• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.1
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• pp.9-17
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• 2013

A considerable deal of work has been carried out to get an insight into the gas-solid suspension flows and to specify the particle motion and its influence on the gas flow field. In this paper an attempt is made to develop an analytical model to study the effect of nozzle inlet/exit pressure ratio, particle/gas loading and the particle diameter effect on gas-solid suspension flow. The effect of the particle/gas loading on the mass flow, Mach number, thrust coefficient and static pressure variation through the nozzle is analyzed. The results obtained show that the presence of particles seems to reduce the strength of the shock wave. It is also found that smaller the particle diameter is, bigger will be the velocity as bigger particle will have larger slip velocity. The suspension flow of smaller diameter particles has almost same trend as that of single phase flow with ideal gas as working fluid. Depending on the ambient pressure, the thrust coefficient is found to be higher for larger particle/gas loading or back pressure ratio.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4751-4755
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• 2011

This study investigates the plastic suspension assembly which is installed on inside of vehicle seat and support passenger's back to supply the comfortable ride performance. It aims to develop the structural design in order to support driver's back uniformly and assemble seat back frame with plastic suspension effectively. The part of suspension is designed by considering the body pressure distribution of driver and it has the same size as the practical model on simulation analysis. It is confirmed that the analysis result of plastic suspension approaches the practical measured values and the better body pressure distribution can be obtained as compared with the existing wire type.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1125-1130
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• 2007

This paper presents a maneuver analysis of a full-vehicle featuring electrorheological (ER) suspension and ER brake. In order to achieve this goal, an ER damper and an ER valve pressure modulator are devised to construct ER suspension and ER brake systems, respectively. After formulating the governing equations of the ER damper and ER valve pressure modulator, they are designed and manufactured for a middle-sized passenger vehicle, and their field-dependent characteristics are experimentally evaluated. The governing equation of motion for the full-vehicle is then established and integrated with the governing equations of the ER suspension and ER brake. Subsequently, a sky-hook controller for the ER suspension and a sliding mode controller for the ER brake are formulated and implemented. Control performances such as vertical displacement and braking distance of vehicle are evaluated under various driving conditions through computer simulations.

• Journal of Power System Engineering
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• v.4 no.1
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• pp.51-59
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• 2000

Active suspension systems have been using for improving ride quality and stability for vehicles. An active suspension system is composed of a hydraulic pump, pressure control valves, hydraulic dampers, vehicle body, tires and other components. In this study, the mathematical model for the active suspension system based on the quarter car concept is derived, and a program for analysing the dynamic behaviour of the suspension system is developed. The computed results by the developed program are compared with the experimental results for confirming the reliability and usefulness of the developed program.

• Journal of Environmental Health Sciences
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• v.21 no.2
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• pp.7-11
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• 1995

This study was carried out to investigate the change of average specific resistance according to filtration pressure, suspension concentration and filters for study phenomena occurring in cake filtration. As the results of this study, the following conclusions were obtained. It was estimated that the average specific resistance of filtration Was decreased in proportion to decreased of filtration pressure. But in very pressure, average specific resistance was increased. The average specific resistance value on filter medium by various pressure was showed as same trends under constant suspension concentration. This phenomenon was though that a carrain amount of fine particles in the cake was found to migrate throught the cake in the case of very thin at very low pressure. In relation to the change of suspension concentration, average specific resistance value become low according to decreased in supension concentration.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.10
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• pp.979-986
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• 2009

This paper presents a dynamic modeling of a military vehicle suspension featuring disc spring and MR valve. Firstly, the dynamic model of the disc spring is established with respect to the load and pressure. The nonlinear behavior of the spring is incorporated with the model. Secondly, the dynamic model of the MR valve is derived by considering the pressure drop due to the viscosity and yield stress of MR fluid. The governing characteristics of the proposed suspension system are then investigated by presenting the field-dependent pressure drop of the MR valve and spring force of the gas spring.

• The Journal of Internal Korean Medicine
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• v.12 no.1
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• pp.1-18
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• 1991

We performed the effect of Woohwangchungsim-won suspension (group A), pills(group B) in patients with circulatory system disease. Total 63 patients were classified into group A and group B. The results obtained were as follows ; 1. The highest effect was showed that group A was blood pressure, group B was anxiety, the lowest effect was showed that group A was insomnia, group B was blood pressure. 2. Generally, pills was somewhat higher than suspension, but suspension was somewhat higher in more than good effect. 3. In depressed blood pressure, group A, group B were 82.6%, 63.6% in fair effect and more respectively. 4. There was no side effect in overall cases.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1159-1165
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• 2011

This paper presents ride comfort characteristics of a quarter-vehicle magneto-rheological(MR) suspension system with respect to different tire pressure. As a first step, controllable MR damper is designed and modeled based on both the optimized damping force levels and mechanical dimensions required for a commercial full-size passenger vehicle. Then, a quarter-vehicle suspension system consisting of sprung mass, spring, tire and the MR damper is constructed. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, vertical tire stiffness with respect to different tire pressure is experimentally identified. The skyhook controller is then implemented for the realization of the quarter-vehicle MR suspension system. Finally, the ride comfort analysis with respect to different tire pressure is undertaken in time domain. In addition, a comparative result between controlled and uncontrolled is provided by presenting vertical RMS displacement.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.3
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• pp.275-280
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• 1999

This paper presents a disturbance accommodating sliding mode control for a quarter-car active suspension using an electro-hydraulic actuator. The electro-hydraulic actuator model is nonlinear and uncertain. The hardware constrains on the actuator prevent high gain in a sliding mode control, which deteriorates the force tracking performance. DAC(Disturbance Accommodating Control) is combined with the sliding mode control to improve the tracking performance. DAC observer estimates the pressure due to the actuator uncertainty. The additional control is designed to compensate the estimated pressure. Simulation results show the improved tracking performance with the Proposed control methods.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.111-118
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• 1998

Surge pressure problem at the oil return line of the hydraulic circuit of an active suspension system for passenger cars was investigated by experiments and numerical analyses. In the numerical analyses, the method of characteristics was used for simulating unsteady flow in the hydraulic system and gas discrete model was adopted for estimating gas volume variation in separated liquid column. In the experiments and analyses, effects of the physical parameters of the accumlator on smoothing surge pressure was elucidated.