• Title/Summary/Keyword: 거대질량법

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Numerical Tests of Large Mass Method for Stress Calculation of Euler-Bernoulli Beams Subjected to Support Accelerations (지지점 가속도에 의해 가진되는 보의 응력계산에 대한 거대질량법의 정확도)

  • Kim, Yong-Woo;Choi, Nam Seok;Jhung, Myung Jo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.188-193
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    • 2013
  • The large mass method for dynamic analysis of statically determinate beams subjected to in-phase support motions is justified by showing that the equation of motion of the beams under consideration is equivalent to that of large mass model of the beam when an appropriate large mass ratio is employed. The accuracy of the stress responses based on the beam large mass method is investigated through careful numerical tests. The numerical results are compared to analytic solutions and the comparison shows that the large mass method yields not only the time history of motion but also the distributions of bending moment and shear force accurately.

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Review of Acceleration Methods for Seismic Analysis of Through-Wall Cracked Piping from the Viewpoint of Linear Elastic Fracture Mechanics (지진 해석시 선형탄성파괴역학 측면에서의 관통 균열 배관에 대한 가진 방법론 검토)

  • Kim, Jong Sung;Kim, Yong Woo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.10
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    • pp.1157-1162
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    • 2014
  • Two acceleration methods, an effective force method (or inertia method) and a large mass method, have been applied for performing time history seismic analysis. The acceleration methods for uncracked structures have been verified via previous studies. However, no study has identified the validity of these acceleration methods for cracked piping. In this study, the validity of the acceleration methods for through-wall cracked piping is assessed via time history implicit dynamic elastic seismic analysis from the viewpoint of linear elastic fracture mechanics. As a result, it is identified that both acceleration methods show the same results for cracked piping if a large mass magnitude and maximum time increment are adequately selected.

Shock Analysis of Gimbal Structure System Including Rubber Vibration Isolator in a Observation Reconnaissance Aircraft (방진 고무를 포함한 항공 감시 정찰용 짐발 구조 시스템의 충격 해석)

  • Lee, Sang Eun;Lee, Tae Won;Kang, Yong Goo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.2
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    • pp.73-80
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    • 2014
  • A camera module that gathers visual information via aerial observation reconnaissance is equipped inside a gimbal structure. This gimbal structure system must reduce dynamic responses in order to obtain clear images under all circumstances. Among many design specifications for this system, there is MIL-STD-810G as a shock standard. This specification indicates a limitation of the acceleration of the camera module under a base shock excitation on the gimbal structure. The satisfaction of this condition can usually be proved by experiment, because it includes bearings and dynamic isolators made of rubber. Numerical analysis must be proposed for design improvement of the gimbal structure. To achieve this goal, transient response analysis for the base shock excitation was performed using the finite element method. Experimental results were compared with numerical solutions and it is shown that the present method is useful.