SOME RESULTS ON CONTINUOUS TYPE CONDITIONAL INPUT-OUTPUT EQUATION-FIXED POINT AND SURJECTIVITY METHODS

Based on the classical ( matrix type ) input-output analysis, a type of nonlinear ( continuous type) conditional Leontief model, input-output equation were introduced, as well as three corresponding questions, namely, solvability, continuity and surjectivity , and some fixed point and surjectivity methods in nonlinear analysis were used to deal with these questions. As a result, the main theorems are obtained, which provide some sufficient criterions to solve above questions described by the boundary properties of the enterprise‘s consuming operator.     

A note on a theorem of Tas, Telci and Fisher

I.IntroductionInarecentpaperTas,TelciandFisherlZ],obtainedthefollowingimprovedandgeneralizedversionofafixedpointtheoremofSharmaandSahulll:TheoremALet.A,B,SandTbeselfmappillgsonacompletemetricspace(X,ti,satisfyingA(X)GT(X)andB(X)GS(X)(l.l)[d(Ax,By)]2$Clmax{[d(Sx,Ax)]',[d(Ty,By)jZ,[d(Sx,Ty)]2} cd.max{d(Sx,Ax).d(Sx,By),d(Ax,Ty).d(By,Ty)} c,.d(Sx,By).d(Ty,As)(1.2)t'orallx,yinX,whereof,cZ,c3>0,of 2c2相似文献   

Forced nonlinear oscillations of semi-infinite cables and beams resting on a unilateral elastic substrate

In this work, we study the nonlinear oscillations of mechanical systems resting on a (unilateral) elastic substrate reacting in compression only. We consider both semi-infinite cables and semi-infinite beams, subject to a constant distributed load and to a harmonic displacement applied to the finite boundary. Due to the nonlinearity of the substrate, the problem falls in the realm of free-boundary problems, because the position of the points where the system detaches from the substrate, called Touch Down Points (TDP), is not known in advance. By an appropriate change of variables, the problem is transformed into a fixed-boundary problem, which is successively approached by a perturbative expansion method. In order to detect the main mechanical phenomenon, terms up to the second order have to be considered. Two different regimes have been identified in the behaviour of the system, one below (called subcritical) and one above (called supercritical) a certain critical excitation frequency. In the latter, energy is lost by radiation at infinity, while in the former this phenomenon does not occur and various resonances are observed instead; their number depends on the statical configuration around which the system performs nonlinear oscillations.     

On the Problem of Dissipative Perturbations of Nonexpansive Mappings

ＩｎｔｒｏｄｕｃｔｉｏｎａｎｄＰｒｅｌｉｍｉｎａｒｉｅｓＴｈｒｏｕｇｈｏｕｔｔｈｉｓｐａｐｅｒ,ｗｅａｓｓｕｍｅｔｈａｔＨｉｓａｒｅａｌＨｉｌｂｅｒｔｓｐａｃｅ ,〈· ,·〉ｉｓｔｈｅｉｎｎｅｒｐｒｏｄｕｃｔｏｎＨ ,ＰｉｓａｃｏｎｅｉｎＨ .ＢｙｖｉｒｔｕｅｏｆｔｈｅｃｏｍｅＰ ,ａｎｏｒｄｅｒ“≤”ｉｓｉｎｄｕｃｅｄｉｎＨ ,ｉ.ｅ .,ｆｏｒａｎｙｇｉｖｅｎｘ,ｙ∈Ｈ ,ｘ≤ｙｉｆａｎｄｏｎｌｙｉｆｙ -ｘ∈Ｐ .Ａｍｕｌｔｉ＿ｖａｌｕｅｄｍａｐｐｉｎｇＡ :Ｄ(Ａ) Ｈ → 2 Ｈｉｓｓａｉｄｔｏｂｅａｃｃｒｅｔｉｖ…     

非线性弹性大变形材料梁的抗爆特性

从理论上探讨了非线性弹性大变形材料应用于抗爆结构的可行性,为此,基于等效结构体系的分析原理,将两端固定铰支梁的横向和纵向位移表示为三角级数形式,应用第二类Lagrange方程建立了非线性大变形材料梁的非线性分析方法,并且用ABAQUS有限元软件中的超弹性材料模型验证了所提出的方法的有效性。对典型的爆炸荷载作用下非线性弹性大变形材料梁的抗爆特性进行了分析,讨论了动力放大系数和材料性质及动荷载之间的关系。结果表明:与线弹性小变形材料相比,非线性弹性大变形材料具有优良的抗爆特性,结构的抗爆能力随结构变形的增大而显著提高。     

Subharmonic and ultra-subharmonic response of nonlinear elastic beams subjected to harmonic excitation

Ｔｈｅｄｙｎａｍｉｃｒｅｓｐｏｎｓｅｐｒｏｂｌｅｍｓｏｆｅｌａｓｔｉｃｓｔｒｕｃｔｕｒｅｈｏｌｄｍｏｒｅａｎｄｍｏｒｅｉｎｔｅｒｅｓｔ．Ｉｎｔｈｅｅａｒｌｙ１９７０’ｓ．Ｗ．Ｙ．Ｔｓｅｎｇｅｔａｌ．［１,２］ｉｎｖｅｓｔｉｇａｔｅｄｆｉｘｅｄ＿ｅｎｄｅｄｂｅａｍｓ．Ｆｉｒｓｔ,ｔｈｅｓｉｎｇｌｅｍｏｄｅａｎｄｔｗｏｍｏｄｅｓｗｅｒｅｕｓｅｄｔｏｔｒａｎｓｆｏｒｍｐａｒｔｉａｌｄｉｆｆｅｒｅｎｔｉａｌｃｏｎｔｒｏｌｌｉｎｇｅｑｕａｔｉｏｎｓｉｎｔｏｏｒｄｉｎａｌｄｉｆｆｅｒｅｎｔｉａｌｄｙｎａｍｉ…     

An iteration method for integral equations arising from axisymmetric loading problems

Let the concentrated forces and the centers of pressure with unknown density functions x(ξ) and y(ξ) respectively be distributed along the axis z outside the solid, then one can reduce an axismmetric loading problem of solids of revolution to two simultaneous Fredholm integral equations. An iteration method for solving such equations is duscussed. A lemma equivalent to E. Rakotch’s contractive mapping theorem and a theorem concerning the convergent proof of the iteration method are presented.     

Existence theory for Rosseland equation and its homogenized equation

The global boundness and existence are presented for the kind of the Rosseland equation with a general growth condition.A linearized map in a closed convex set is defined.The image set is precompact,and thus a fixed point exists.A multi-scale expansion method is used to obtain the homogenized equation.This equation satisfies a similar growth condition.     

Asymptotic analysis of layered elastic beams

We consider an elastic beam formed by three layers, fixed at one end and loaded at the free end. We call adherents the upper and lower layers ${\Omega }_{+}^{?}$ and ${\Omega }_{?}^{?}$ and an adhesive layer ${\Omega }_m^{?}$. We denote by $?h_{\pm ,m}$ the thickness of each layer and we suppose that the stiffness of the adhesive layer is ${?}^2$, with respect to that of the adherents. By an asymptotic analysis we obtain the zeroth order limit problem and the form of the second order displacements. To cite this article: M. Serpilli, C. R. Mecanique 333 (2005).     

Solution of nonlinear wave equation of elastic rod

The longitudinal oscillation of a nonlinear elastic rod with lateral inertia are studied. A nonlinear wave equation is derived. The equation is solved by the method of full approximation.     

PERTURBATION ANALYSIS FOR WAVE EQUATION OF NONLINEAR ELASTIC ROD

The longitudinal oscillation of a nonlinear elastic rod with lateral inertia was studied. Based on the far field and simple wave theory, a nonlinear Schrodinger (NLS) equation was established under the assumption of small amplitude and long wavelength. It is found that there are NLS envelop solitons in this system. Finally the soliton solution of the NLS equation was presented.     

The symmetrical bending of an elastic circular plate supported atK internal points

This paper treats the symmetrical bending of a uniformly loaded circular plate supported at k internal points. The boundary displacement and slope are expanded in Fourier seriesr. The method proposed by [6] is applied. As both the governing differential equation and boundary conditions are satisfied exactly, we therefore obtain the analytic expression of the transverse deflectional equation of the circular plate. This is an easy and effective methed.     

On axisymmetric motion of an incompressible elastic medium under impact loading

The method of matched asymptotic expansions was employed to obtain approximate solutions to the one-dimensional boundary-value problems of nonlinear dynamic elasticity theory of impact loading on the surface of a cylindrical cavity of an incompressible medium that causes antiplane motion or torsion of the medium. The expansion of the solution in the near-front region is based on solutions of evolution equations different from the equations for quasi-simple waves. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 6, pp. 144–151, November–December, 2006.     

Solution of spline function of elastic plates

In this paper.from four and three-order differential equations defined by cubic andquadratic splines of generaized beam.The beam functions with many boundary conditionsand under various loads are reduced.The approximate solution of deformation surface andstress of elastic thin plate is very accurate.     

Problem of periodic solutions for neutral functional differential equation

ＩｎｔｒｏｄｕｃｔｉｏｎＬｅｔＣ(ｋ- 1)2π =ｈ(ｔ) ｜ｈ :Ｒ →Ｒｉｓ (ｋ -1 )＿ｔｈｏｒｄｅｒｃｏｎｔｉｎｕｏｕｓｄｉｆｆｅｒｅｎｔｉａｂｌｅａｎｄｈ(ｔ+ 2π) ≡ｈ(ｔ) ,　　Ｃ2π =ｈ(ｔ) ｜ｈ :Ｒ →Ｒｉｓｃｏｎｔｉｎｕｏｕｓａｎｄｈ(ｔ+ 2π) ≡ｈ(ｔ) ,　　‖ｈ(ｔ)‖ =ｓｕｐｔ∈ [0 ,2π] ｜ｈ(ｔ) ｜ ,　　‖ｈ(ｔ)‖Ｐｋ- 1 =ｍａｘ‖ｈ(ｔ)‖ ,‖ｈ′(ｔ)‖ ,… ,‖ｈ(ｋ- 1) (ｔ)‖ ,　　ｘ(ｍ) (ｔ+ ·) (θ) =ｘ(ｍ) (ｔ+θ)　　θ∈Ｒ (ｍ =0 ,1 ,2 ,… ,ｋ-1 ) .Ｃｌｅａｒｌｙ ,ｘ(ｍ) (ｔ + ·) ∈Ｃ2π, …     

Global analysis of secondary bifurcation of an elastic bar

In a three dimensional framework of finite deformation configurations, this paper investigates the secondary bifurcation of a uniform, isotropic and linearly elastic bar under compression in a large range of parameters. The governing differential equations and finite dimensional equations of this problem are discussed. It is found that, for a bar with two ends hinged, usually many secondary bifurcation points appear on the primary branches which correspond to the maximum bending stiffness. Results are shown on parameter charts. Secondary modes and branches are also calculated with numerical methods. The project supported in part by the National Natural Science Foundation of China     

计及剪切影响的RC梁的非线性分析

为提高钢筋混凝土RC梁的计算效率和精度,提出了一种基于梁截面弯矩-曲率关系的宏观有限元方法,可用于各种跨高比RC梁的材料非线性分析。首先假定了混凝土和钢筋的非线性应力-应变关系,然后引入经过修正的Rodriguez截面模型,根据边界顶点把截面划分成若干梯形单元,利用quasi-Newton法求解由两个变量耦合而成的截面非线性平衡方程,由此建立RC截面的弯矩-曲率关系。在此基础上利用Timoshenko梁弯曲理论建立考虑横向剪切变形影响的RC梁的有限元分析模型。通过对试验梁的分析对比验证了所提出的分析方法的适用性。     

钢-混凝土组合梁非线性有限元分析

提出了部分剪力连接钢-混凝土组合梁非线性有限元分析的简化模型,该模型同时考虑了钢、混凝土材料的非线性本构关系和剪力连接件的滑移非线性对组合梁刚度和强度的影响,推导了考虑滑移的剪力连接件单元刚度矩阵。利用该模型计算了连续组合梁的极限荷载、挠度、应力以及滑移,与已有的理论计算结果和实验结果吻合,证明本方法分析钢-混凝土组合梁非线性的可靠性和实用性。     

Periodic behavior of a nonlinear dynamical system

Nonlinear dynamical systems, being more of a realistic representation of nature, could exhibit a somewhat complex behavior. Their analysis requires a thorough investigation into the solution of the governing differential equations. In this paper, a class of third order nonlinear differential equations has been analyzed. An attempt has been made to obtain sufficient conditions in order to guarantee the existence of periodic solutions. The results obtained from this analysis are shown to be beneficial when studying the steady-state response of nonlinear dynamical systems. In order to obtain the periodic solutions for any form of third order differential equations, a computer program has been developed on the basis of the fourth order Runge-Kutta method together with the Newton-Raphson algorithm. Results obtained from the computer simulation model confirmed the validity of the mathematical approach presented for these sufficient conditions.