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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1115-1125页

作者： Binghui hu Yu Lei Hang Li Ziyi wang chao Yu guozheng Kang applied mechanics and Structure Safety Key Laboratory of Sichuan province School of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu 610031China

The nonproportional multiaxial ratchetting of cast AZ91 magnesium (Mg) alloy was examined by performing a sequence of axial-torsional cyclic tests controlled by stress with various loading paths at room temperature (rT).The evolutionary characteristics and path dependence of multiaxial ratchetting were *** illustrate that the cast AZ91 Mg alloy exhibits considerable nonproportional additional softening during cyclic loading with multiple nonproportional multiaxial loading paths;multiaxial ratchetting presents strong path dependence,and axial ratchetting strains are larger under nonproportional loading paths than under uniaxial and proportional45°linear loading paths;multiaxial ratchetting becomes increasingly pronounced as the applied stress amplitude and axial mean stress ***,stress-strain curves show a convex and symmetrical shape in axial/torsional *** ratchetting exhibits quasi-shakedown after certain loading *** abundant experimental data obtained in this work can be used to develop a cyclic plasticity model of cast Mg alloys.

关键词： cast magnesium alloy ratchetting multiaxial loading loading path stress level

A non-probabilistic reliability topology optimization method based on aggregation function and matrix multiplication considering buckling response constraints

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applied Mathematics and mechanics(English Edition) 2024年第2期45卷 321-336页

作者： Lei wang Yingge LIU Juxi hu Weimin CHEN Bing HAN Institute of Solid mechanics School of Aeronautic Science and EngineeringBeihang UniversityBeijing 100191China Aircraft and propulsion Laboratory Ningbo Institute of TechnologyBeihang UniversityNingbo 315100Zhejiang ProvinceChina State Key Laboratory of Navigation and Safety Technology Shanghai Ship and Shipping Research InstituteShanghai 200135China National engineering research Center of Ship&Shipping Control System Shanghai Ship and Shipping Research InstituteShanghai 200135China

A non-probabilistic reliability topology optimization method is proposed based on the aggregation function and matrix *** expression of the geometric stiffness matrix is derived,the finite element linear buckling analysis is conducted,and the sensitivity solution of the linear buckling factor is *** a specific problem in linear buckling topology optimization,a Heaviside projection function based on the exponential smooth growth is developed to eliminate the gray *** aggregation function method is used to consider the high-order eigenvalues,so as to obtain continuous sensitivity information and refined structural *** cyclic matrix programming,a fast topology optimization method that can be used to efficiently obtain the unit assembly and sensitivity solution is *** maximize the buckling load,under the constraint of the given buckling load,two types of topological optimization columns are *** variable density method is used to achieve the topology optimization solution along with the moving asymptote optimization *** vertex method and the matching point method are used to carry out an uncertainty propagation analysis,and the non-probability reliability topology optimization method considering buckling responses is developed based on the transformation of non-probability reliability indices based on the characteristic ***,the differences in the structural topology optimization under different reliability degrees are illustrated by examples.

关键词： buckling topology optimization aggregation function uncertainty propagation analysis non-probabilistic reliability

A human-sensitive frequency band vibration isolator for heavy-duty truck seats

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applied Mathematics and mechanics(English Edition) 2024年第10期45卷 1733-1748页

作者： Qingqing LIU Shenlong wang Ge YAN hu DING Haihua wang Qiang SHI Xiaohong DING huijie YU school of Mechanical engineering University of Shanghai for Science and TechnologyShanghai 200093China State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China shanghai Key Laboratory of mechanics in Energy engineering Shanghai Frontier Science Center of MechnoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China State Key Laboratory of Advanced Design and Manufacturing for Vehicle body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China Yanfeng Adient Seating Co. Ltd.Shanghai 201315China College of Mechanical and Electrical engineering Jiaxing Nanhu UniversityJiaxing 314001Zhejiang ProvinceChina

In this study,a human-sensitive frequency band vibration isolator(HFBVI)with quasi-zero stiffness(QZS)characteristics for heavy-duty truck seats is designed to improve the comfort of heavy-duty truck drivers on uneven ***,the analytical expressions for the force and displacement of the HFBVI are derived with the Lagrange equation and d'Alembert's principle,and are validated through the prototype restoring force ***,the harmonic balance method(HBM)is used to obtain the dynamic responses under harmonic excitation,and further the influence of pre-stretching on the dynamic characteristics and transmissibility is ***,the experimental prototype of the HFBVI is fabricated,and vibration experiments are conducted under harmonic excitation to verify the vibration isolation performance(VIp)of the proposed vibration *** experimental results indicate that the HFBVI can effectively suppress the frequency band(4-8 Hz)to which the human body is sensitive to vertical *** addition,under real random road spectrum excitation,the HFBVI can achieve low-frequency vibration isolation close to 2 Hz,providing new prospects for ensuring the health of heavy-duty truck drivers.

关键词： human-sensitive frequency band quasi-zero stiffness(QZS) heavy-duty truck seat real random road spectrum low-frequency vibration isolation

ANTI-pLANE SHEAr CrACK IN A FUNCTIONALLY GrADIENT pIEZOELECTrIC LAYEr boNDED TO DISSIMILAr HALF SpACES

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ANTI-PLANE SHEAR CRACK IN A FUNCTIONALLY GRADIENT PIEZOELECT...

Dynamics of cantilever plates and its hybrid vibration control

中国力学学会学术大会'2005

作者： hu Keqiang Zhong Zheng Jin bo (Department of Building and Structural engineering, College of Civil engineering, tongji university, shanghai 200092, china) (Key Laboratory of Solid mechanics of MOE, school of aerospace engineeringand applied mechanics, tongji university, shanghai, 200092,. china)

piezoelectric sensors and actuators have attracted attention in the active noise and vibration control area. In particular, control of laminated structures including piezoelectric devices has been extensively studied by many researchers. In some practical structures, one major concern has been the mechanical failure of the piezoelectric ceramic layers. Usually the discrepancies in mechanical and piezoelectric properties between the component materials cause the cracking of the interface and therefore influence the strength of the whole structure. To meet the demand of advanced piezoelectric materials in lifetime and reliability and with the help of the development

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Acta Mechanica Sinica 2013年第5期29卷 738-748页

作者： bo ni chao hu school of aerospace engineering and applied mechanics Tongji University shanghai Institute of Spaceflight Fundamental Technology College of Civil Science and engineering Yangzhou University

Applying Lagrange-Germain＇s theory of elas- tic thin plates and Hamiltonian formulation, the dynamics of cantilever plates and the problem of its vibration control are studied, and a general solution is finally given. Based on Hamiltonian and Lagrangian density function, we can obtain the flexural wave equation of the plate and the relationship between the transverse and the longitudinal eigenvalues. Based on eigenfunction expansion, dispersion equations of propagation mode of cantilever plates are deduced. By satisfying the boundary conditions of cantilever plates, the natural frequencies of the cantilever plate structure can be given. Then, analytic solution of the problem in plate structure is obtained. An hybrid wave/mode control approach, which is based on both independent modal space control and wave control methods, is described and adopted to analyze the active vibration control of cantilever plates. The low-order （controlled by modal control） and the high-order （controlled by wave control） frequency response of plates are both improved. The control spillover is avoided and the robustness of the system is also improved. Finally, simulation results are analyzed and discussed.

关键词： Cantilever plate Hamiltonian formulism - Dis- persion equations Modal control Elastic wave control - Hybrid control

1:3 resonant Double Hopf Bifurcation on Two Coupled Limit Cycle Oscillators with Delay Coupling

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1:3 Resonant Double Hopf Bifurcation on Two Coupled Limit Cy...

第十三届全国非线性振动暨第十届全国非线性动力学和运动稳定性学术会议

作者： wang Wan-yong1,XU Jian1(1.school of aerospace engineering and applied mechanics,tongji university,shanghai 200092,china)

The dynamical behaviour of two coupled limit cycle oscillators around a 1:3 resonant double Hopf bifurcation point is *** parameters including time delay are chosen as the bifurcation parameters,then the method of multiple scales is used to obtain bifurcation *** analyzing the bifurcation equations,the dynamical behaviour arising from the bifurcation is classified qualitatively in two-parameter cross-section by fixing one of the three bifurcation *** results show rich dynamical phenomena including the amplitude death,periodic solution and quasiperiodic *** particular,by varying time delay,the exchange of energy between two oscillators is *** simulation results are also given to support the theoretical predictions.

关键词： the method of multiple scales resonance double Hopf bifurcation time delay

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轴对称柱坐标系中的Youngs算法

同济大学学报（自然科学版） 2004年第7期32卷 916-919页

作者：胡影影朱克勤席葆树同济大学航空航天与力学学院上海200092 清华大学工程力学系北京100084

为提高包含有交界面的轴对称流动问题的求解精度 ,将直角系中的Youngs算法公式推广到轴对称柱系中应用 .根据流体体积分数的定义 ,在直角系Youngs算法的基础上 ,通过引入修正系数 ,可以方便地实现Youngs算法在轴对称柱坐标系中的应用 .... 详细信息

为提高包含有交界面的轴对称流动问题的求解精度 ,将直角系中的Youngs算法公式推广到轴对称柱系中应用 .根据流体体积分数的定义 ,在直角系Youngs算法的基础上 ,通过引入修正系数 ,可以方便地实现Youngs算法在轴对称柱坐标系中的应用 .最后在轴对称情况下 ,数值模拟了空泡在理想流场中的溃灭过程 ,通过比较空泡半径理论解和由Youngs算法得到的数值解 ,检验Youngs算法在轴对称情况下的应用 .

关键词：轴对称柱坐标系 Youngs算法流体体积分数交界面

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时滞对于参数激励系统周期运动的影响

力学季刊 2004年第3期25卷 367-374页

作者：戴护军徐鉴固体力学教育部重点实验室

本文以结构物承受周期激励地震波和具有时滞的弹性地基为背景,研究时滞对于结构物振动响应的影响规律。问题的数学模型是一个非线性参数激励时滞系统,采用中心流形和平均法得到Hopf分岔方程,研究结果表明时滞量对结构物的地震响应有重... 详细信息

本文以结构物承受周期激励地震波和具有时滞的弹性地基为背景,研究时滞对于结构物振动响应的影响规律。问题的数学模型是一个非线性参数激励时滞系统,采用中心流形和平均法得到Hopf分岔方程,研究结果表明时滞量对结构物的地震响应有重要影响,它可使响应振幅增大,意味着结构物遭破坏的危险性增大,同时,结果也表明可以通过阻尼控制器克服时滞引起的危险性。最后,对于不同的时滞量,比较理论分析与数值模拟结果基本吻合,说明了本文结果的可靠性。

关键词：参数激励系统时滞微分方程 Hopf分岔振动控制

Ultrathin polyimide-based composites with efficient low-reflectivity electromagnetic shielding and infrared stealth performance

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Nano research 2024年第7期17卷 6700-6712页

作者： Xu Zhao Xinwei Tang Yunlong Qiao Shuangshuang Li Zihang Zhang Yezi Lu Mingyang Zhu Zaiyin hu Lijuan Long Zicheng wang Tianxi Liu The Key Laboratory of Synthetic and Biological Colloids Ministry of EducationSchool of Chemical and Material EngineeringInternational Joint Research Laboratory for Nano Energy CompositesJiangnan UniversityWuxi 214122China Guizhou aerospace Wujiang Electro-mechanical Equipment Co. Ltd.No.20-5Dalian Road Aerospace Industrial ParkHuichuan DistrictZunyi 563000China school of Materials and Architectural engineering Guizhou Normal UniversityGuiyang 550025China

researching and manufacturing materials that possess both electromagnetic interference(EMI)shielding and infrared stealth capabilities is of great ***,an ultrathin polyimide-based nonwoven fabric with low-reflection EMI shielding/infrared stealth performance is successfully fabricated by in-situ loading of Fe_(3)O_(4)/Ag nanoparticles on the surface of polyimide(pI)fiber(pFA),and followed by bonding with a commercial Cu/ni *** synergistic assembly of pFA and Cu/ni promotes the rational construction of hierarchical impedance matching,inducing electromagnetic waves(EMW)to enter the composite and be dissipated as much as ***,the existence of Cu/ni mesh on back of pFA facilitates the formation of electromagnetic resonance and destructive interference of EMW reflected from composite,leading to a lowerreflectivity(0.26)EMI shielding performance of 58 dB within 24–40 GHz at a thinner thickness(430μm).More importantly,the fluffy pFA nonwoven fabric and metal Cu/ni mesh endow composite with good thermal insulation and low infrared emissivity,resulting in excellent infrared stealth performance in various *** a result,such excellent compatibility makes it possible to become a promising defense material to be applied in military tent for preventing electromagnetic and infrared radiation.

关键词： polyimide electromagnetic interference shielding low reflection infrared stealth