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Shafting coupled vibration Research Based on Wave Approach

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Journal of Shanghai Jiaotong university(Science) 2014年第3期19卷 325-336页

作者：杨勇车驰东唐文勇 State Key Laboratory of Ocean Engineering Shanghai Jiaotong University Marine Design & Research Institute of China

Because of propeller hydrodynamic influence, the shafting vibration is a coupled vibration which includes torsional, longitudinal and whirling vibrations. It is unsuitable to analyze different vibrations of propulsive shafting systems with development of shipbuilding technologies. To overcome the shortages of traditional marine standards, we establish a new numerical model of the shafting coupled vibration. And we put forward shafting coupled vibration calculation to ensure better reliability of main propulsion system. The shafting system is modeled into two sub-systems, a continuous one and a discrete one. Wave approach and transit matrix method are used to investigate displacement and stress fields in continuous and discrete sub-systems, respectively. And vibrations of different modes in both sub-systems are coupled by using dynamic equilibrium and continuity condition to deduce the global equations governing the motion of shafting. The coupling calculation is then used to research the reason of a very large crude carrier(VLCC) stern hull vibration. It is shown by the comparison of the results from both coupling and dependent vibration calculations that vibration in deferent directions will cause deformation in the same mode, which leads to extra stress and displacements on shafting, especially as the resonant frequencies of different vibration modes match each other. This is helpful to prevent ship stern vibration due to poor shafting vibration calculation.

关键词： shafting coupled vibration wave approach resonance

Development of design charts to predict the dynamic response of pile supported machine foundations

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 663-679页

作者： Deepthi SUDHI Sanjit BISWAS Bappaditya MANNA Department of Civil Engineering National Institute TechnologyWarangal 506004India Department of Civil Engineering Indian Institute of TechnologyDelhi 110016India

This paper proposes design charts for estimating imperative input parameters for continuum approach analysis of the nonlinear dynamic response of *** and analytical studies using continuum approach have been conducted on single and 2×2 grouped piles under coupled and vertical modes of vibration,for different dynamic forces and pile *** these design charts are derived from model piles,the charts have been validated for prototype pile foundations using scaling *** experimental responses of model piles are scaled up and these responses exhibit good agreement with analytical *** study also extends to estimation of the errors in computing frequency–amplitude responses with an increase in pile *** is found that,with an increase in pile length,the errors also *** effectiveness of the proposed design charts is also checked with data based on different field setups given in existing literature,and these charts are found to be ***,the developed design charts can be beneficial in estimating the input parameters for continuum approach analysis for determining the nonlinear responses of pile supported machine foundations.

关键词： pile foundation vertical vibration coupled vibration continuum approach soil-pile separation boundary zone parameters

Investigation of block foundations resting on soil-rock and rock-rock media under coupled vibrations

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维普期刊数据库

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第2期9卷 305-317页

作者： Renuka Darshyamkar Ankesh Kumar Bappaditya Manna Department of Civil Engineering Indian Institute of Technology DelhiHauz KhasNew Delhi110016India

In the present study,the dynamic response of block foundations of different equivalent radius to mass（R;/m） ratios under coupled vibrations is investigated for various homogeneous and layered *** frequency-dependent stiffness and damping of foundation resting on homogeneous soils and rocks are determined using the half-space *** dynamic response characteristics of foundation resting on the layered system considering rock-rock combination are evaluated using finite element program with transmitting *** versus amplitude responses of block foundation are obtained for both translational and rotational motion.A new methodology is proposed for determination of dynamic response of block foundations resting on soil-rock and weathered rock-rock system in the form of equations and *** variations of dimensionless natural frequency and dimensionless resonant amplitude with shear wave velocity ratio are investigated for different thicknesses of top soil/weathered rock *** dynamic behaviors of block foundations are also analyzed for different rock-rock systems by considering sandstone,shale and limestone underlain by *** variations of stiffness,damping and amplitudes of block foundations with frequency are shown in this study for various rock—rock *** the analysis,two resonant peaks are observed at two different frequencies for both translational and rotational *** is observed that the dimensionless resonant amplitudes decrease and natural frequencies increase with increase in shear wave velocity ***,the parametric study is performed for block foundations with dimensions of 4 m × 3 m × 2 m and 8m×5m×2m by using generalized *** variations of natural frequency and peak displacement amplitude are also studied for different top layer thicknesses and eccentric moments.

关键词： Rock-rock system Block foundation coupled vibration Homogeneous medium Equivalent radius to mass ratio Half-space theory

Nonlinear modal coupling in a T-shaped piezoelectric resonator induced by stiffness hardening effect

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Applied Mathematics and Mechanics(English Edition) 2022年第6期43卷 777-792页

作者： Lei LI Hanbiao LIU Jianxin HAN Wenming ZHANG School of Transportation and Vehicle Engineering Shandong University of TechnologyZibo 255049Shandong ProvinceChina State Key Laboratory of Mechanical System and vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Tianjin Key Laboratory of High Speed Cutting and Precision Machining Tianjin University of Technology and EducationTianjin 300222China

The nonlinear modal coupling in a T-shaped piezoelectric resonator,when the former two natural frequencies are away from 1:2,is *** sweeping up the exciting frequency shows that the horizontal beam exhibits a nonlinear hardening *** first primary resonance of the vertical beam,owing to modal coupling,exhibits an abrupt amplitude increase,namely the Hopf *** frequency comb phenomenon induced by modal coupling is measured experimentally.A Duffing-Mathieu coupled model is theoretically introduced to derive the conditions of the modal coupling and frequency comb *** results demonstrate that the modal coupling results from nonlinear stiffness hardening and is strictly dependent on the loading range and sweeping form of the driving voltage and the frequency of the piezoelectric patches.

关键词： coupled vibration resonator nonlinear dynamics bifurcation hardening behavior frequency comb

vibration reduction for a new-type maglev vehicle with mid-mounted suspension under levitation failure

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Science China(Technological Sciences) 2023年第12期66卷 3475-3487页

作者： ZHANG Min LIU Jing CAO Yi CHEN XianFa MA WeiHua State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China

Levitation failure occasionally occurs when a maglev vehicle runs on a track. At the moment of levitation failure, the levitation module falls and hits the track, and there is a violent impact on the maglev vehicle-bridge coupled system. In this paper, the response of the maglev vehicle-bridge coupled system at the moment of and after levitation failure is analyzed, and three methods of reducing the vibration are proposed. First, a dynamics model of the maglev vehicle-bridge coupled system, which considers the control system, five flexible bridges, and track irregularity, is established, and the correctness of the model is verified using test data. The system response for different failure cases is then analyzed. Finally, the three methods of reducing vibration under levitation failure are proposed, and their effectiveness is evaluated. The results show that the failure position and speed barely affect the response, whereas the maximum impact forces due to levitation failure reduced by 13%, 63%, and 50% by adopting the three methods, namely connecting the first and third coils in series, coupling the ends of the levitation module vertically, and adopting two sets of anti-roll devices, respectively. When the latter two schemes are combined, the maximum impact force reduced from 133 kN(without vibration-reduction measures) to 9 kN, and the vibration-reduction measure is also effective for failures of the levitation units at the ends of the vehicle.

关键词： mid-and low-speed maglev vehicle maglev vehicle with mid-mounted suspension coupled vibration levitation failure vibration reduction

Analysis on vibration characteristics of large-size rectangular piezoelectric composite plate based on quasi-periodic phononic crystal structure

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Chinese Physics B 2022年第5期31卷 438-447页

作者：胡理情王莎林书玉 Shaanxi Key Laboratory of Ultrasonics Institute of Applied AcousticsShaanxi Normal UniversityXi’an 710119China

Based on the theory of composite materials and phononic crystals(PCs),a large-size rectangular piezoelectric composite plate with the quasi-periodic PC structure composed of PZT-4 and epoxy is proposed in this *** PC structure can suppress the transverse vibration of the piezoelectric composite plate so that the thickness mode is purer and the thickness vibration amplitude is more ***,the vibration of the model is analyzed theoretically,the electromechanical equivalent circuit diagram of three-dimensional coupled vibration is established,and the resonance frequency equation is *** effects of the length,width,and thickness of the piezoelectric composite plate at the resonant frequency are obtained by the analytical method and the finite element method,the effective electromechanical coupling coefficient is also *** results show that the resonant frequency can be changed regularly and the electromechanical conversion can be improved by adjusting the size of the rectangular piezoelectric *** effect of the volume fraction of the scatterer on the resonant frequency in the thickness direction is studied by the finite element *** band gap in X and Y directions of large-size rectangular piezoelectric plate with quasi-periodic PC structures are *** results show that the theoretical results are in good agreement with the simulation *** the resonance frequency is in the band gap,the decoupling phenomenon occurs,and then the vibration mode in the thickness direction is purer.

关键词： composite materials rectangular piezoelectric plate coupled vibration band gap

DYNAMIC ANALYSIS OF A SPATIAL coupled TIMOSHENKO ROTATING SHAFT WITH LARGE DISPLACEMENTS

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Applied Mathematics and Mechanics(English Edition) 2002年第12期23卷 1413-1420页

作者： ZHU Huai-liang(朱怀亮) Department of Mechanics Shanghai University Shanghai 200436 P R China

The dynamic simulation is presented for an axial moving flexible rotating shafts, which have large rigid motions and small elastic deformation. The effects of the axial inertia, shear deformation, rotating inertia, gyroscopic moment, and dynamic unbalance are considered based on the Timoshenko rotating shaft theory. The equations of motion and boundary conditions are derived by Hamilton principle, and the solution is obtained by using the perturbation approach and assuming mode method. This study confirms that the influence of the axial rigid motion, shear deformation, slenderness ratio and rotating speed on the dynamic behavior of Timoshenko rotating shaft is evident, especially to a high-angular velocity rotor.

关键词： Timoshenko rating shaft dynamic response nonlinear model coupled vibration

A Study on the Influence of Mass Change on vibration Characteristic of ISD Suspension

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A Study on the Influence of Mass Change on Vibration Charact...