• International Journal of Aeronautical and Space Sciences
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• 제11권1호
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• pp.26-30
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• 2010

The present paper studies the thermally-induced vibration phenomenon of the flexible space boom structure. In order to simulate the thermally-induced vibration phenomenon of the flexible thin boom structure of the spacecraft with the attached tip mass in space, the thermally-induced vibration including thermal flutter is experimentally investigated at various thermal environments using a heating lamp in vacuum chamber. In this experimental study, fluctuating characteristics, natural frequency and thermal strains of the thermally-induced vibration are parametrically investigated at various thermal environment conditions. Finally the thermally-induced vibration of the flexible boom structure of the orbiting earth satellite in solar radiation environment from the earth eclipse region including umbra and penumbra is simulated using the power control of the heating lamp in the vacuum chamber.

• Structural Engineering and Mechanics
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• 제53권3호
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• pp.443-453
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• 2015

Cable-beam structures characterized by variable stiffness nonlinearities are widely found in various structural engineering applications, for example in space deployable structures. Space deployable structures in orbit experience both high temperature caused by sun's radiation and low temperature by Earth's umbral shadow. The space temperature difference is above 300K at the moment of exiting or entering Earth's umbral shadow, which results in structural thermally induced vibration. To understand the thermally induced oscillations, the analytical expression of Boley parameter of cable-beam structures is firstly deduced. Then, the thermally induced vibration of cable-beam structures is analyzed using finite element method to verify the effectiveness of Boley parameter. Finally, by analyzing the obtained numerical results and the corresponding Boley parameters, it can be concluded that the derived expression of Boley parameter is valid to evaluate the occurrence conditions of thermally induced vibration of cable-beam structures and the key parameters influencing structural thermal flutter are the cable stiffness and thickness of beams.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1696-1701
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• 2003

This paper deals with a vibration control analysis of a rotating composite blade, modeled as a tapered thinwalled beam induced by heat flux. The displayed results reveal that the thermally induced vibration yields a detrimental repercussions upon their dynamic responses. The blade consists of host graphite epoxy laminate with surface and spanwise distributed transversely isotropic (PZT-4) sensors and actuators. The controller is implemented via the negative velocity and displacement feedback control methodology, which prove to overcome the deleterious effect associated with the thermally induced vibration. The structure is modeled as a composite thin-walled beam incorporating a number of nonclassical features such as transverse shear, secondary warping, anisotropy of constituent materials, and rotary inertias.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1631-1636
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• 2003

The purpose of this study is to analyze the phenomena of the thermally-induced vibration for the flexible space structure due to abrupt change of radiation heating circumstance using the numerical analyze and experiment test. In order to verify this structure, numerical approaches on the simplified flexible tube were compared with experimental test results at the ground experimental facility In this analyze, it was found that the thermal deformation occurs firstly due to fast radiation heating of flexible structure and then the thermally-induced vibration would be induced due to small periodic change of temperature. According to comparison of numerical and experimental result, in case of no tip mass, the first mode vibration by the numerical analyze was O.78Hz same as that of the experimental result However in case of increase tip-masses of 8g l6g, 50g and 100g, the first modes vibration theoretical analyze were 1.75Hz, 1.3Hz, 0.87Hz and O.73Hz, in decrease trend respectively and those by experimental test were 234Hz, 1.5Hz, O.78Hz and O.78Hz in decrease trend respectively Although using the simpled equation for the estimation, the estimation results were similar to experimental results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.303-310
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• 2002

The bending vibration and thermal flutter instability of spacecraft booms modeled as circular thin-walled beams of closed cross-section and subjected to thermal radiation loading is investigated in this paper. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferantially uniform system(CUS) configuration are exploited in connection with the structural flapwise bending-lagwise bending coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. The numerical simulations display deflection time-history as a function of the ply-angle of fibers of the composite materials, damping factor, incident angle of solar heat flux, as well as the boundary of the thermal flutter instability domain. The adaptive control are provided by a system of piezoelectric devices whose sensing and actuating functions are combined and that an bonded or embedded into the host structure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.399-406
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• 2001

Thermally induced vibration response of composite thin walled beams is investigated. The thin-walled beam model incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, rotary inertia and anisotropy of constituent materials. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferentially uniform system(CUS) configuration are exploited in connection with the structural bending-torsion coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1216-1221
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• 2000

Thermally induced vibration response of composite thin walled beams is investigated. The thin-walled beam model incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, 'rotary inertia' and anisotropy of constituent materials. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferentially uniform system(CUS) configuration are exploited in connection with the structural coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated.

• 한국항공우주학회지
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• 제30권1호
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• pp.56-64
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• 2002

본 논문에서는 복합재료 얇은 벽보의 열진동 응답에 대해 연구하였다. 복합재료 얇은 벽보로 모델링한 위성체 유연 구조물은 회전관성과 1차, 2차 와핑. 전단변형의 비고전적 요소를 포함한다. CUS구조물로 모델링한 복합재료 얇은 벽보의 열진동 특성은 적층순서와 섬유강화복합재료의 방향특성인자로부터 기인된 종방향 굽힘과 횡방향 굽힘이 연성과 관련하여 연구되었다. 열에 의한 구조물의 변형과 온도 구배가 연성된 열 진동에 대한 해석이 수행되었다.

• 한국항공우주학회지
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• 제31권9호
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• pp.46-54
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• 2003

본 연구의 목적은 유연 우주구조물이 급격한 열적 환경에 의해 발생되는 진동을 수치적인 계산과 실험을 통해 규명하는데 있다. 단순화한 유연 구조물에 대해 수치적인 접근과 지상 실험실에서 실험한 데이터를 비교 분석하였다. 분석결과 유연 구조물이 급속한 복사 열에 의해 열적 모멘트에 의한 열적 변위가 발생하고 온도의 미소한 주기적 변화로 열 유기 진동이 발생함이 밝혀졌다. 수치해석치와 실험치를 비교한 결과 끝단질량이 없는 경우, 1차 모드 진동수는 0.78Hz로 두 값이 일치하였으나, 끝단 질량이 있는 경우, 끝단 질량이 각각 8g, 16g, 50g, 100g으로 증가할 때 1차 모드의 진동수에 있어 예측치는 1.75Hz, 1.3Hz, 0.87Hz, 0.73Hz이고 실험치는 2.34Hz, 1.5Hz, 0.78Hz, 0.78Hz로 감소하는 경향을 보이며 비록 예측치가 단순화 공식을 이용함에도 불구하고 실험치에 근접하였다.

• Structural Engineering and Mechanics
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• 제68권3호
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• pp.313-323
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• 2018

A numerical study is performed to investigate the impacts of thermal loading on the vibration and buckling of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) conical shells. Thermo-mechanical properties of constituents are considered to be temperature-dependent. Considering the shear deformation theory, the energy functional is derived, and applying the variational differential quadrature (VDQ) method, the mass and stiffness matrices are obtained. The shear correction factors are accurately calculated by matching the shear strain energy obtained from an exact three-dimensional distribution of the transverse shear stresses and shear strain energy related to the first-order shear deformation theory. Numerical results reveal that considering temperature-dependent material properties plays an important role in predicting the thermally induced vibration of FG-CNTRC conical shells, and neglecting this effect leads to considerable overestimation of the stiffness of the structure.