整體上具有間斷質量與剛度變化、端部具有偏心質量及非傳統基礎的部分浸濕的錐形鐵木辛柯梁自由撓曲振動分析

作者：Ankit,N.Datta

摘要：A compliant tower is modeled as a partially dry,partially tapered,damped Timoshenko beam with the superstructure modeled as an eccentric tip mass,and a non-classical damped boundary at the base.The foundation is modeled as a combination of a linear spring and a torsional spring,along with parallel linear and torsional dampers(Kelvin-Voigt model).The superstructure adds to the kinetic energy of the system without affecting the potential energy,thereby reducing the natural frequencies.The weight of the superstructure acts as an axial compressive load on the beam,reducing its natural frequencies further.The empty space factor due to the truss-type structure of the tower is included.The effect of shear deformation and rotary inertia are included in the vibration analysis;with the non-uniform beam mode-shapes being a weighted sum of the uniform beam mode-shapes satisfying the end condition.The weights are evaluated by the Rayleigh-Ritz(RR)method,and verified using finite element method(FEM).The weight of the superstructure acts as an axial compressive load on the beam.Kelvin-Voigt model of structural damping is included.A part of the structure being underwater,the virtual added inertia is included to calculate the wet natural frequencies.A parametric study is done for various magnitudes of tip mass and various levels of submergence.The computational efficiency and accuracy of the Rayleigh-Ritz method,as compared to the FEA,has been demonstrated.The advantage of using closed-formtrial functions is clearly seen in the efficacy of calculating the various energy components in the RR method.

發文機構：School of Civil and Environmental Engineering Department of Ocean Engineering and Naval Architecture

關鍵詞：CompliantTOWERTIMOSHENKObeamRayleigh-RitzmethodECCENTRICTIPmassWetvibrationCompliant towerTimoshenko beamRayleigh-Ritz methodEccentric tip massWet vibration

分類號： T[一般工業技術]