• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.1210-1215
• /
• 2002

The spent fuel handling tool is used to handle the refuel bundle and treated by hoist rope on the bridge crane. The new developed handling tool of NPP(Nuclear Power Plant) should be conformed the structural stability under earthquake condition. In this study, the stress and seismic analysis of the handling tool are performed by finite element method. Using the Floor Response Spectrum(FRS) obtained through the time history analysis, the modal and seismic analysis under Operating Basis Earthquake(OBE) and Safe Shutdown Earthquake(SSE) load conditions are carried out. Total 4 cases of different locations of the trolly and the hook are investigated. With the spring-damper element, the tension analysis of hoist rope is conducted. The stability of handling tool under earthquake load condition is conformed with regulatory guide.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.5
• /
• pp.112-119
• /
• 2001

A variety of input shaper has been proposed to reduce the residual vibration of flexible structures. Multi-hump input shaper is known to be robust for parameter variations. However, existing approach should solve the more complicated nonlinear simultaneous equations to improve the robustness of the input shaper with the additional constraints. In this paper, by proposing a graphical approach which uses convolution of shaper, the multi-hump convolution input shaper could be designed even if the constraints are added for further robustness. With a mass-damper-spring model, the better performance is obtained using the proposed new multi-hump convolution input shaper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.04a
• /
• pp.121-127
• /
• 1997

Normal operation of a workstation in a ship must be secured under any circumstances. Rugged workstation has been imported and there have been many difficulties in maintaining that system such as high cost, delayed after-service and etc. For that reason, a commercial workstation is decided to replace the rugged workstation. But as there is no anti-vibration design in the commercial workstation, a passive vibration isolation system consisted with oil damper and spring is applied. Through theoretical study and experiments, the proposed vibration system is proved to work effectively and make the commercial workstation be able to be used in a ship.

• Journal of KSNVE
• /
• v.10 no.5
• /
• pp.865-872
• /
• 2000

This paper presents the modeling, theoretical formulation, and stability analysis for a combined system of a spinning disc and a head that contacts the disc. In the analytic model, head interference is considered by a rotating mass-spring-damper system together with a frictional follower force on the damped annular discs. The multiple scale method is utilized to perform the stability system that shows the existence of instability associated with parametric resonances. Using the formulated system , instability regions of optical recording disc are investigated with variation of mass, stiffness and friction force of a head, respectively. The simulation results show that the stiffness of a head is the most sensitive parameter on the instability of the disc.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.9
• /
• pp.731-737
• /
• 2002

Nonlinear vibration of the CRT shadow mask with impact damping wires is analyzed in consideration of the mask tension distribution and the effect of wire impact damping. A reduced order FEM model of the shadow mask is obtained from dynamic condensation of the mass and stiffness matrices, and damping wire is modeled using the lumped parameter method to effectively describe its contact interactions with the shadow mask. The nonlinear contact-impact model is composed of spring and damper elements, of which parameters are determined from the Hertzian contact theory and the restitution coefficient, respectively. The analysis model of the shadow mask with damping wires is experimentally verified through impact tests of shadow masks performed in a vacuum chamber.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.2
• /
• pp.193-200
• /
• 2002

Simple spring-damper-mass models have been widely used to investigate whole-body vortical biodynamic response characteristics of the seated vehicle driver. Most previous models have not considered the effect of wobbling masses; i.e. heart, lungs, liver, intestine, etc. In this study, 4 -DOF seated driver model including one non-rigid mass representing wobbling visceral mass, 5-DOF model including intestine, and 10-DOF model including five lumbar vertebral masses were proposed. The model parameters were identified by a combinatorial optimization technique. simulated annealing method. The objective function was chosen as the sum of error between model response of seat-to-head transmissibility and driving point mechanical impedance and those of experimental data for subjects seated erect without backrest support. The model response showed a good agreement with the experimental response characteristics. Using a 10-DOF model, calculated resonance frequency of lumbar spine at 4Hz was matched well with experimental results of Panjabi et al.

• Proceedings of the KSR Conference
• /
• 1999.05a
• /
• pp.151-158
• /
• 1999

In this study, we developed the simulation program of an overhead catenary-pantograph system, The overhead catenary is modeled with point mass and the pantograph is replaced with 3 d. o. f. model which is composed of mass, spring and damper. Using the developed program, we analyzed the static structure of the overhead catenary and the dynamic characteristics of an overhead catenary-pantograph system such as uplift displacement of contact wire and contact force. we compared the analysis results with the results of GASENDO software developed at RTRI in Japan. The behaviors of uplift displacement of contact wire and contact force were similar with the results of GASENDO software.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.8
• /
• pp.639-647
• /
• 2002

The nonlinear vibration of the thin perforated plate is analyzed in consideration of the V-shaped tension distribution and the effect of wire impact damping. The reduced order FEM model of the tension plate is obtained from dynamic condensation for the mass and stiffness matrices. Tension wire is modeled using the lumped parameter method to effectively describe its contact interactions with the plate. The nonlinear contact-impact model is composed of spring and damper elements, of which parameters are determined from the Hertzian contact theory and the restitution coefficient, respectively. From the evaluation of the computational accuracy and computation time for the deduced impact stiffness and damping coefficient, we determined proper values for the simulation works, accounting for the computational accuracy as well as the computational efficiency. Finally we discussed the results of nonlinear nitration analysis for variations of their design parameters.

• Journal of the Korea Society for Simulation
• /
• v.2 no.1
• /
• pp.78-90
• /
• 1993

기존의 모의 실험언어를 이용해서 연속 체계를 모의 실험하는 것을 사용자가 언어에서 요구하는 형태로 모델을 형성해야 하는 어려움이 따른다. 따라서 본 연구에서는 사용자에게 최대한 편의성을 제공하는 연속체계 모의 실험언어인 PCSL (Postech Continuous -system Simulation Language)를 개발하였다. PCSL은 주어진 대상을 모델링한 미분방정식과 그것을 푸는데 필요한 여러 가지 제약 사항으로 이루어진 간단한 프로그램을 입력으로 받아 자동으로 모의 실험을 수행함으로서 사용자의 노력이 최소화하게 된다. PCSL 처리 시스템의 구성은 주어진 모델을 C 프로그램으로 변형하는 변환기, 모의 실험 알고리즘을 구현한 C 프로그램을 생성하는 생성기, 모의 실험을 수행하는 실행기, 사용자 인터페이스 등으로 되어있다. 구현 예로는 먼저 선형 상미분방정식의 예로 mass-damper-spring system, 비선형 상미분방정식의 예로 van der Pol 방정식, 연립 상미분방정식의 예로는 mixing tank problem 등을 보였다.

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2804-2807
• /
• 2000

This paper suggests a method of the forward dynamic analysis for the computer simulation on the analysis of the dynamic behavior for biped walking robot. The equations f motion of the system or the simulation are constructed by using the Method of the multibody dynamics which is powerful method for modeling of the complex biped system. For the simplicity of simulation, we consider that the sole of the contacting foot is affected by the reaction forces for tree structure system topology instead of the addition or deletion of the kinematic constraints. The ground reaction forces can be modeled using the simple spring and damper model at the three contacting points on the sole of the foot. For minimizing the errors of numerical integration, the number of equations of motion is minimized by adding the driving constraints or a controller instead of the direct driving torques.