• 오토저널
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• 제13권6호
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• pp.90-100
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• 1991

This paper represents the analysis of the sheet drawing by applying the Matrix method to Hill's slip-line field for small reduction and indirect type slip-line field in case of large reduction. Results of the analysis represent the relation between the reduction ratio and the die wall pressure, mean drawing stress through rough die. The limitation on the use of this slip-line field is described. When the reduction ratio is given, the optimum die angle is analyzed in this paper.

• 반도체디스플레이기술학회지
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• 제19권4호
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• pp.18-21
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• 2020

Undetected wafer slip during the lift pin-down motion in semiconductor equipment may affect the center to edge variation, wafer warpage, and pattern misalignment in plasma equipment. Direct measuring of the amount of wafer slip inside the plasma process chamber is not feasible because of the hardware space limitation inside the plasma chamber. In this paper, we demonstrated a practice for the wafer lift pin-up and down motions with respect to the gear ratio, operating voltage, and pulse width modulation to maintain accurate wafer position using remote control linear servo motor with an experimentally designed chamber mockup. We noticed that the pin moving velocity and gear ratio are the most influencing parameters to be control, and the step-wised position control algorithm showed the most suitable for the reduction of wafer slip.

• 재활복지공학회논문지
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• 제8권3호
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• pp.169-175
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• 2014

본 연구에서는 전동휠체어 주행 시, 슬립 현상으로 인해 발생할 수 있는 경로 이탈 및 제어 불능에 대처할 수 있는 슬립 제어기에 관한 연구로 주요기능인 슬립 검출기를 제안하고자 한다. 전동휠체어에서 슬립의 검출은 주행과정에서 전동휠체어와, 모터의 상태를 검출하는 것으로, 이를 위해 6축 IMU 센서와 좌우 모터에 연결되어 있는 엔코더를 통해 산출된 정보를 슬립 검출 알고리즘을 이용하여 슬립율을 산출한다. 이렇게 산출된 슬립 비율은 전동휠체어의 안전성 향상을 위한 제어변수로 사용된다. 본 연구에서 제안한 슬림 검출기 실험 결과 제안된 경로에서의 슬립 현상을 확인 할 수 있었다. 실험 중 최대 슬립 율 검출 구간은 전동휠체어의 선회시 발생하는 것으로 확인 하였다.

• Steel and Composite Structures
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• 제38권3호
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• pp.241-255
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• 2021

In order to study the interfacial bond-slip behavior of steel reinforced recycled concrete (SRRC) under cyclic loading, thirteen specimens were designed and tested under cyclic loading and one under monotonic loading. The test results indicated that the average bond strength of SRRC decreased with the increasing replacement ratio of recycled concrete, whereas the bond strength increased with an increase in the concrete cover thickness, the volumetric stirrup ratio, and the strength of recycled concrete. The ultimate bond strength of the cyclically-loaded specimen was significantly (41%) lower than that of the companion monotonically-loaded specimen. The cyclic phenomena also showed that SRRC specimens went through the nonslip phase, initial slip phase, failure phase, bond strength degradation phase and residual phase, with all specimens exhibiting basically the same shape of the bond-slip curve. Additionally, the paper presents the equations that were developed to calculate the characteristic bond strength of SRRC, which were verified based on experimental results.

• 대한조선학회논문집
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• 제51권1호
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• pp.1-7
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• 2014

The present study numerically investigated the effect of the advance ratio on the wake characteristics of the marine propeller in the propeller open water test. Therefore, a wide range of the advance ratio(0.2${\kappa}-{\omega}$SST Model are considered. The three-dimensional vortical structures of tip vortices are visualized by the swirl strength, resulting in fast decay of the tip vortices with increasing the advance ratio. Furthermore, to better understanding of the wake evolution, the contraction ratio of the slip stream for different advance ratios is extracted from the velocity fields. Consequently, the slip stream contraction ratio decreases with increasing the advance ratio and successively the difference of the slip stream contraction ratio between J=0.2 and J=0.8 is about 0.1R.

• 대한기계학회논문집
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• 제13권5호
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• pp.847-854
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• 1989

본 연구에서는 V-벨트 CVT의 핵심인 변속비-부하토오크-축력에 대한 이론적 연구에 이어 실험적 연구를 통하여 전 연구에서 구한 이론식과 비교 검토하고 V-벨트 CVT의 기초 설계자료를 얻고자한다.

• 대한기계학회논문집
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• 제18권10호
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• pp.2585-2596
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• 1994

Many particle filled materials like Poweder/Binder mixtures for poweder injection moldings, have complicated rheological behaviors such as an yield stress and slip phenomena. In the present study, numerical simulation programs via a finite element method and a finite difference method were developed for the quasi-three-dimensional flows and the two-dimensional flow models, respectively, with the slip phenomena taken into account in terms of a slip velocity. In order to qualitatively understand the slip effects, typical numerical results such as vector plots, pressure contours in the cross-channel plane, and isovelocity controus for the down-channel direction were discussed with respect to various slip coefficients. Slip velocities along the boudary surfaces were also investigated to find the effects of the slip coefficient and processing conditions on the overall flow behavior. Based on extensive numerical calculations varying the slip coefficients, pressure gradient, aspect ratio, and power law index, the screw characteristics of the extrusion process were studied in particular with comparisons between the slip model and non-slip model.

• 유공압시스템학회논문집
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• 제4권1호
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• pp.13-17
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• 2007

The brake gain adaptive wheel slip controller for a vehicle is designed in this paper. The brake gain from braking pressure to braking torque defined by friction coefficient, friction area and effective friction radius is estimated by the adaptive law based on the wheel slip dynamics. And the wheel slip controller is designed based on the estimated brake gain. The robustness of the designed controller is analyzed using Lyapunov function and the convergence of brake gain is verified. Proposed wheel slip controller is verified via CarSim simulation with two kinds of desired wheel slip ratio.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.226-233
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• 1998

In this paper, an experimental study was performed to investigate the speed ratio-torque-thrust characteristics for metal belt CVT. It is observed from the experimental results that nondimensional secondary thrust force follows with the existing theoretical formula with ${\mu}$=0.09~0.12 depending on the torque and the speed ratio. In order to represent these characteristics, an effective friction coefficient was introduced. Also, the slip characteristics between the belt and the pulley were investigated experimentally and traction coefficients at gross slip were obtained for various speed ratios. Using the traction coefficients and the effective friction coefficients, an improved formula for the secondary thrust force was suggested assuming that thrust force is the summation of the thrust of pseudo inactive arc and the thrust of pseudo active arc. The effective friction coefficient and the improved formula for the speed ratio-torque-thrust relationship suggested in this work can be used to obtain the appropriate secondary thrust.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3096-3101
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• 2008

Selective Catalytic Reduction (SCR) technology is well-known to be effective for the reduction of NOx emission. So car manufacturers has adopted Ures-SCR system to be satisfied with emission regulation. This paper discusses the effective of $NH_3/NOx$ ratio and SCR catalyst temperature in the $NH_3$-SCR reactor on DeNOx performance. So it is shown the characteristic of NOx conversion and ammonia slip using the $NH_3$ instead of Urea-Solution. From the result of this study, it is found to optimize $NH_3/NOx$ ratio to have the best case of high NOx conversion and low ammonia slip at variable SCR catalyst temperatures. Lastly, it is also found the characteristics of NOx conversion and ammonia slip with compared with Urea.