For a building structure subjected to impulsive loading, particularly shock and impact loading , the response of the critical columns is crucial to the behaviour of the entire system during and after the blast loading...For a building structure subjected to impulsive loading, particularly shock and impact loading , the response of the critical columns is crucial to the behaviour of the entire system during and after the blast loading phase. Therefore, an appropriate evaluation of the column response and damage under short-duration impulsive loading is important in a comprehensive assessment of the performance of a building system. This paper reports a dynamic analysis approach for the response of RC columns subjected to impulsive loading. Considering that the dynamic response of a column in a frame structure can also be affected by the floor movement which relates to the global vibration of the frame system, a generic column-mass model is used, in which a concentrated mass is attached to the column top to simulate the effect of a global vibration. To take into account the high shear effect under impulsive load, the model is formulated using Timoshenko beam theory, and three main nonlinear mechanisms are considered. Two typical scenarios, one under a direct air blast loading, and another under a blast-induced ground excitation, are analyzed and the primary response features are highlighted.展开更多
In this paper, nonlinear transverse vibrations of axially moving Timoshenko beams with two free ends are investigated. The governing equations and the associated boundary conditions are derived by the extended Hamilto...In this paper, nonlinear transverse vibrations of axially moving Timoshenko beams with two free ends are investigated. The governing equations and the associated boundary conditions are derived by the extended Hamilton principle. The method of multiple scales is applied to analyze the nonlinear partial differential equation. The natural frequencies and modes are investigated by performing the complex mode approach. The effect of natural frequencies with the stiffness and the axial speeds are numerically demonstrated. The solvability conditions are established for the cases of without and with 3:1 internal resonances. The relationships between the nonlinear frequencies and the initial amplitudes at different axial speeds and the nonlinear coefficients are showed for the case of without internal resonances. The effects of the related coefficients are demonstrated for the case of 3:1 internal resonances.展开更多
文摘For a building structure subjected to impulsive loading, particularly shock and impact loading , the response of the critical columns is crucial to the behaviour of the entire system during and after the blast loading phase. Therefore, an appropriate evaluation of the column response and damage under short-duration impulsive loading is important in a comprehensive assessment of the performance of a building system. This paper reports a dynamic analysis approach for the response of RC columns subjected to impulsive loading. Considering that the dynamic response of a column in a frame structure can also be affected by the floor movement which relates to the global vibration of the frame system, a generic column-mass model is used, in which a concentrated mass is attached to the column top to simulate the effect of a global vibration. To take into account the high shear effect under impulsive load, the model is formulated using Timoshenko beam theory, and three main nonlinear mechanisms are considered. Two typical scenarios, one under a direct air blast loading, and another under a blast-induced ground excitation, are analyzed and the primary response features are highlighted.
基金supported by the National Outstanding Young Scientists Foundation of China (Grant No. 10725209)the National Natural Science Foundation of China (Grant No. 90816001)+3 种基金Shanghai Subject Chief Scientist Project (Grant No. 09XD1401700)Innovation Foundation for Graduates of Shanghai University (Grant No. A.16-0401-08-005)Shanghai Leading Academic Discipline Project (Grant No. S30106)the Program for Changjiang Scholars and Innovative Research Team in University (Grant No. IRT0844)
文摘In this paper, nonlinear transverse vibrations of axially moving Timoshenko beams with two free ends are investigated. The governing equations and the associated boundary conditions are derived by the extended Hamilton principle. The method of multiple scales is applied to analyze the nonlinear partial differential equation. The natural frequencies and modes are investigated by performing the complex mode approach. The effect of natural frequencies with the stiffness and the axial speeds are numerically demonstrated. The solvability conditions are established for the cases of without and with 3:1 internal resonances. The relationships between the nonlinear frequencies and the initial amplitudes at different axial speeds and the nonlinear coefficients are showed for the case of without internal resonances. The effects of the related coefficients are demonstrated for the case of 3:1 internal resonances.
