• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.793-798
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• 2004

The vibration of a curved pipe conveying fluid is studied when the pipe is clamped at both ends. To consider the geometric nonlinearity, this study adopts the Lagrange strain theory for large deformation and the extensible dynamics based on the Euler-Bernoulli beam theory for slenderness assumption. By using the extended Hamilton principle, the non-linear partial differential equations are derived for the in-plane motions of the pipe. The linear and non-linear terms in the governing equations are compared with those in the previous study, and some significant differences are discussed. To investigate the vibration characteristics of the system, the discretized equations of motion are derived from the Galerkin method. The natural frequencies varying with the flow velocity are computed from the two cases, which one is the linear problem and the other is the linearized problem in the neighborhood of the equilibrium position. From these results, we should consider the geometric nonlinearity to analyze the dynamics of a curved pipe conveying fluid more precisely.

• 대한기계학회논문집A
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• 제27권11호
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• pp.1815-1823
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• 2003

The vibrational system of this study consists of a cantilever pipe conveying fluid, the moving masses upon it and having an attached tip mass. The equation of motion is derived by using Lagrange's equation. The influences of the velocity and the inertia force of the moving mass and the velocities of fluid flow in the pipe have been studied on the dynamic behavior and the natural frequency of a cantilever pipe by numerical method. The deflection of the cantilever pipe conveying fluid is increased due to the tip mass and rotary Inertia. After the moving mass passed upon the cantilever pipe, the amplitude of pipe is influenced by energy variation when the moving mass fall from the cantilever pipe. As the moving mass increase, the frequency of the cantilever pipe conveying fluid is increased. The rotary inertia of the tip mass influences much on the higher frequencies and vibration mode.

• 대한기계학회논문집A
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• 제37권6호
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• pp.739-745
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• 2013

본 연구에서는 급수 순환 시스템 중 동작 유체의 이송을 위해 사용하는 배관을 대상으로 관로 크기 및 고온 급수 환경에 따른 침식-부식 거동과 그 영향을 규명하고자 하였다. 이를 위해 일반적인 관로 소재인 철과 핵심 부식 인자인 산소의 화학반응식을 기반으로 Hayduk 과 Minhas 가 제안한 모델을 이용하여 침식-부식 해석을 실시하였다. 상용 유한요소해석 프로그램인 ABAQUS 를 사용하여 해석을 수행하였으며 배관의 직경 및 급수 온도를 변화시킴에 따른 침식-부식률을 평가할 수 있었다. 결과를 통해 급수 온도가 침식-부식률에 가장 큰 영향을 미치는 요인이 됨을 알 수 있었으며, 특히 $290^{\circ}C$ 급수에 노출된 스테인리스 316 강은 연간 $2.59{\mu}m$의 두께 손실이 발생할 것으로 예상되었다.