• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.4
• /
• pp.405-413
• /
• 2010

The vibration characteristics of fully and partially embedded piles with flexibly supported end carrying an eccentric tip mass are investigated. The pile model is based on the Bernoulli-Euler theory and the soil is idealized as a Winkler model for mathematical simplicity. The governing differential equations for the free vibrations of such members are solved numerically using the corresponding boundary conditions. The lowest three natural frequencies and corresponding mode shapes are calculated over a wide range of non-dimensional system parameters: the rotational spring parameter, the relative stiffness, the embedded ratio, the mass ratio, the dimensionless mass moment of inertia, and the tip mass eccentricity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.477-482
• /
• 2003

A nonlinear modeling method for an axially oscillating cantilever beam with a concentrated mass is presented in this paper. Hybrid deformation variables are employed fur the modeling method with which frequency response characteristics of axially oscillating cantilever beams are investigated. The geometric nonlinear effects of stretching and curvature are considered to accurately predict the frequency response characteristics of the oscillating cantilever beam. The effects of the magnitude and the location on the concentrated mass on the frequency characteristics are investigated. It is found that the dynamic instability is significantly influenced by the two parameters.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2010.04a
• /
• pp.285-288
• /
• 2010

유체저장탱크가 외부로부터 지진과 같은 동적하중을 받게 될 경우 유체와 구조물의 상호작용(Fluid-Structure Interaction)으로 인하여 일반적인 구조물과는 상이한 거동을 보이게 된다. 이러한 복잡한 상호작용을 고려하여 현재 내진 설계에서는 Housner와 Haroun의 이론을 적용한 단순화 모델들이 사용되고 있다. 이들 모델은 유체의 거동을 대류(convective) 성분과 충격(impulsive) 성분으로 구분하여 집중질량으로 단순화 한다. 하지만 점차 대형화되고 있는 유체저장탱크의 정확한 동적 거동 특성을 파악하고, 지진하중과 같은 방향성을 가진 하중에 대한 구조물의 정확한 응답을 해석하려면 단순화 모델의 적용성 검토가 필요하다. 본 연구에서는 지진하중을 받는 유체저장탱크의 동적거동을 집중질량 모델과 3차원 모델을 이용하여 해석하였다. 나아가 해석결과의 차이를 분석하여 단순화 모델의 정확도 향상을 위한 내진설계변수 산출에 관하여 향후 연구방향을 제시하였다.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.13 no.3
• /
• pp.554-560
• /
• 1989

An optimal design technique is used as a systematic approach to analyze the worst case of a circulating type ropeway for a given geometry and operating conditions. Worst case is meant here the case when the positions and weights of the cars are so conditioned that the minimum of all the reaction forces between the main rope and the towers is minimum. In the course of this study, a general theory for the deflections and tensions of the main rope were also derived taking into account of the variation of the weights and positions of the individual cars. And through an analysis of example ropeways, some general conditions for the worst case are deduced.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.04a
• /
• pp.502-503
• /
• 2013

• Bulletin of the Society of Naval Architects of Korea
• /
• v.20 no.3
• /
• pp.33-38
• /
• 1983

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.11 s.104
• /
• pp.1287-1294
• /
• 2005

The purpose of this paper is to investigate free vibrations and critical loads of the Beck's columns with a tip spring, which carry a tip mass. The ordinary differential equation governing free vibrations of Beck's column subjected to a follower force is derived based on the Bernoulli-Euler beam theory Both the divergence and flutter critical loads are calculated from the load-frequency corves that are obtained by solving the differential equation numerically. The critical loads are presented in the figures as functions of various non-dimensional system parameters such as the subtangential parameter, mass ratio and spring parameter.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.11 no.1
• /
• pp.124-131
• /
• 1987

The parameteric instability of the cantilever beam carrying two concentrated masses subjected to a periodic follower force is investigated theoretically and experimentally. The effects of the constant follower force and the periodic follower force the mass ratio and the location of the concentrated mass on the parametric instability of the system are discussed. In experiment, the nonconservative follower force is produced by the magnetic force of the electromagnet. The theoretical and the experimental results on the parameteric instability are in good agreement each other.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.13 no.11
• /
• pp.868-874
• /
• 2003

A nonlinear modeling method for an axially oscillating cantilever beam with a concentrated mass is presented in this paper. Hybrid deformation variables are employed for the modeling method with which frequency response characteristics of axially oscillating cantilever beams are investigated. The geometric nonlinear effects of stretching and curvature are considered to accurately predict the frequency response characteristics of the oscillating cantilever beam. The effects of the size and the location of the concentrated mass on the frequency characteristics are investigated. It is found that the dynamic instability is significantly influenced by the two parameters.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.7 no.4 s.19
• /
• pp.114-124
• /
• 2004

In this paper, we have proposed a novel method which can analysis a rotating elastically restrained blade with concentrated masses located in an arbitrary position. 1:he equations of motion are derived and transformed into a dimensionless form to investigate general phenomena. For the modeling of the multi-concentrated masses, the Dirac delta function is used for the mass density function. Simulation results show that the vibration characteristics of elastic restrained blade of according to dimensionless variables for example, multiple masses magnitude and mass location ratio. This method can be applied to an practical rotating blade system required to more accurate results.