersive with mechanical process into the molten AM60 alloy. The mechanical experiment result that hardness is 18% increasing and tensile strength is 13% increasing, better than the raw AM60 alloy on this investigation.

When the driver sits on the seat, the cushion supports more than 70% of body weight. Based on this the driver feels discomfort due to the pain and numbness caused by body pressure concentration in the ischial tuberosity. So, the purpose of this study is to analyze the stiffness of the seat cushion according to sitting strategy and to obtain basic data that can be reflected in the design of the seat cushion pad. First, the static stiffness characteristics of the seat cushion pad were determined through a static load test. Next, we measured the body pressure distribution of 20 subjects. Based on this, we derived 7 types of average body pressure distribution. And as the hardness distribution of the seat cushion, it was judged that it would be less hard feeling at the pressure concentration region. Finally, we compared the deflection and stiffness of the seat cushion using the average body pressure distribution and the static stiffness data of the seat cushion.

The analytical investigations of the filtering efficiency with multi-layered stainless screen filter, which is designed to generate swirling stream of micro metal dust from industrial manufacturing processes, were conducted. Compared to general filter dust collecting using bag filter, it can be expected that the metallic screen filters in this study enable the higher dust collecting efficiency of a system to be maintained even under harsh filtering conditions. The CFD analysis includes dust particles behavior, filtering efficiency, and pressure loss in the flow-field. The results show that the proposed 16 layered screen filter is able to collect 10 microns metal dust up to 97 % under 487.84 ㎩ differential pressure.

이 글은 『신인철학』을 중심으로 이돈화의 우주관과 인간관의 중심 내용을 서술하면서 그것이 지닌 동서철학 융합적 특징을 규명하고 생명철학적 의의를 밝힘을 목적으로 한다. 우주에 관한 논의에서 이돈화는 한울이 내재적인 동시에 초월적이라는 동학의 사유 전통을 계승했다. 즉 그는 한울이 그 자체로는 시공간을 초월한 존재이지만, 시공간 안에서 역동적인 운동을 한다고 생각했다. 이런 관념은 가까이로는 19세기 동학에 뿌리를 둔 것이지만, 멀리로는 동양의 사유전통을 계승한 것이다. 이렇게 이돈화는 동양의 생명론을 기반으로 하지만, 동시에 베르그손의 생명철학을 비롯해 일본의 실재론, 스피노자의 능산적 자연 개념, 진화론 등을 선택적으로 수용해 그 내용을 풍부하게 만들었다. 한편 인간에 관한 논의에서 이돈화는 우주적 존재로서 인간이 갖는 의미를 부각시켜, 인간격(人間格)이라는 새로운 개념을 제시했다. 인간격이란 우주적 존재로서의 인간의 이상적 인격이라 정의되는데, 그는 이 개념을 통해 인간이 우주의 중추적 존재로서 무궁히 진화하면서도, 다른 자연존재들과 유기적으로 연계되어 있음을 강조했다. 이 인간격 개념 역시 기본적으로는 동학의 인내천(人乃天) 사상 및 유학의 인간관에 뿌리를 두고 있지만, 동시에 그것은 서구 근대의 진화론과 베르그손의 생명철학에서 몇 가지 중요한 사상을 흡수해 그 내용을 더욱 충실히 한 것이라 할 수 있다. 이돈화의 우주관과 인간관에 보이는 동서철학 융합적 경향은 동서철학에 대한 비판적 계승 혹은 수용이라는 균형감 있는 태도를 견지하고 있다는 점에서 의의를 지닌다. 또한 19세기 동학과는 달리, 그의 철학은 생명에 관한 서양학문의 성과를 적극 흡수해 인내천 사상을 더욱 풍부하게 했다는 데 의의가 있다. 다만 19세기 동학이 지녔던 생명의 자연 내재성에 대한 강조 및 자연 경외의 정신이 다소 약화된 점은 아쉽다.

This study has as an objective to narrate the key contents of Lee Don-hwa’s (李敦化, 1884-unkown) views of the universe and human beings, to investigate the characteristics of integrated Eastern and Western philosophies, and to define their meanings in terms of philosophy of life, focusing on “New Human Philosophy (新人哲學).” In his discussion on the universe, Lee Don-hwa inherited the speculative tradition of Donghak (東學) in which “Hanul” was inherent and at the same time transcendental. Namely, he believed that Heaven itself was an existence surpassing time and space, but within that time and space, it moved dynamically. This view was based on the 19th-century Donghak at the nearest, but in a broader sense it inherited the speculative tradition of the Orient. Lee Don-hwa based his views on philosophy of life of the Orient, but at the same time selectively embraced Henri Bergson’s philosophy of life as well as Japans’ Realism, Spinoza’s concept of natura naturans, the evolution theory, etc. to make the content abundant. On the other hand, in his discussion on human beings, Lee Don-hwa proposed a new concept, “Ingangyeok (man's personality, 人間格)” by highlighting the meaning man can have as an universal existence. Ingangyeok is defined as an ideal personality of human beings as a universal existence, and through this concept, man evolves infinitely as the pivotal existence of the universe while stressing man is organically connected with other natural existences. The concept of Ingangyeok is basically based on Donghak’s doctrine of “Innaecheon (humans are Heaven, 人乃天)” and Confucian views on human beings, but Lee substantiated the content by absorbing several key ideologies from the evolution theory of the modern West and Bergson’s philosophy of life. The tendency of integrated Eastern and Western philosophies which Lee Don-hwa showed in his views on the universe and human beings is meaningful in that he adhered to balanced attitude in terms of critical inheritance or acceptance. Also, unlike the 19th-century Donghak, his philosophy actively absorbed achievements of Western learning on life and is significant in that he substantiated the ideology of Innaecheon. Only it is somewhat regrettable that it made an emphasis on the natural immanence of life and maintained weak respect for nature.

An injection unit is the important part which guide the melted resine into the mold. Once injection molding is performed, there will be a pressure of 33 MPa built up inside of injection cylinder body. It was confirmed that the crack occurs by internal stress on the 9 mm material when the machine is used for long time. Because the cylinder rod has material thickness of 9~12 mm during manufacturing process on the cylinder body, there would be 3 mm thickness differences. In this experiment, IDEAS, a computer aided structure analysis software, is used to present the optimized design condition. Insert rod with inner diameter of 9 mm was set as a normal and vary 3 mm in x, y axis direction. When the internal pressure of 33 MPa occurs at the injection unit, fix the x and y direction and find out the stress acting only in z axis. It was confirmed that the stress of 45~82 N/mm 2 was built up when the left of cylinder body had been set 9 mm by using a structure analysis. Also, it has been verified the thickness of the material on the left need to be greater and equal than 12 mm to prevent a material crack by an internal stress.

This study was performed for the optimizations of A-IMS assembly by analyzing the stress distributions under the different torque conditions. In order to achieve this, the numerical simulation was performed by SOLIDWORKS commercial code and the torque range that applied on the A-IMS assembly was increased from 10 N·m to 40 N·m. The simulation results were analyzed and compared in terms of Von-mises stress, principal stress, and displacement characteristics. The maximum stress distributions was observed on the contact surface of needle bearing which is located between tubular and solid shaft. It was found that the fracture of A-IMS assembly won’t occur until 30 N·m of torque. Therefore, it was concluded that there is no problem for the manufacturing of A-IMS assembly.

In this project, ECP(Electrical conducting polymer) gasket is used to detect the leakage of chemicals inside the reservoir. It is necessary that the electrical signal between ECP gasket and chemical leakage should be detected to protect the critical accident. This research introduce the leakage detection method to measure the electrical resistance of the cracked prototype pipe installed ECP gasket. Also the Arduino program is set to monitor the incident of chemical leakage.

This study evaluated the mechanical joining characteristics of substrate Al7075 using the filler metals of ER5356 and Al7075 to secure the joining integrity of the specimens by GTAW. The results of radiographic test show that the welded specimens meet the first level standard of KS D 2042. Besides, welding defects were not occurred. The tensile strengths of the specimens using the filler metals of Al7075 and ER5356 had 240MPa and 252MPa, respectively. The yield strengths were 132MPa and 120MPa, respectively. In case of using the filler metal of Al7075, However, in case of using the filler metal of ER5356, Two filler metals of Al7075 and ER5356 were similar to each other in tensile and yield strength.

There is a growing demand for improving the welding quality by reducing the machining error and improving the quality of the machined surface in the beveling for the improvement of the welding groove of the thick plate. For this purpose, it is necessary to develop an automatic beveling machine that adopts a cutting method that replaces the conventional oxygen flame cutting method. In this study, the cutting characteristics according to the machining conditions were evaluated during the face milling applied to the thick plate welding groove. We measured and evaluated cutting force for the machining conditions such as cutting depth, feed rate, chamfer angle, workpiece material, and material of the tool. We expect that this study is used as basic data for designing the stiffness of the spindle, the strength of the fixture and the power of the spindle and the feeding device when designing the automatic beveling machine.