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Wang L.,Hunan University | Wang L.,Key Laboratory of Building Safety and Energy Efficiency | Rega G.,University of Rome La Sapienza
International Journal of Solids and Structures | Year: 2010

In this study, the 3D nonlinear equations of motion of the suspended cable with moving mass are obtained via the Hamilton principle, and its transient linear planar dynamics is investigated. Considering the quasi-static assumption, the condensed planar model accounting for the effect of the moving mass is derived, and it is then discretized by choosing the static deflection and sine series as shape functions. It is shown that this expansion shows good convergence features. The Newmark method is used to investigate the transient response. The effects of the inertia force, mass, sag and velocity of the moving mass on the transient dynamics of the suspended cable are systematically investigated. Finally, the horizontal tension of the suspended cable and the case of sequentially moving masses are examined. © 2010 Elsevier Ltd. All rights reserved. Source


Wang L.,Hunan University | Wang L.,Key Laboratory of Building Safety and Energy Efficiency | Ma J.,Hunan University | Peng J.,Hunan University | Li L.,Hunan University
International Journal of Mechanical Sciences | Year: 2013

The nonlinear vibration and parametric instability of the inextensional beam on the elastic foundation are investigated. Considering the inextensional condition and second-order moment of the subgrade reaction, the motion equation of the beam on the elastic foundation is obtained via the Hamilton principle. Then the Galerkin method is applied to obtain the discretized model. The periodic motion is examined by means of the continuation method. Whereas, the numerical simulation is performed to study the nonperiodic motion, particular attention is placed on the nonlinear response of two resonant beams and the parametric instability. Finally, the effects of the boundary conditions and foundation models on the nonlinear vibration of the beams are discussed. © 2012 Published by Elsevier Ltd. All rights reserved. Source


Wang L.,Hunan University | Wang L.,Key Laboratory of Building Safety and Energy Efficiency | Ma J.,Hunan University | Li L.,Hunan University | Peng J.,Hunan University
Journal of Vibration and Acoustics, Transactions of the ASME | Year: 2013

The large amplitude vibrations of the inextensional beam resting on the elastic foundation under three-to-one internal resonance are investigated. The inextensional condition and multimodal discretization are used to obtain the equation of in-plane motion and modulation equations. Due to the second-order moment of the subgrade reaction, the quadratic nonlinearity is included in the present model. Moreover, this moment destroys the conservative character of the system. The nonlinear response and the associated stability are examined by means of frequency (force)-response curves, and the shooting method is applied to investigate the dynamic solutions. Particular attention is placed on the effects of the cut-off frequency and boundary conditions. The results show that the cut-off frequency and boundary conditions do not significantly affect the contribution of nonresonant modes to the nonlinear coefficients. Moreover, the effects of foundation models on the three-to-one resonant dynamics of the beam are discussed. © 2013 American Society of Mechanical Engineers. Source


Wang L.,Hunan University | Wang L.,Key Laboratory of Building Safety and Energy Efficiency | Ma J.,Hunan University | Zhao Y.,Hunan University | Liu Q.,Hunan University
Journal of Applied Mechanics, Transactions ASME | Year: 2013

In this study, the nonlinear equation of motion of the beam on the elastic foundation is obtained via the Newton's second law of motion, and its free vibration nature is investigated. Considering the inextensional condition, the planar model of the beam accounting for the effects of the rotary inertia is derived. Then, the linear vibration and nonlinear vibration of the beam on the elastic foundation are examined. It is shown that the cut-off frequency can be observed in the frequency spectrum of the beam response. The effects of the rotary inertia on the natural frequencies are systematically investigated. Finally, the frequency differences, due to the different foundation models, and the possible modal interaction of the beam are discussed. Copyright © 2013 by ASME. Source


Du C.,Hunan University | Du C.,Key Laboratory of Building Safety and Energy Efficiency | Chen Y.,Hunan University | Chen Y.,Key Laboratory of Building Safety and Energy Efficiency
Renewable Energy | Year: 2011

Analysis of borehole thermal resistance is important for the standard sizing of ground heat exchanger (GHE). In this paper, a p-linear dimensionless average fluid temperature is proposed to estimate borehole thermal resistance. A p-linear dimensionless fluid temperature and p-linear dimensionless average fluid temperature are introduced, and the p-linear dimensionless fluid temperature is compared with theoretical dimensionless fluid temperature calculated by quasi-three-dimensional model for both single and double U-tubes. Results show that the p-linear dimensionless temperatures with parameters p→. 0 and p= -1/2 are respectively in good agreement with the theoretical dimensionless fluid temperatures of single and double U-tubes. Therefore, the dimensionless logarithmic mean temperature for p→. 0 and the dimensionless geometric mean temperature for p= -1/2 should respectively be adopted to reasonably estimate the thermal resistance of single and double U-tube boreholes. © 2010 Elsevier Ltd. Source

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