• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.342-347
• /
• 2003

In this paper, an active vibration control of a translating tensioned string with the use of an electro-hydraulic servo mechanism at the right boundary is investigated. The dynamics of the moving strip is modeled as a string with tension by using Hamilton’s principle for the systems with changing mass. The control objective is to suppress the transverse vibrations of the strip via boundary control. A right boundary control law in the form of current input to the servo valve based upon the Lyapunov’s second method is derived. It is revealed that a time-varying boundary force and a suitable passive damping at the right boundary can successfully suppress the transverse vibrations. The exponential stability of the closed loop system is proved. The effectiveness of the control laws proposed is demonstrated via simulations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.644-647
• /
• 2005

In this paper, computer simulations with the absolute nodal coordinate formulation for large deformation problems in flexible multibody dynamics are compared to the real experiments. A high speed camera was employed to capture the deformed shapes of a thin beam, a plate, a rotating chain, and a paper strip. The measured data was used to calculate precise values for stiffness and damping ratio of the objects. Also a rotating strip and a helicoseir problem were formulated for computer simulation, and the computational results are also compared to the experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.356-359
• /
• 2005

Ionic-polymer-metal-composite(IPMC), one of new actuation materials of electroactive polymers plated with noble metallic electrodes is known for the fast bending upon electric field. The IPMC strip bends towards anode under electrical field. It has many merits of low driving voltage, quick responsiveness, high durability, possibility of miniaturizability. In this paper, we studied for developing the large deflection of IPMC according several fabricating parameters. We measured the large deflection by the different process of sandpaper and sandblasting in surface treatment, the initial compositing process and the surface electroding process, and the different counter ions in ion exchanging process. In fundamental, the displacement of IPMC strip depends on voltage magnitude and applied signal frequency and its maximum deformation is observed at a critical frequency, resonant frequency.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.05a
• /
• pp.780-785
• /
• 2001

A method for accurate measurement of the contact force in the current collection system of the high-speed railway is developed. In order to measure the contact force with minimal modifications to the pantograph, strain gauges are attached to the bottom of the contact strip. An algorithm for deriving the magnitude and stagger of the contact force from the bending strain measurements is devised. For the sample pantograph, the static contact forces are measured to within ${\pm}$5 % error for the magnitude and ${\pm}$ 2cm error for the stagger. For dynamic contact force measurement, it is found that the contact strip can the regarded as a rigid body for the contact frequency of less than 15 ㎐.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.1016-1019
• /
• 2002

This paper deals with a fundamental and classical scattering problem by a finite strip. For the analysis of scattered acoustic field, a “single” integral equation is derived. Firstly, the complexity by considering the effect of the mean flow is alleviated by the introduction of Prandtl-Glauert coordinate and the new dependent variable. Secondly, the difficulty of solving the resultant strongly-coupled integral equations which always appear in this kind of 3-part mixed boundary value problem is solved by observing some good properties of the functions in complex domain and manipulating the equations and variables for the use of those properties. The solution can be obtained asymptotically in terms of gamma function and Whittaker function. One aim of this study is the improvement of methodology for the research using integral equations. The other is the basic understanding of scattering by a finite strip related to the linear cascade model of rotating fan blades.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1854-1858
• /
• 2000

Chattering phenomenon is an abrupt relative vibration between the strip and rolls of rolling machine in working. It inevitably results from the progress of the degeneration in the mill facilities. This research was carried out in order to analyze the characteristic and find the cause of chatter mark in finishing mill and it was founded that one of major cause is appearance of dead zone at pinion stand in case of excessive roll force.

• Proceedings of the KSME Conference
• /
• 2001.06b
• /
• pp.578-583
• /
• 2001

Chattering phenomenon is an abrupt relative vibration between the strip and rolls of rolling machine in working. It inevitably results from the progress of the degeneration in the mill facilities. This research was carried out in order to analyze the characteristic and find the cause of chatter mark in finishing mill and it was founded that major causes are facility character of driving part and special condition in case of excessive roll force.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1993.10a
• /
• pp.145-150
• /
• 1993

본 연구에서는 진동 문제가 심각하게 발생하고 있는 한 압연기를 대상으로 조업중의 진동과 동적 torque의 변화를 동시에 측정하여 이들 data를 여러가 지 해석기법을 통해 분석함으로써, 진동 발생 원인과 mechanism을 규명하고 진동에 미치는 torque 변화의 영향을 알아보고자 한다. 또한 이를 근거로 진 동발생과 설비 손상의 방지 방안을 제시하고자 한다.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2005.04a
• /
• pp.548-555
• /
• 2005

Since soil-structure interactions are one of the most important subjects in the structural/foundation engineering, much study concerning the soil-structure interactions had been carried out. One of typical structures related to the soil-structure interactions is the strip foundation which is basically defined as the beam or strip rested on or supported by the soils. At the present time, lack of studies on dynamic problems related to the strip foundations is still found in the literature. From these viewpoint, this paper aims to theoretically investigate dynamics of the elliptic strip foundations and also to present the practical engineering data for the design purpose. Differential equations governing the free, out-of-plane vibrations of such sap foundations we derived, in which effects of the rotatory and torsional inertias and also shear deformation are included although the warping of the cross-section is excluded. Governing differential equations subjected to the boundary conditions of free-free end constraints are numerically solved for obtaining the natural frequencies and mode shapes by using the numerical integration technique and the numerical method of non-linear equation.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.5
• /
• pp.82-86
• /
• 2013

The automotive weather strip has the functions isolating of dust, water, noise and vibration from outside. The core of weather strip is made of steel with stiffness. By using the wire formed as the core of weather strip, weight can be reduced as much as 35% by comparing with existing steel core. For this reason, forming wire is necessary to keep the zigzag shape as it is. The deformation which is occurred during forming process can be predicted and it can be used in case of manufacturing dies through CAE. In this paper, rolling process conditions are deduced and the springback amount is predicted after rolling process by using the simulation. The springback amount of product is measured by using optical microscope, and measurement result is compared with the simulation result of springback as the same condition. The suitable gap between dies to compensate springback after rolling process is predicted through simulation and it is used for manufacturing dies.