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SOME APPLICATIONS OF THE SINGULAR PERTURBATION METHOD TO THE bending PROBLEMS OF THIN PLATES AND SHELLS

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Applied Mathematics and Mechanics(English Edition) 1984年第4期5卷 1449-1457页

作者：周焕文 Wuhan University Wuhan China

This paper presents a review which tackles some nonlinear bending problems of plates and shells in a unified way by means of the technique of undetermined small parameters.

关键词： unified iterative shells bending terat singular coordinates restore salient distr

Distributed curvature sensing based on a bending loss-resistant ring-core fiber

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Photonics Research 2020年第2期8卷 165-174页

作者： LI SHEN HAO WU CAN ZHAO LEI SHEN RUI ZHANG WEIJUN TONG SONGNIAN FU MING TANG Wuhan National Laboratory for Optoelectronics(WNLO)&National Engineering Laboratory for Next Generation Internet Access System School of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Optical Fiber and Cable Manufacture Technology Yangtze Optical Fiber and Cable Joint Stock Limited Company(YOFC)R&D CenterWuhan 430073China

A theoretical and experimental study on curvature sensing using a Brillouin optical time-domain analyzer based on the ring-core fiber(RCF)is *** Brillouin gain spectrum of the RCF is investigated,and the Brillouin frequency shift(BFS)dependence on temperature and strain is *** theoretically analyze the fiber bending-induced BFS and peak Brillouin gain variation for the RCF through a numerical simulation method,and the RCF is revealed to have a high curvature *** curvature sensing is successfully demonstrated,with the bending radius ranging from 0.5 to 1.5 cm,corresponding to a BFS variation from 32.90 to7.81 *** RCF takes advantage of great bending loss resistance,and the maximum macrobending loss at the extreme bending radius of 0.5 cm is less than 0.01 d B/***,the peak Brillouin gain of the RCF is discovered to vary significantly in response to fiber bending,which is expected to be another parameter for distributed curvature *** results imply that the RCF is a promising candidate for highly sensitive distributed curvature measurement,especially in sharp bending circumstances.

关键词： fiber bending curvature

Accounting for speckle-scale beam bending in classical ray tracing schemes for propagating realistic pulses in indirect drive ignition conditions

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Matter and Radiation at Extremes 2023年第2期8卷 33-46页

作者： C.Ruyer P.Loiseau G.Riazuelo R.Riquier A.Debayle P.E.Masson-Laborde O.Morice CEA DAMDIFF-91297 ArpajonFrance CEA LMCEUniversitéParis-Saclay91680 Bruyères-le-ChâtelFrance

We propose a semi-analytical modeling of smoothed laser beam deviation induced by plasma *** on a Gaussian description of speckles,the model includes spatial,temporal,and polarization smoothing techniques,through fits coming from hydrodynamic simulations with a paraxial description of electromagnetic *** beam bending model is then incorporated into a ray tracing algorithm and carefully *** applied as a post-process to the propagation of the inner cone in a full-scale simulation of a National Ignition Facility(NIF)experiment,the beam bending along the path of the laser affects the refraction conditions inside the hohlraum and the energy deposition,and could explain some anomalous refraction measurements,namely,the so-called glint observed in some NIF experiments.

关键词： polarization beam bending

INFLUENCE　OF　CHEMICAL　COMPOSITION　ON　SURFACE　BAND　bending　AS　OBSERVED　THROUGH　SURFACE　PHOTOVOLTAGE　SPECTRA￥

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Chinese Chemical Letters 1994年第4期5卷 333-334页

作者： Jian Feng YU Yan Zhi REN De Jun WANG Tong Hao WU Yi CUI (Department of Chemistry, Jilin University, Changchun 130023)

Measurement of the Surface Photovoltage Spectra(SPS) of Mo/Bi series catalysts BixPMo12Oy(x= 2～ 9, y= 43～ 64) showed that with the increase of Bi/P molar ratio, SPS exhibits some changes characteristic of modulated surface band bendings. The phenomena were explained in terms of the basic capacity of vacancies in the scheelite-type structure of the catalysts.

关键词： AS OBSERVED THROUGH BAND bending

Interfacial toughness evaluation of thermal barrier coatings by bending test

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Theoretical & Applied Mechanics Letters 2018年第1期8卷 3-6页

作者： Qi Zhu Wei He Lei Chen Jianguo Zhu Wenfeng Hao Department of Mechanics and Science Engineering Jiangsu University AML Department of Engineering MechanicsTsinghua University

Determining the interfacial properties of thermal barrier coatings(TBCs) is imperative for their durability evaluation and further improvements. A ceramic coating(topcoat) and a NiCoCrALY bondcoat were atmospheric-plasma-sprayed(APS) on a stainless steel substrate. A modified three-point bending test was adopted to initiate and propagate the topcoat/bondcoat(TC/BC)interfacial crack. After a complete delamination, the fracture surfaces were examined by an optical microscope, which shows that the cracking plane was merely on the TC/BC interface. Based on the experimental results of load–displacement and crack length–displacement,the strain energy release rate G for crack propagation was calculated, and the averaged magnitude was 77.1 J/m^*** results have indicated that the method can be used for the evaluation of interfacial fracture toughness in thermal barrier coatings and other multi-layer structures.

关键词： Thermal barrier coatings Three-point bending Interfacial fracture toughness

Forming Characteristics of Al-alloy Large-diameter Thin-walled Tubes in NC-bending Under Axial Compressive Loads

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Chinese Journal of Aeronautics 2010年第4期23卷 461-469页

作者：闫晶杨合詹梅李恒西北工业大学材料学院凝固技术国家重点实验室

Tube thinning control without wrinkling occurring is a key problem urgently to be solved for improving the forming qualities in numerical control （NC） bending processes of large-diameter Al-alloy thin-walled tubes （AATTs）. It may be a way solving this problem to exert axial compression loads （ACL） on the tube end in the bending. Thus, this article establishes a three-dimensional （3D） elastic-plastic explicit finite element （FE） model for the bending under ACL and has its reliability verified. Through a multi-index orthogonal experiment design, a combination of process parameters, each expressed by a proper range, for this FE model is derived to overcome the compression instability on tube ends. By combining the FE model with a wrinkling energy prediction model, an in-depth study is conducted on the forming characteristics of large-diameter AATTs with small bending radii and it can be concluded that （1） The larger the tube diameters and the smaller the bending radii, the larger the induced tangent tension stress zones on tube intrados, by which the tube maximum tangent compression stress zones will be partitioned in the bending processes; thus, the smaller the ACL roles in decreasing thinning degrees and the larger the compression instability possibilities on tube ends. （2） The tube wrinkling possibilities under ACL are larger than without ACL acting in the earlier forming periods, and smaller in the later ones. （3） For the tubes with a size factor less than 80, the ACL roles in decreasing thinning degrees are stronger than in increasing wrinkling possibilities.

关键词： numerical control systems bending forming axial compression finite element modeling large-diameter Al-alloy thin-walled tubes

bending Stiffness of Truss-Reinforced Steel-Concrete Composite Beams

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Open Journal of Civil Engineering 2014年第3期4卷 285-300页

作者： Francesco Trentadue Erika Mastromarino Giuseppe Quaranta Floriana Petrone Giorgio Monti Giuseppe Carlo Marano Department of Civil Engineering and Architecture Technical University of Bari Bari Italy Metal.Ri s.r.l - via Giuseppe Abbruzzese 42 - 70020 Bitetto (BA) Department of Structural and Geotechnical Engineering Sapienza University of Rome Rome Italy Department of Civil and Environmental Engineering University of California Davis CA USA

This paper is concerned with a special steel-concrete composite beam in which the resisting system is a truss structure whose bottom chord is made of a steel plate supporting the precast floor system. This system works in two distinct phases with two different resisting mechanisms: during the construction phase, the truss structure bears the precast floor system and the resisting system is that of a simply supported steel truss;once the concrete has hardened, the truss structure becomes the reinforcing element of a steel-concrete composite beam, where it is also in a pre-stressed condition due to the loads carried before the hardening of concrete. Within this framework, the effects of the diagonal bars on the bending stiffness of this composite beam are investigated. First, a closed-form solution for the evaluation of the equivalent bending stiffness is derived. Subsequently, the influence of geometrical and mechanical characteristics of shear reinforcement is studied. Finally, results obtained from parametric and numerical analyses are discussed.

关键词： bending Stiffness Steel-Concrete Composite Beams Precast Floor Systems

bending and Vibrations of a Thick Plate with Consideration of Bimoments

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Journal of Applied Mathematics and Physics 2016年第8期4卷 1643-1651页

作者： Мakhamatali K. Usarov Davronbek М. Usarov Gayratjon T. Ayubov Institute of Seismic Stability of Structures of the Academy of Sciences of the Republic of Uzbekistan Tashkent Uzbekistan

The paper is dedicated to the development of the theory of orthotropic thick plates with consideration of internal forces, moments and bimoments. The equations of motion of a plate are described by two systems of six equations. New equations of motion of the plate and the boundary conditions relative to displacements, forces, moments, and bimoments are given. As an example, the problems of free and forced oscillations of a thick plate are considered under the effect of sinusoidal periodic load. The problem is solved by Finite Difference Method. Eigenfrequencies of the plate are determined, numeric maximum values of displacements, forces and moments of the plate are obtained depending on the frequency of external force. It is shown that when the value of the frequency of external effect approaches the eigenfrequency, there occurs an increase in displacement, force and moment values;that testifies a gradual transition of the motion of plate points into the resonant mode.

关键词： Plate Orthotropic Isotropic Displacement Stress Moment Bimoment bending Vibrations

Study on size-dependent bending behavior of axially functionally graded microbeams via nonlocal strain gradient theory

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Journal of Southeast University(English Edition) 2019年第4期35卷 453-463页

作者： Kang Zetian Wang Zhiyong Zhou Bo Xue Shifeng College of Pipeline and Civil Engineering China University of Petroleum(East China)Qingdao 266580China

Based on the nonlocal strain gradient theory(NSGT),the static bending behaviors of an axially functionally graded(AFG)Bernoulli-Euler microbeam subjected to concentrated and distributed loads are *** material property of the AFG microbeam changes continuously along the longitudinal *** the basis of the minimum potential energy principle,the equations of motion and associated classical and non-classical boundary conditions are ***,Galerkin’s weighted residual method in conjunction with the normalization technique are utilized to solve the governing differential *** transverse deformations of the AFG microbeam suffering the sinusoidal distributed load within the framework of NSGT,nonlocal elasticity theory(NET),strain gradient theory(SGT)and classical elasticity theory(CET)are *** is observed that the bending flexibility of the microbeam decreases with the increase in the ratio of the material length scale parameter to the beam ***,the bending flexibility increases with the increase in the material nonlocal *** functionally graded parameter plays an important role in controlling the transverse *** study provides a theoretical basis and a technical reference for the design and analysis of AFG micro-beams in the related regions.

关键词： axially functionally graded microbeam nonlocal strain gradient theory bending Galerkin method normalization method