鋼材 및 鋼板淸淨工程에 對한 考察

車一男 서울産業大學校 1981 논문집 Vol.15 No.1

In this paper, author investigated which process is better than Shot Blasting and pickling for cleaning of hot roll steel products. To induce the results, author first compared with the pickling process and the Shot blasting process theoritically. and than investigated the speciality and productivity of each process. The results are as follows: 1. The Blasting method is more economic and productive than the pickling method. 2. But, blasting method couldn't cover the all area of hot roll steel cleaning. For Example, Blasting method couldn't get the surface texture that is better than Ra 20μ. 3. For the efficient cleaning, It brings good result to use combining the pickling and the blasting method.

族削 加工面의 變形에 關한 切削모델에 對한 研究

車一男(IL Nam Cha),金潤濟(Yoon Jeh Kim) Korean Society for Precision Engineering 1988 한국정밀공학회지 Vol.5 No.1

Grid法에 依한 旋削 加工面의 変形에 關한 研究

車一男(IL Nam Cha),金潤濟(Yoon Jeh Kim) Korean Society for Precision Engineering 1986 한국정밀공학회지 Vol.3 No.4

덕트계 음장 모델링에 의한 능동 소음 제어에 관한 연구

차일남,이태연 서울産業大學校 1992 논문집 Vol.35 No.1

In many years, active noise control in a long duct have mainly been studied. Active noise control in long duct system deal with plane wave propagation at low frequency using adaptive filtering techniques. In most of these studies, the acoustic properties such as reflections and resonances inside the acoustic system have rarely been studied. In this paper, the modeling method of active noise control system using a fixed FIR filter for short-length rectangular duct was proposed. The acceptable attenuation on the real acoustic system and stability of the controller are predicted in this computational simulation.

正面形削加工에 있어 切削抵抗의 動的 擧動에 關한 硏究

車一男 서울産業大學校 1984 논문집 Vol.20 No.1

In metal cutting. the cutting force consist of static and dynamic components. In earlier works of metal cutting. however, a little attention has been paid to the dynamic component in steady cutting condition. To understand to behavior of the dynamic component in more detail in this study, the static and dynamic components of cutting force in face milling were measured by a dynamometer and the frequency components of cutting forces were also analyzed by stress frequency analyzer. Form measured results, the effects of cutting conditions and the dynamic components of cutting forces were investigated. when facing the workpieces made of steel. As a results, the following conclusions can be obtained. 1. The static and dynamic component of cutting force is propotional to the exponent of cutting volume. 2. The increasing of depth of cut is directly propotional to static component of cutting force. but the dynamic component of cutting force is stabilized by increasing of depth of cut 3. Dynamic component is the maximum at 100m/min. of cutting speed because SM15C material is developed build-up edge in that cutting speed.

加工表面域에 生成되는 殘留應力에 對한 硏究Ⅰ

車一男 서울産業大學校 1988 논문집 Vol.28 No.1

This study is to investigate the distribution of residual stress on the subsurface of the machining area. The operation was carry out within the range of normal working condition such as feed and cutting speeds. Turning operation was carry out orthogonal cutting condition on carbon alloy steel (SCM 4). The results are as follows. 1) It can be seen that in all cases the residual stress generate at the beneath of surface, it is increased to the maximum residual stress and then decreased. The maximum residual stress was located 4-25 un depth from the machining surface. 2) As the cutting speed increased maximum residual stress was increased to the certain speed (80-120 m/min) and then decreased. 3) As the feed rate increased, maximum residual stress also increased, the depth of maximum residual stress layer was deeper from the machining surfaces.

鋼板의 冷間벤당 加工에 있어서 쇼트블라스팅과 그 値數效果에 미치는 影響

車一男 서울産業大學校 1982 논문집 Vol.17 No.1

In the industries, we usually use a shot blasting process for the cleaning of steel plates. During the shot blasting, the steel plate surface would be work harden. These phenomena may be cause the crack as the bending of these plate. In this theses, author investigated the effect of shot blasting and specimen size on cold bending of plates by experiments. After Appling the shot blasting, the residual stresses occurred on the surface of the steel plate thereby the Surface hardness would be increased. Experiment results as follows; 1. The effects of work hardening is high carbon steel greater than low carbon steel. 2. The effects of cracking as cold bending is high carbon steel greater than low carbon.

자동차 실내 능동 소음제어를 위한 다채널 적응 알고리즘에 관한 연구

차일남,이태연 서울産業大學校 1993 논문집 Vol.37 No.1

Active control of acoustic noise is an application area of adaptive digital signal processing with increasingly interest along the last year. This work studied the implementation of the multichannel LMS filter and the application of this algorithm for the reduction of the noise inside a vechicle cabin using a number of 'secondary sources' drived by adaptive filtering of a reference noise source. Firstly, we propose the use of adaptive method for the time-varient optimal convergence factor. Secondly, we propose the use of adaptive delayed inverse model to estimate the elastic-acoustic transfer function presented in vechicle cabin. The original, primary source is often periodic, with a known fundamental frequency. A suitably filtered reference signal can thus be used to drive the secondary sources. An algorithm is presented for adapting the coefficients of an FIR filter feeding such a secondary source in such a way as to minimize the output of a suitably placed microphone. In this algorithm, the coefficients of adaptive filter driving an array of secondary sources can be adapted to minimize the sum of the squares of the outputs of a number of error microphones. The multichannel LMS algorithm displays that such an algorithm is considered suitable to used for the global suppression of noise in vechice cabin.

형상기억합금 작동기를 이용한 유연 구조물의 능동진동제어

차일남,박용군 서울産業大學校 1997 논문집 Vol.45 No.1

본 논문은 형상기억합금 액튜에이터를 이용한 유연 구조물의 능동 진동제어에 관 한 것이다. 먼저, 제시된 형상기억합금 자체의 동적 특성을 실험적으로 도출한 후, 이를 해밀톤 법칙과 연계하여 제안된 유연 구조물 시스템의 운동지배 방정식을 유도하였다. 외란에 강건한 슬라이딩 모드 제어기를 도입하여 제안된 시스템에 대한 능동 진동제어기를 설계하였다. 그리고, 제시된 제어 방법론의 타당성을 입증하기 위해 구조물 양측면에 형상기억합금이 .부착된 유연 구조물을 제작한 후, 능동 진동 제어 시스템을 실험적으로 구현하였다 그리고, 실험과 시뮬레이션을 통해 유연 구조물의 선단에 대한 강제진동과 위치 추적제어를 실시하였다. 연구 결과를 통해, 향후 형상기억합금 애튜에이터가 소형 유연 그리퍼에 매우 효과적으로 적용할 수 있음을 알 수 있었다. This paper deals with forced-vibration and tip-position tracking control of a flexible structure via shape memory alloy(SMA) actuators. Firstly, an experimental identification of dynamic characteristics for the employed NiTi SMA actuators itself with 5% extensional prestrain is conducted. A flexible structure of which two SMA wires are attached on the outer surfaces is then fabricated. In addition, a governing equation of lateral motion including the measured dynamic characteristics of the SMA actuator is formulated through Hamilton's principle and a state space control model is subsequently synthesized by means of mode summation. Moreover, a sliding mode controller inherently robust to external disturbances is adopted to carry out both forced-vibration control and tip-position tracking control in theoretical and experimental stages. In order to demonstrate the proposed methodology, a remarkable deflection suppression is evaluated in the forced vibration. Furthermore, tracking performances in sense of tracking accuracy and time are investigated in the position tracking control on the desired sinusoidal and step trajectories. Both the favorable results are to provide a feasibility of using the SMA actuator in a practical flexible gripper system.

3차원 밀폐 음장에서의 능동소음제어에 관한 연구

차일남,이태연 서울産業大學校 1993 논문집 Vol.38 No.1

A computer simulation is performed on the effectiveness of the active minimization of harmonically excited enclosed sound fields for producing global reduction in the amplitude of the pressure fluctuations. In this study for the appreciable reductions in total time averaged acoustic potential energy, ???, the transfer location strategies for three dimensional active noise control is presented based on the approximation in the total time averaged acoustic potential energy. In this study, the above theoretical basis is used to investigate the application of active control to sound fields of low modal density. By the use of room-like 3-dimensional rectangular enclosure it is demonstrated that the reductions in ???, can be achieved by using a single secondary source, provided that the source is placed within the half a wavelengths from the primary source and placed away from nodal line of the sound field. Concerning the reduction in ??? by minimizing the pressure in sound fields by the use of 3-dimensional rectangular enclosure, the effects of the number of sensors and the locations of these sensors are investigated. When a few models dominate the response it is found that if only a limited number of sensors are located away from nodal line and located at the pressure maxima of the sound field such as at each corner of a rectangular enclosure.