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BUCKLING AND POSTBUCKLING ANALYSIS OF ELASTO-PLASTIC FIBER METAL LAMINATES

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Acta Mechanica Solida Sinica 2014年第1期27卷 73-84页

作者： Rengui Bi Yiming Fu Yanping Tian Chao Jiang state key laboratory of advanced design and manufacturing for vehicle body Hunan University College of Mechanical and vehicle Engineering Hunan University School of Mechanical Engineering Hangzhou Dianzi University

The elasto-plastic buckling and postbuckling of fiber metal laminates （FML） are studied in this research. Considering the geometric nonlinearity of the structure and the elasto- plastic deformation of the metal layers, the incremental Von Karman geometric relation of the FML with initial deflection is established. Moreover, an incremental elasto-plastic constitutive relation adopting the mixed hardening rule is introduced to depict the stress-strain relationship of the metal layers. Subsequently, the incremental nonlinear governing equations of the FML subjected to in-plane compressive loads are derived, and the whole problem is solved by the iterative method according to the finite difference method. In numerical examples, the effects of the initial deflection, the loading state, and the geometric parameters on the elasto-plastic buckling and postbuckling of FML are investigated, respectively.

关键词： fiber metal laminates elasto-plastic buckling postbuckling

Middle range wireless power transfer systems with multiple resonators

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Journal of Central South University 2015年第6期22卷 2127-2136页

作者：陈新张桂香 state key laboratory of advanced design and manufacturing for vehicle body (Hunan University) Department of Energy and Electrical Engineering Hunan University of Humanities Science and Technology

The equivalent two-port network model of a middle range wireless power transfer(WPT) system was presented based on strongly coupled multiple resonators. The key parameters of the WPT system include self-inductance, resistance, parasitic capacitance, mutual inductance and S-parameters of coils & resonators were analyzed. The impedance matching method was used to optimize load power and transmission efficiency of the multi-resonator WPT system, and the impedance matching method was realized through adjusting the distances between the coils and resonators. Experiments show that the impedance matching method can effectively improve load power and transmission efficiency for middle range wireless power transfer systems with multiple resonators, at distances up to 3 times the coil radius with efficiency more than 70% and load power also close to 3.5 W.

关键词： wireless power transfer middle range multiple resonators S-parameters two-port network impedance matching

Developing Mechanical Metamaterials Under an Adaptable Topology Optimization design Framework

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Acta Mechanica Solida Sinica 2023年第2期36卷 306-316页

作者： Zhengtong Han Kai Wei Xiaoyang Liu Yuhang Long Jialong Li Xinglin Chen state key laboratory of advanced design and manufacturing for vehicle body Hunan UniversityChangsha 410082China state key laboratory of High Performance Complex manufacturing Central South UniversityChangsha 410083China

Developing mechanical metamaterials through topology optimization attracts high attention in both computational design and engineering ***,most of the studies in the literature are of quite limited applicability and poor ***,this work originally established an adaptable metamaterial topology optimization framework through integrating a commercial finite element analysis(FEA)***,the sensitivity analysis was derived and simplified to avoid the complex extraction of internal FEA information according to the strain-energy-based homogenization method.A series of two-and three-dimensional metamaterials with different properties,i.e.,bulk and shear moduli,negative Poisson’s ratio,were subsequently *** optimized metamaterials were fabricated and experimentally tested based on the additive manufacturing,firmly demonstrating the effectiveness of the developed design *** well-structured design framework can be conveniently extended to the systematic design of metamaterials with various other exclusive performances,fulfilling the urgent need for metamaterial design methods.

关键词： Metamaterial Topology optimization Mechanical properties Tensile experiments

Hashin Failure Theory Based Damage Assessment Methodology of Composite Tidal Turbine Blades and Implications for the Blade design

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China Ocean Engineering 2018年第2期32卷 216-225页

作者： YU Guo-qing REN Yi-ru ZHANG Tian-tian XIAO Wan-shen JIANG Hong-yong state key laboratory of advanced design and manufacturing for vehicle body Hunan University College of Mechanical and vehicle Engineering Hunan University Strategic Development Department China Three Gorges Corporations

A damage assessment methodology based on the Hashin failure theory for glass fiber reinforced polymer(GFRP)composite blade is proposed. The typical failure mechanisms including the fiber tension/compression and matrix tension/compression are considered to describe the damage behaviors. To give the flapwise and edgewise loading along the blade span, the Blade Element Momentum Theory(BEMT) is adopted. In conjunction with the hydrodynamic analysis, the structural analysis of the composite blade is cooperatively performed with the Hashin damage model. The damage characteristics of the composite blade, under normal and extreme operational conditions,are comparatively analyzed. Numerical results demonstrate that the matrix tension damage is the most significant failure mode which occurs in the mid-span of the blade. The blade internal configurations including the box-beam, Ibeam, left-C beam and right-C beam are compared and analyzed. The GFRP and carbon fiber reinforced polymer(CFRP) are considered and combined. Numerical results show that the I-beam is the best structural type. The structural performance of composite tidal turbine blades could be improved by combining the GFRP and CFRP structure considering the damage and cost-effectiveness synthetically.

关键词： composites tidal current turbine blade damage assessment tidal energy Hashin failure theory blade design

Fractional-order visco-plastic constitutive model for uniaxial ratcheting behaviors

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Applied Mathematics and Mechanics(English Edition) 2019年第1期40卷 49-62页

作者： Wenjie ZHAO Shaopu YANG Guilin WEN Xuehong REN state key laboratory of advanced design and manufacturing for vehicle body Hunan University state key laboratory of Mechanical Behavior in Traffic Engineering Structure and System Safety Shijiazhuang Tiedao University

This paper proposes a novel unified visco-plastic constitutive model for uniaxial ratcheting behaviors. The cyclic deformation of the material presents remarkable time-dependence and history memory phenomena. The fractional(fractional-order)derivative is an efficient tool for modeling these phenomena. Therefore, we develop a cyclic fractional-order unified visco-plastic(FVP) constitutive model. Specifically, within the framework of the cyclic elasto-plastic theory, the fractional derivative is used to describe the accumulated plastic strain rate and nonlinear kinematic hardening rule based on the Ohno-Abdel-Karim model. Moreover, a new radial return method for the back stress is developed to describe the unclosed hysteresis loops of the stress-strain *** capacity of the FVP model used to predict the cyclic deformation of the SS304 stainless steel is verified through a comparison with the corresponding experimental data found in the literature(KANG, G. Z., KAN, Q. H., ZHANG, J., and SUN, Y. F. Timedependent ratcheting experiments of SS304 stainless steel. International Journal of Plasticity, 22(5), 858–894(2006)). The FVP model is shown to be successful in predicting the rate-dependent ratcheting behaviors of the SS304 stainless steel.

关键词： cyclic visco-plastic constitutive fractional derivative fractional-order uni-fied visco-plastic(FVP)model rate-dependent ratcheting

Sulfur poisoning mechanism of three way catalytic converter and its grey relational analysis

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Journal of Central South University 2014年第11期21卷 4091-4096页

作者：蔡皓刘亚飞龚金科鄂加强耿玉鹤余立平 state key laboratory of advanced design and manufacturing for vehicle body (Hunan University) GAC Mitsubishi Motor Co. Ltd.

Combining a detailed catalytic surface reaction mechanism with noble metal and promoter elementary reactions, a new three-way catalytic converter(TWC) reaction mechanism is established. Based on the new mechanism, steady condition numerical simulation is carried out, and the change of light-off temperatures and conversion efficiency with various SO2 contents is obtained. By grey relational analysis(GRA), the relational grade between conversion efficiency and SO2 content is obtained. And, the result shows that SO2 content has the most important influence on C3H6 and NOX conversion efficiency. This provides an important reference to the improvement of activity design of TWC, and may provide guidance for the condition design and optimization of TWC.

关键词： sulfur poisoning three-way catalytic converter reaction mechanism numerical simulation grey relational analysis

Screw dislocations interacting with two asymmetrical interfacial cracks emanating from an elliptical hole

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Chinese Physics B 2013年第1期22卷 356-362页

作者：曾鑫方棋洪刘又文 P. H. Wen state key laboratory of advanced design and manufacturing for vehicle body Hunan University College of Mechanical and vehicle Engineering Hunan University School of Engineering and Material Sciences Queen Mary University of London

The interaction between screw dislocations and two asymmetrical interfacial cracks emanating from an elliptic hole under loads at infinity is studied. The closed-form solution is derived for complex potentials. The stress intensity factor and the critical applied stress for the dislocation emission are also calculated. In the limiting cases, well-known results can be obtained from the present solutions. Moreover, new exact solutions for a screw dislocation interacting with some complicated cracks are derived. The results show that the shielding effect increases with the increase in the length of the other cracks and the minor semi axis, but decreases with the increase of dislocation azimuth. The repulsion acting on the dislocation from the other phase and the other crack extend in the horizontal direction, which makes the dislocation emission at the crack tip take place more easily, but the minor semi axis of the elliptical hole extending in the vertical direction makes it more difficult.

关键词： interfacial crack elliptic hole shielding effect dislocation emission

Experimental research on the mechanism of non-monotonic characteristic between curing temperature and mechanical behaviors of Kevlar/epoxy composite

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Science China(Technological Sciences) 2018年第7期61卷 1012-1020页

作者： LIU Li HU DeAn ZHANG YouMin HAN Xu state key laboratory of advanced design and manufacturing for vehicle body Hunan University key laboratory of advanced design and Simulation Technology for Special Equipments Ministry of Education Hunan University School of Mechanical Engineering Hebei University of Technology

An experimental procedure is conducted to investigate the mechanism of the non-monotonic characteristic between curing temperature and mechanical behaviors of the Kevlar/epoxy composite in macro and micro levels. Different specimens are fabricated at four different curing temperatures and tested with ±45° off-axis tensile loading on a universal test machine coupled with digital image correlation(DIC). Moreover, the environmental scanning electron microscope(SEM) was used to obtain the micrographs and reveal their mechanism. The tested results show that the tensile mechanical behaviors are sensitive to the curing temperature and the relationship is non-monotonic. Also, as the temperature increases, the thicknesses of the specimens are significantly enlarged. By analyzing the SEM micrographs of the matrix grooves in the damage zone and DIC strain contours, it is concluded that the non-monotonic relationship is dominated by the properties of the Kevlar/epoxy interfaces and deformation of the distorted fibers.

关键词： Kevlar/epoxy composite mechanical behavior digital image correlation SEM micrograph non-monotonic character-istic distorted fiber

Coating highly lithiophilic Zn on Cu foil for high-performance lithium metal batteries

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Rare Metals 2022年第4期41卷 1255-1264页

作者： Yun-Xiong Song Wei-Yi Lu Yue-Jiao Chen Hao Yang Chen Wu Wei-Feng Wei Li-Bao Chen Xiao-Ping Ouyang state key laboratory of advanced design and manufacturing for vehicle body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China state key laboratory for Powder Metallurgy Central South UniversityChangsha 410083China

Lithium metal batteries(LMBs) are ideal candidates for next-generation high energy density energy storage ***,uncontrollable growth of Li dendrites due to uneven Li plating has restricted the practical application of the Li metal ***,we develop a highly lithiophilic Zn coating on commercial Cu foil as a substrate for Li metal anode to settle above *** find that the lithiophilic nature of Zn can facilitate homogeneous nucleation and deposition of Li on Cu current collector *** addition,the uniform Zn coating can not only decrease the nucleation overpotential but also regulate the electric field *** from the coated Zn layer,the designed anode for half-cell and full-cell tests shows better electrochemical performances compared with the untreated Cu *** work provides a simple and effective way to enable a promising dendrite-free lithium metal anode for large-scale industrial applications.

关键词： Lithiophilic Cu collector surface Coated Zn layer Better electrochemical performances Lithium metal anode