• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.7
• /
• pp.723-728
• /
• 2011

Since the performance of a vacuum circuit breaker (VCB) mainly depends on the spring operating mechanism, an analysis of the spring operating mechanism is required in order to improve the design of a VCB. In this study, the static stiffness of the spring was determined by using a material testing machine, and the test results were used to model the spring through computer simulation. The multi-body dynamic model of the spring was established by using the RecurDyn program. The dynamic model was verified by comparing the results of stem displacements and rotating angles of the brake shaft obtained from the simulation and from the experiments. After verification of the dynamic model of VCB, the cam profile of the VCB was optimized through multi-body dynamics simulation in order to improve the performance of the closing mechanism.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.10
• /
• pp.1034-1042
• /
• 2009

In this paper, the magic formula model was applied for a friction damper in a drum-type washing machine. To describe characteristics of the hysteretic damping force, Physical tests were first carried out to get experimental results using an MTS machine. Then, parameters for the magic formula model were determined from the experimental curves. The ADAMS and MATLAB programs were used for the multibody modeling of the damper and process for parameter identification. The model of drum-type washing machine was applied for a dynamic model of friction damper, in which the accuracy of the proposed damper model was verified.

• Journal of the Korean Society of Systems Engineering
• /
• v.11 no.2
• /
• pp.75-83
• /
• 2015

This paper describes modeling & simulation(M&S) model for dynamic analysis of helicopter rotor blades. Simulation model is developed using Dymola tool which implements the open source language - Modelica. Modelica is appropriate for developing multibody dynamic analysis model. To develop an M&S model efficiently, model based systems engineering(MBSE) is applied. Some diagrams such as requirement diagram, block definition diagram and sequence diagram etc. are drawn to capture the concept of M&S model. This activity is done utilizing the open source tool - Papyrus.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.772-775
• /
• 2003

A bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the force applied to the shaft and the relative deformation of a bushing is nonlinear and exhibits features of viscoelasticity. A force-displacement relation for bushings is important for multibody dynamics numerical simulations. For the nonlinear viscoelastic axial response, Pipkin-Rogers model, the direct relation of force and displacement, has been derived from Lianis model and the sinusoidal input was used for Pipkin-Rogers model, and the affection of displacement with frequency change was studied with Pipkin-Rogers model.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.474-478
• /
• 2004

A bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the force applied to the shaft and the relative deformation of a bushing is nonlinear and exhibits features of viscoelasticity. A force-displacement relation for bushings is important for multibody dynamics numerical simulations. For the nonlinear viscoelastic axial response, Pipkin-Rogers model, the direct relation of force and displacement, has been derived from Lianis model and the sinusoidal input was used for Pipkin-Rogers model, and the affection of displacement with frequency change was studied with Pipkin-Rogers model.

• Journal of the Society of Naval Architects of Korea
• /
• v.47 no.3
• /
• pp.421-429
• /
• 2010

In this paper, in order to analyze the dynamic response of a floating crane when it lifts a heavy cargo, the boom of the floating crane is considered as an elastic beam. The boom is divided into elements based on finite element formulation and the floating frame of reference formulation and nodal coordinates are employed to model the boom as a flexible body. As an extension of the previous study, in order to consider spatial motion in waves, the coupled equations of motions of the 6 degree of freedom (DOF) floating crane and 6 DOF cargo are developed based on the flexible multibody system dynamics. The 3 dimensional deformation of the elastic boom is considered with 18 DOF. The dynamic simulation of the floating crane and the cargo is performed under regular wave conditions with various cargo weights. Finally, the effects of the elastic boom on lifting cargo are discussed by comparing the simulation results between the elastic boom and a rigid boom.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.12
• /
• pp.25-34
• /
• 2006

In this paper, a method of designing the pitch control algorithm for the wind turbine generator system (WTGS) and results of nonlinear simulation are presented. For this, the WTGS is treated as a multibody system and the blade element and momentum theory are adopted to model the aerodynamic force and torque acting the rotor blades. For the purpose of controller design, the WTGS is approximated to 1 DOF system using the fact that the WTGS is eventually a constrained multibody system. Then a classical PID controller is designed and used to regulate the rotational speed of the generator. FORTRAN based nonlinear simulation program is written and used to evaluate the performance of the proposed controller at the various wind scenario and operational modes.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.1
• /
• pp.152-159
• /
• 2005

The dynamic properties between catenary and pantograph of high-speed train are very important factors to affect the stable electric power supply. So as to design the reliable current collection system, a multibody simulation model is needed. In this paper, the dynamic analysis method for a pantograph-catenary cable system of high-speed train is presented. The very deformable motion of a catenary cable is demonstrated using nonlinear continuous beam theory, which is based on an absolute nodal coordinate formulation, and the pantograph is modeled as a rigid multibody. The proposed method might be very efficient, because this method can present the nonlinear properties of a flexible catenary cable and set a various boundary conditions.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.11
• /
• pp.176-184
• /
• 2000

Recently, it becomes a very important issue to consider the mechanical systems such as high-speed vehicle and railway train moving on a flexible beam structure. Using general approach proposed in the first part of this paper, it tis possible to predict planar motion of constrained mechanical system and elastic structure with various kinds of foundation supporting condition. Combined differential-algebraic equations of motion derived from both multibody dynamics theory and Finite Element Method can be analyzed numerically using generalized coordinate partitioning algorithm. To verify the validity of this approach, results from simply supported elastic beam subjected to a moving load are compared with exact solution from a reference. Finally, parameter study is conducted for a moving vehicle model on a simply supported 3-span bridge.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.3
• /
• pp.329-335
• /
• 2014

A maglev vehicle of middle-low speed subjected to both a lift force and a guidance force by a U-shaped single electromagnet is operated over a curved guideway without a guidance controller. Therefore, it is required to carefully decide the curve shape for preventing contact between the vehicle and the guiderail for the case that a Maglev vehicle is operated over a curved guideway with a small radius. Specifically, the shape of the transition curve is very important from the stability viewpoint. This study analyzes the influence of curve shape on maglev stability through parametric composition of the transition curve during vehicle guidance. To this end, a multibody dynamics-based threedimensional Maglev vehicle model was developed. The model was integrated with the vehicle, curved guideway, electromagnets, and their controllers. Using this model, a realistic parametric study including the curved guideway was carried out. The results of research should be considered usefully in the design of bogies and the curve shape.