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401.
Wu-Joan Kim Jaehoon Yoo Zhengshou Chen Shin Hyung Rhee Hye-Ryoun Chi Haeseong Ahn 《Journal of Marine Science and Technology》2010,15(3):230-241
The results of the design analysis for a sailing yacht’s hull and sails are reported. The results were used to confirm the
design of a 30 ft long sloop, which was planned, designed, and built in Korea for the first time in history. Flows around
a sailing yacht above and under the free surface were analyzed separately using both computational and experimental methods.
For the underwater flow analysis, turbulent flow simulations with and without free surface wave effects were carried out for
the canoe hull with keel/rudder. The computed drag and side forces on the hull model were compared with the measurement data
obtained from the towing tank experiments. In order to assess the sail performance, another set of computations was carried
out for the flow around a sail system composed of main and jib sails with a mast. The present study demonstrates that, for
the design analysis of a sailing yacht, computational fluid dynamics techniques can be utilized with a reasonable level of
confidence. 相似文献
402.
S.-J. Lee M.-S. Jang Y.-G. Kim G.-T. Park 《International Journal of Automotive Technology》2011,12(3):425-432
Occupant classification in a passenger seat is one of the critical components for any advanced airbag system. Many automotive
electronic suppliers and engineers predict that the camera will be the next generation sensor for active and passive safety
systems because it has several advantages compared to other sensors. The present paper describes a stereovision-based occupant
classification system (OCS) and intelligent algorithm with embedded system by which triggering of the airbag deployment can
be controlled. The system consists of a pair of stereo cameras and dual Digital Signal Processor (DSP): the first DSP is for
the stereo matching processing, and the second is for occupant classification. The results show that the reaches 97%, and
the processing time is 960 ms. Such performance indicates that the feasibility of the system as an embedded OCS is high. 相似文献
403.
Byung Chul Choi Seunghyeon Cho Chang-Wan Kim 《International Journal of Automotive Technology》2018,19(3):455-461
In a MacPherson strut suspension, the side load is inevitably generated and it causes friction at the damper reducing riding comfort. In this paper, to solve this problem, progressive meta-model based sequential approximate optimization (SAO) is performed to minimize the side load. To calculate the side load, a wheel travel analysis is performed by using flexible multi-body dynamics (FMBD) model of suspension, which can consider both finite element method (FEM) and multi-body dynamics (MBD). In the optimal design process, meta-model is generated by using extracted sampling points and radial basis function (RBF) method. As a result of optimal design, spring setting positions that minimize the side load are obtained and by using optimal spring setting positions, the suspension FMBD model was constructed. 相似文献
404.
S. K. Kim S. S. Kim Y. G. Cho H. K. Jung 《International Journal of Automotive Technology》2016,17(2):255-263
Tolerance design of vehicle suspension is an important factor that affects the ride and handling quality and cost of the vehicle. Also, applying geometric tolerance to an analysis model is found to be a difficult process. This paper presents a method for tolerance analysis of wheel alignment of vehicle suspension. Monte-Carlo simulation method is applied to multibody elasto-kinematic model to analyze the accumulated geometric tolerances. As an example, Macpherson Strut Type front half car model is used, and wheel alignment dispersion and contribution ratio to the dispersion by accumulated geometric tolerances is computed. This paper also presents an efficient modeling and analysis method for elasto-kinematic model of vehicle suspensions by computing the stiffness matrix analytically. The simulation results of a Macpherson Strut Type demonstrates the validity and accuracy of the proposed method. 相似文献
405.
Kwang Hyo Jung Ho Hwan Chun Hee Jung Kim 《Journal of Marine Science and Technology》2008,13(4):317-327
The aerodynamic characteristics of NACA6409 in the vicinity of the ground were experimentally studied in a wind tunnel. Lift
and drag forces, the pitching moment, and the center of pressure were measured with respect to various major aerodynamic parameters,
such as the ground clearance, the angle of attack, the aspect ratio (AR), and the endplate type, which resulted in a total
number of 420 conditions. In addition, a smoke trace test was conducted to visualize the flow pattern around NACA6409 in the
vicinity of the ground. As a result of the ground effect and the influence of the endplate, the lift-to-drag ratio increased
at low ground clearance and the center of pressure moved forward to the leading edge; that is, the endplate and ground effects
were equivalent to the aerodynamic advantage that results from increasing the AR of the wing. Extended experimental results
are useful for understanding the aerodynamic characteristics influenced by each aerodynamic parameter during ground effect
as well as for verifying numerical simulation. 相似文献
406.
Jaecheol Cho Yongseok Lee Woojung Kim Siyoul Jang 《International Journal of Automotive Technology》2018,19(3):463-472
A frictional torque was generated by a lubricated slip contact between a wet clutch pad and a steel separator during a wet clutch engagement. It is necessary to understand the generation of frictional torque to improve the performance of the frictional torque transfer and the durability of the wet clutch system. The analytical modeling of wet clutch torque transfer considers the effects of surface roughness, permeability, the elastic modulus of the frictional material, lubricant viscosity, temperature, etc. Experimental apparatus for wet clutch engagement was designed for the measurement of frictional torque transfer during wet clutch engagement. The experimental results were compared with the analytical results under various operational conditions for the verification of the theoretical analysis to evaluate the performance of the wet clutch system. Some correlations were investigated between the experimental and analytical results. We found that computation by analytical modeling can predict the effects of oil temperature, applied force, and slip speed, as well as engagement period and frictional torque transfer shapes. 相似文献
407.
Hyunsoo Kim Jaehwan Yang Kang-Dae Lee 《Transportation Research Part D: Transport and Environment》2009,14(5):291-299
This paper presents a vehicle routing approach for the transport of end-of-life consumer electronic goods for recycling in South Korea. The objective is to minimize the distance of transportation of end-of-life goods collected by local authorities and major manufacturers’ distribution centers to four regional recycling centers located. A vehicle routing problem is constructed for each regional center, and a Tabu search is applied to solve it. Computational results using field data show that the method outperforms existing approaches to reverse logistics. 相似文献
408.
This paper presents a new controller design method based on a data-mining polynomial algorithm. We show application of a polynomial
data-mining algorithm, where an input-state linearized polynomial vehicle model is developed for very low speed operation
and, without introducing any processes with fudge factors, control inputs of a nonlinear system are obtained in the original
coordinates. We verify the developed modeling method and controller design method through numerical experiments. 相似文献
409.
In this study, NOx conversion characteristics of a urea selective catalytic reduction (SCR) system equipped on a heavy-duty diesel engine were evaluated through engine dynamometer bench tests over a scheduled world harmonized transient cycle (WHTC). Also, based on transient SCR simulations, the thermal management strategy to improve SCR NOx conversion efficiency was investigated. As a result, it was found that a selective increase in exhaust temperature at low temperature period would be a useful measure to increase SCR efficiency on WHTC mode. From the baseline SCR efficiency of around 98 % on WHTC mode, the current simulation results have shown that around 99 % level of SCR efficiency would be achievable by increasing exhaust temperatures with modifying diesel exhaust fluid (DEF) dosage. Another valuable contribution of this study is that the design guidelines for controlling exhaust temperature and DEF injection to obtain a target NOx conversion efficiency are presented for SCR systems of heavy-duty diesel engines on transient operating conditions. 相似文献
410.
This paper presents a space vector current controller for a brushless permanent magnet motor in electric and hybrid electric
vehicles. The proposed current controller selects space vectors based on the sector selection under a three-level hysteresis
comparator to decrease the current ripple. The proposed approach can improve the performance of a brushless PM drive such
as the average switching frequency and the total harmonic distortion (THD) compared with the conventional hysteresis current
control. The experiment is performed first to verify the proposed control. Then, the method is implemented in a hybrid electric
vehicle simulation model with standard driving cycles based on the control strategy to evaluate the drive performance in the
vehicle system. The experimental and simulation results indicate that the presented control can improve the performance of
the brushless PM machine drive. 相似文献