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FEM Simulation of bending Formability for Laminate Steel/Resin/Steel Lightweight Composite Sheet

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Journal of Materials Science & Technology 2003年第4期19卷 324-326页

作者： GuanchengLI YonglinKANG Dept.ofBasicScienceSubjects HuaihaiInstituteLianyungang222000China SchoolofMaterialsScienceandEngineering UniversityofScience&TechnologyGeijingBeijing100083China

The ANSYS simulation software was used to analyze the bending formability of laminate steel/resin/steel lightweight composite sheet. The skin steel at external side produces relative slipping-off change during the bending due to its composite structure. The internal stress strain states, materials effect tools parameters and intermediate layer resin of lightweight sheet on slipping-off change were analyzed. The spring back and shear stress state after bending have also been discussed.

关键词： Resin Laminate steel sheet bending Formability Numerical simulation

bending Hysteresis of Twill Woven Fabrics in Various Directions

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Journal of China Textile University(English Edition) 1999年第3期16卷 37-41页

作者：卢咏敏胡金莲卢明德 The Hong Kong Polytechnic Univ Hongkong Hong Kong

This paper investigates the bending hysteresis of twill woven fabrics in various directions. In this research, existing models for the prediction of bending rigidity of woven fabrics are applied to bending hysteresis. Wide range of cotton twill woven fabrics is examined by comparing the theoretical data and experimental results. The results of this paper indicated that Peirce’s, Shinohara et al’s and Cooper’s models can be applied to the prediction of bending hysteresis of twill woven fabrics. Besides, the results also show that ratio V, introduced by Cooper, of a cotton twill fabric is found to have the range between 0.8 and 1.4. The general shape of the polar diagram of bending hysteresis along the weft direction is spreading outwards with the increase in ratio V from the range 0.8 to 1. However, the general shape of bending hysteresis will collapse around the weft direction when ratio V is increased from 1 and 1.4.

关键词： bending hysteresis polar diagram ratio V.

The analysis of the bending stiffness and intensity of cylindrical tubes

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Science China(Technological Sciences) 2007年第3期50卷 268-278页

作者： SONG YuQuan GUAN ZhiPing NIE YuQin GUAN XiaoFang Superplastic and Plastic Research Institute Jilin UniversityChangchun 130025China Department of Engineering Mechanics Institute of Mechanical Science and EngineeringJilin UniversityChangchun 130025China

Based on the mechanics of material,the bending stiffness and intensity of cylin-drical bar and tube are analyzed. By comparing the cylindrical tube whose ratio of outside diameter to internal diameter is 0.7 with the cylindrical bar,it is concluded that when both of them have the same mass,the section stiffness of the cylindrical tube is three times that of the cylindrical bar;when both of them have the same external diameter,the mass of the cylindrical tube is only 1/2 that of the cylindrical bar,but the section stiffness of the cylindrical tube is 3/4 that of the cylindrical bar. By virtue of the elemental elastic-plastic theory,the yield stress of the liquid-filled cylindrical tube is investigated. Due to the incompressibility of liquid and the strain hardening effect of material,the yield stress of the liquid-filled tube is enlarged compared with the hollow tube,thus raising its bending intensity. Under the dy-namic load,compared with the hollow tube,the impact resistance of the liquid-filled tube is also raised due to elastic recovery. Because the hydraulic pressures per-pendicular to the inner surface are identical everywhere,the local stress concen-tration resulting from the ovalisation of the tube would be decreased,and the re-sistance to buckling would be improved.

关键词： bending of cylindrical tube liquid filled stiffness intensity

Microwave Response of Bi2Sr2CaCu2O8＋δ Surface Intrinsic Josephson Junctions with bending Pancake Vortices

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Chinese Physics Letters 2007年第6期24卷 1709-1712页

作者：魏彦锋赵士平朱晓波陈赓华任育峰于洪伟杨乾声 Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100080

We study the microwave response of surface intrinsic Josephson junctions on Bi2Sr2 CaCu2O8＋δ, in which bending pancake vortex lines are introduced in a controllable way. It is found that the bending vortices can greatly influence the response. In some cases, typical Shapiro steps that lie far above the quasiparticle branch are observed, with the step interval satisfying the Josephson relation and their amplitude versus the square root of microwave power following the Bessel function behaviour. In the other cases, current steps that lie on the quasiparticle branch are observed, but only one or two steps appear at the same time under the variation of the microwave power.

关键词： Microwave Surface bending

Boundary conditions for the bending of a piezoelectric beam

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Science China(Physics,Mechanics & Astronomy) 2008年第7期51卷 847-856页

作者： GAO Yang1, XU SiPeng2 & ZHAO BaoSheng3 1 College of Science, China Agricultural University, Beijing 100083, China 2 College of Engineering, Ocean University of China, Qingdao 266071, China 3 School of Mechanical Engineering, University of Science and Technology Liaoning, Anshan 114044, China College of Science China Agricultural University Beijing China College of Engineering Ocean University of China Qingdao China School of Mechanical Engineering University of Science and Technology Liaoning Anshan China

For beam bending in transversely isotropic piezoelectric media, the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate stress and mixed boundary conditions accurate to all orders for the beam of general edge geometry and loadings. By generalizing the method developed by Gregory and Wan, a set of necessary conditions on the edge-data for the existence of a rapidly decaying solution is established. The prescribed edge-data of the beam must satisfy these conditions in order that they could generate a decaying state within the beam. When stress and mixed conditions are imposed on the beam edge, these decaying state conditions for the case of bending deformation of piezoelectric beam are derived explicitly. They are then used for the correct formulation of boundary conditions for the beam theory solution (or the interior solution). Besides, an analytical solution of elastic beam is formulated to verify validity of our boundary conditions. For the stress data, our boundary conditions coincide with those obtained in conventional forms of beam theories. More importantly, the appropriate boundary conditions with two sets of mixed edge-data are obtained for the first time.

关键词： boundary conditions beam bending piezoelectric media decaying states regular states

A wake bending unsteady dynamic inflow model of tiltrotor in conversion flight of tiltrotor aircraft

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Science China(Technological Sciences) 2009年第11期52卷 3188-3197页

作者： YUE HaiLong XIA PinQi Laboratory of Rotorcraft Aeromechanics Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The aerodynamics, dynamic responses and aeroelasticity of tiltrotor aircraft in the tilting of rotor i.e. in conversion flight are extraordinarily complicated. The traditional quasi-steady assumption model can not reflect the unsteady aerodynamic problems in the tilting of rotor. The CFD method based on the vortex theory can get better results, but it consumes a lot of computing resources. In this paper, a wake bending dynamic inflow model of tilting rotor was established firstly based on the Peters-He dynamic inflow model used in helicopter. Then combining with the ONERA unsteady aerodynamic model, a wake bending unsteady dynamic inflow model of tilting rotor in conversion flight of tiltrotor aircraft was established. The wake bending unsteady dynamic inflow model of tilting rotor was verified by using the experimental data of an isolated rotor model in large angle pitching up maneuver and was used to calculate the dynamic responses of tilting rotor in conversion flight of a tiltrotor aircraft model. The calculated results were analyzed to be physically reasonable.

关键词： tiltrotor dynamic inflow wake bending unsteady aerodynamics

Intra-trench variations in flexural bending of the subducting Pacific Plate along the Tonga-Kermadec Trench

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Acta Oceanologica Sinica 2019年第11期38卷 81-90页

作者： Fan Zhang Jian Lin Zhiyuan Zhou Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Department of Geology and Geophysics Woods Hole Oceanographic InstitutionWoods HoleMA 02543USA Innovation Academy of South China Sea Ecology and Environmental Engineering Chinese Academy of SciencesGuangzhou 510301China

We conducted a detailed analysis of along-trench variations in the flexural bending of the subducting Pacific Plate at the Tonga-Kermadec *** were conducted to obtain best-fitting solutions of trench-axis loadings and variations in the effective elastic plate thickness for the analyzed flexural bending *** of the analyses revealed significant along-trench variations in plate flexural bending:the trench relief(W0)of 1.9 to 5.1 km;trench-axis vertical loading(V0)of-0.5×10^12 to 2.2×10^12 N/m;axial bending moment(M0)of 0.1×10^17 to 2.2×10^17 N;effective elastic plate thickness seaward of the outer-rise region(Te^M)of 20 to 65 km,trench-ward of the outer-rise(Te^M)of 11 to 33 km,and the transition distance(Xr)of 20 to 95 *** Horizon Deep,the second greatest trench depth in the world,has the greatest trench relief(W0 of 5.1km)and trench-axis loading(V0 of 2.2×10^12N/m);these values are only slightly smaller than that of the Challenger Deep(W0 of 5.7km and V0 of 2.9×10^12N/m)and similar to that of the Sirena Deep(W0 of 5.2 km and V0 of 2.0×10^12 N/m)of the Mariana Trench,suggesting that these deeps are linked to great flexural bending of the subducting *** using three independent methods,i.e.,the/inversion,the flexural curvature/yield strength envelope analysis,and the elasto-plastic bending model with normal faults,all yielded similar average Te reduction of 28%-36% and average Te reduction area S△Te of 1195-1402 km^2 near the trench *** calculated brittle yield zone depth from the flexural curvature/yield strength envelope analysis is also consistent with the distribution of the observed normal faulting *** of the Manila,Philippine,Tonga-Kermadec,Japan,and Mariana Trenches revealed that the average values Te^M of Te^M and both in general increase with the subducting plate age.

关键词： Tonga-Kermadec Trench horizon deep axial vertical force axial bending moment effective elastic thickness flexural curvature analysis

Effects of bending on heat transfer performance of axial micro-grooved heat pipe

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Journal of Central South University 2011年第2期18卷 580-586页

作者：蒋乐伦汤勇潘敏强 School of Mechanical and Automotive Engineering South China University of Technology

Heat pipe is always bent in the typical application of electronic heat dissipation at high heat flux,which greatly affects its heat transfer performance. The capillary limit of heat transport in the bent micro-grooved heat pipes was analyzed in the vapor pressure drop,the liquid pressure drop and the interaction of the vapor with wick fluid. The bent heat pipes were fabricated and tested from the bending angle,the bending position and the bending radius. The results show that temperature difference and thermal resistance increase while the heat transfer capacity of the heat pipe decreases,with the increase of the bending angles and the bending position closer to the vapor section. However,the effects of bending radius can be ignored. The result agrees well with the predicted equations.

关键词： electronics cooling system axial micro-grooved heat pipe bending heat transfer performance

An analytic solution to asymmetrical bending problem of diaphragm coupling

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Applied Mathematics and Mechanics(English Edition) 2008年第12期29卷 1643-1649页

作者：朱可柯朱如鹏 College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics

Because rigidity of either hub or rim of diaphragm coupling is much greater than that of the disk, and asymmetrical bending is under the condition of high speed revolution, an assumption is made that each circle in the middle plane before deforma- tion keeps its radius unchanged after deformation, but the plane on which the circle lies has a varying deflecting angle. Based on this assumption, and according to the principle of energy variation, the corresponding Euler＇s equation can be obtained, which has the primary integral. By neglecting some subsidiary factors, an analytic solution is obtained. Applying these formulas to a hyperbolic model of diaphragm, the results show that the octahedral shear stress varies less along either radial or thickness direction, but fluctuates greatly and periodically along circumferential direction. Thus asymmetrical bending significantly affects the material＇s fatigue.

关键词： diaphragm coupling bending stress deformation