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Acta Mechanica Sinica 2008年第6期24卷 709-720页

作者： F.H.Zhu .M.Fu College of Mechanics and Aerospace Hunan University410082 ChangshaChina

By considering the effect of interfacial damage and using the variation principle, three-dimensional nonlinear dynamic governing equations of the laminated plates with interfacial damage are derived based on the general sixdegrees-of-freedom plate theory towards the accurate stress analysis. The solutions of interlaminar stress and nonlinear dynamic response for a simply supported laminated plate with interfacial damage are obtained by using the finite difference method, and the results are validated by comparison with the solution of nonlinear finite element method. In numerical calculations, the effects of interfacial damage on the stress in the interface and the nonlinear dynamic response of laminated plates are discussed.

关键词： Laminated plates Geometric nonlinearity Accurate stress analysis Interfacial damage Interlaminar stress nonlinear dynamic response

ANALYSIS OF nonlinear dynamic response FOR VISCOELASTIC COMPOSITE PLATE WITH TRANSVERSE MATRIX CRACKS

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Acta Mechanica Solida Sinica 2004年第3期17卷 230-238页

作者： FuYiming LiPing＇en ZhengYufang DepartmentofEngineeringMechanics HunanUniversityChangsha410082China

Based on the Schapery three-dimensional viscoelastic constitutive relationship with growing damage, a damage model with transverse matrix cracks for the unidirectional ?bre rein- forced viscoelastic composite plates is developed. By using Karman theory, the nonlinear dynamic governing equations of the viscoelastic composite plates under transverse periodic loading are es- tablished. By applying the ?nite di?erence method in spatial domain and the Newton-Newmark method in time domain, and using the iterative procedure, the integral-partial di?erential gov- erning equations are solved. Some examples are given and the results are compared with available data.

关键词： viscoelastic composite plate transverse matrix cracks damage evolution equation nonlinear dynamic response

nonlinear dynamic analysis of cantilevered piezoelectric energy harvesters under simultaneous parametric and external excitations

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Acta Mechanica Sinica 2018年第3期34卷 561-577页

作者： Fei Fang Guanghui Xia Jianguo Wang School of Civil and Hydraulic Engineering Hefei University of Technology

The nonlinear dynamics of cantilevered piezoelectric beams is investigated under simultaneous parametric and external excitations. The beam is composed of a substrate and two piezoelectric layers and assumed as an Euler-Bernoulli model with inextensible deformation. A nonlinear distributed parameter model of cantilevered piezoelectric energy harvesters is proposed using the generalized Hamilton＇s principle. The proposed model includes geometric and inertia nonlinearity, but neglects the material nonlinearity. Using the Galerkin decomposition method and harmonic balance method, analytical expressions of the frequency-response curves are presented when the first bending mode of the beam plays a dominant role. Using these expressions, we investigate the effects of the damping, load resistance, electromechanical coupling, and excitation amplitude on the frequency-response curves. We also study the difference between the nonlinear lumped-parameter and distributed- parameter model for predicting the performance of the energy harvesting system. Only in the case of parametric excitation, we demonstrate that the energy harvesting system has an initiation excitation threshold below which no energy can be harvested. We also illustrate that the damping and load resistance affect the initiation excitation threshold.

关键词： Parametric and external excitations nonlinear distributed parameter model nonlinear dynamic response Energy harvesting Harmonic balance method

Investigation of Induced Unbalance Magnitude on dynamic Characteristics of High-speed Turbocharger with Floating Ring Bearings

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Chinese Journal of Mechanical Engineering 2018年第5期31卷 99-109页

作者： Guang-Fu Bin Yuan Huang Shuai-Ping Guo Xue-Jun Li Gang Wang Health Maintenance for Mechanical Equipment Key Lab of Hunan Province Hunan University of Science and Technology Xiangtan 411201 China Department of Mechanical and Aerospace Engineering The University of Alabama in Huntsville AL 35899 USA

Due to operational wear and uneven carbon absorption in compressor and turbine wheels, the unbalance(me) vibration is induced and could lead to sub?synchronous vibration accidents for high?speed turbocharger(TC). There are very few research works that focus on the magnitude e ects on such induced unbalance vibration. In this paper, a finite element model(FEM) is developed to characterize a realistic automotive TC rotor with floating ring bearings(FRBs). The nonlinear dynamic responses of the TC rotor system with di erent levels of induced unbalance magni?tude in compressor and turbine wheels are calculated. From the results of waterfall and response spectral intensity plots, the bifurcation and instability phenomena depend on unbalance magnitude during the startup of TC. The sub?synchronous component 0.12× caused rotor unstable is the dominant frequency for small induced unbalance. The nonlinear e ects of induced unbalance in the turbine wheel is obvious stronger than the compressor wheel. As the unbalance magnitude increases from 0.05 gbration 1·mm to 0.2 g·mm, the vibration component changes from mainly 0.12× to synchronous vi×. When unbalance increases continuously, the rotor vibration response amplitude is rapidly growing and the 1× caused by the large unbalance excitation becomes the dominant frequency. A suitable un?balance magnitude of turbine wheel and compressor wheel for the high?speed TC rotor with FRBs is proposed: the value of induced un?balance magnitude should be kept around 0.2 g·mm.

关键词： High?speed TC with FRBs Induced unbalance magnitude nonlinear dynamic response Sub?synchronous vibration Stability

Time-Domain nonlinear Wave-Current Interaction with A Steep Wave Riser Considering Internal Flow Effect

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China Ocean Engineering 2021年第3期35卷 410-421页

作者： TANG Lian-yang CHENG Yong JI Chun-yan School of naval architecture and ocean engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Nippon Kaiji Kyokai(China)Co. LtdShanghai 200336China

The nonlinear dynamic response induced by the wave-current interaction on a deepwater steep wave riser(SWR)is numerically investigated based on a three-dimensional(3 D)time-domain finite element method(FEM).The governing equation considering internal flow is established in the global coordinate *** whole SWR consists of three segments:the decline segment,buoyancy segment and hang-off segment,in which the buoyancy segment is wrapped by several buoyancy modules in the middle section,leading to the arch bend and sag bend.A Newmark-β iterative scheme is adopted for the accurate analysis to solve the governing equation and update the dynamic response at each time *** proposed method is verified through the published results for the dynamic response of steel catenary riser(SCR)and static configuration of steel lazy wave riser(SLWR).Simulations are executed to study the influence of wave height,current velocity/direction,internal flow density/velocity and top-end pressure on the tension,configuration and bending moment of the *** results indicate that the influence of the current on the configuration and mechanical behavior of the SWR is greater than that of the wave,especially in the middle *** increasing current velocity,the suspending height of the middle section drops,meanwhile,its bending moment decreases accordingly,but the tension increases *** a fixed external load,the increasing internal flow density induces the amplification of the tension at the hang-off segment and the mitigation at the decline segment,while the opposite trend occurs at the bending moment.

关键词： steep wave riser(SWR) nonlinear dynamic response wave-current interaction time-domain finite element method(FEM)

Experimental and Numerical Investigations of the dynamic response of Ring-Stiffened Cylinder Subjected to Underwater Explosion

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Journal of Beijing Institute of Technology 2004年第3期13卷 346-350页

作者：朱锡张振华冯刚李玉节刘建湖何斌 Department of Naval Architecture and Ocean Engineering Naval University of Engineering Wuhan Hubei430033 China China Ship Scientific Research Center Wuxi Jiangsu214082 China

Experimental and numerical investigations were carried out on the free-free end ring-stiffened cylinder subjected to underwater explosion loading. Numerical analysis was carried out by using the *** finite element code and the results were compared with experiment results. General coupling was used to simulate the interaction between fluid and structure. The strain rate effect, geometric nonlinearity and initial abnormity in shape were considered. The effective plastic stress and the strain of shell between ribs on different locations were compared and damage mechanism were analyzed..

关键词： underwater explosion ring-stiffened cylinder nonlinear dynamic response

dynamic behavior of laterally loaded caisson foundations based on different cushion types: an experimental and theoretical study

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2020年第7期21卷 565-579页

作者： Wen-bo TU Mao-song HUANG Xiao-qiang GU School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang 330013China Department of Geotechnical Engineering Tongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China

Bridge foundations located in deep water are usually subjected to horizontal dynamic loads and moments which may be caused by the wind, waves, earthquake, and the possibility of boat crashing or vehicle braking. Caisson foundations based on gravel or sand cushions are a new type of deep-water foundation for bridges, suitable for meizoseismal areas. In this paper, harmonic horizontal excitation tests for the study of the lateral dynamic response of caisson foundations based on cushion layers are described. Different lateral loads and two different cushion types are considered. The results show that the lateral dynamic responses of caisson foundations based on sand and gravel cushions both show strong nonlinear characteristics, and the resonant frequency of the foundation decreases with the increase of the excitation force. The dynamic displacement of a foundation based on a sand cushion is far less than that based on a gravel cushion, and the rate of decrease of the resonant frequency of a foundation based on a gravel cushion is faster than that of a foundation based on a sand cushion under the same conditions. Under dynamic loading the gravel cushion can more effectively dissipate vibration energy and isolate the vibration, than the sand cushion can. A simplified nonlinear analysis method is proposed to simulate the lateral dynamic response of caisson foundations, and the predicted response shows a reasonable match with the results observed in laboratory tests. Scaling laws have also been applied in this small-scale vibration model test to predict the dynamic behavior of the prototype foundation.

关键词： nonlinear dynamic response Caisson foundation Harmonic vibration test Gravel cushion Sand cushion