简支梁绝对最大弯矩的一种新解法

用最不利荷载位置来求解简支梁绝对最大弯矩,省略了梁中央截面最不利荷载的计算,并用影响线进行校核.     

简支梁的绝对最大弯矩

简支梁的绝对最大弯矩国艳红（吉林省城市建设学校专业基础教研室,吉林１３２００２）在设计承受移动荷载的结构时,须求出每一截面内力的最大值（最大正值和最大负值）．连接各截面内力最大值的曲线称为内力包络图．包络图是结构设计中重要的工具,在吊车梁、楼盖的连续...     

对压弯构件附加弯矩的研究

分析轴向力对压弯构件弯曲变形的影响,导出了轴向力对压弯构件引起的附加弯矩的一般表达式. 通过实例计算,定量分析了附加弯矩对压弯构件的最大弯矩的影响,得出了在实际问题中可否忽略附加弯矩的判别条件.     

结构力学教材中某教学内容的补充

给出了一组平行荷载直接沿着纵梁移动时,主梁承受结点荷载作用下绝对最大弯矩的计算方法. 从理论联系实际的角度,填补了现行结构力学教材中关于结点荷载作用下,计算主梁绝对最大弯矩的空白. 该内容若能够写入结构力学教材,将会使现行教材中影响线的内容安排上前后更能够良好地呼应,该问题的解决能更好地体现出影响线的工具性地位.     

组合变形中两个相互垂直面上弯矩的合成分析

从解析法和几何法两个方面,对材料力学组合变形中的两个相互垂直面上弯矩的合成问题作了深入分析.     

三铰拱弯矩影响线的图解法

介绍了三铰拱弯矩影响线的一种图解方法, 并给出了完整的证明.     

用VBA在AutoCAD上画平面杆系结构的弯矩图

 用VBA技术在AutoCAD 2000下画矩阵位移法计算后的平面杆系结构的弯矩图，描述 了两种单元荷载作用下的弯矩图的生成. 在AutoCAD下生成的弯矩图可很方便地在 打印机或绘图仪中输出.     

关于《船舶结构力学》的思考——————改革《船舶结构力学》教科书

介绍《船舶结构力学》教科书的过去和现在. 从阅读一本《船舶结构力学》教科书稿, 引起 对``结构'、``结构力学'、``船舶结构力学'等问题的思考. 提出改革《船舶结构力学》 教科书的建议, 并提出《船舶结构力学》教科书的主要内容及编写主线的意见.     

计算简支梁最大挠度的简单方法

提出利用悬臂梁法计算简支梁最大挠度的方法.先利用悬臂梁法计算简支梁端截面的转角.根据端面转角,确定最大挠度的截面位置,从而求出梁的最大挠度.本方法计算简支梁的最大挠度,既简单又快捷.     

理想桁架计算模式的精确性分析

通过对典型钢桁架因结点刚性所产生的次应力的计算,分析了理想桁架计算模式的精确程度,据此提出了钢桁架焊接设计的改进建议,并将其应用到教学实践中.     

Lateral-torsional buckling of simply supported beams under uniform bending and axial tensile force

In this paper, the effect of a centrally applied external axial tensile load on the lateral-torsional buckling resistance of simply supported I-beams under uniform bending acting in the plane of maximum rigidity is studied. A linear and a nonlinear analysis are performed. Following the linear analysis, an expression for the critical moment of lateral-torsional buckling is presented in which the influence of the axial tensile force is included. There is an upper limit of this force over which the equilibrium in the deformed state is not possible. In the nonlinear analysis, the nature of the critical state is studied, considering the initial part of the post-buckling path. It is concluded that this critical state is associated with a stable symmetrical bifurcation point. Nevertheless, the post-buckling path is very shallow; therefore, the beam cannot exhibit practically post-buckling strength. The paper is supplemented by a representative example.     

NONLINEAR BENDING OF SIMPLY SUPPORTED RECTANGULAR SANDWICH PLATES

In this paper,fundamental equations and boundary conditions of the nonlinearbending theory for a rectangular sandwicl plate with a soft core are derived by meansof the method of calculus of variations.Then the nonlinear bending for a simplysupported rectangular sandwich plate under the uniform lateral load is investigated byuse of the perturbation method and a quite accurate analytic solution is obtained.     

Nonlinear bending of simply supported symmetric laminated cross-ply rectangular plates

Based on the von Kármán-type theory of plates,nonlinear bending problems of simplysupported symmetric laminated cross-ply rectangular plates under the combined action ofpressure and inplane load are investigated in this paper.The solution which satisfies thegoverning equations and boundary conditions is obtained by using the double Fourier seriesmethod.     

基于物理中面FGM简支梁的弯曲行为

基于一阶非线性梁理论,利用物理中面概念导出了FGM梁的基本方程,分析了热载荷作用下简支FGM梁的弯曲行为.当坐标面置于功能梯度材料(FGM)梁的物理中面上时,其本构方程中,面内力与弯矩并不耦合,使得问题的控制方程以及边界条件得以简化.分析中假设功能梯度材料性质只沿梁厚度方向、并按成分含量的幂指数形式变化;利用打靶法数值地求解了所得方程.数值结果表明:热载荷作用下,夹紧FGM梁发生过屈曲变形,而简支梁则发生较为复杂的热弯曲变形;在同一热载荷作用下,简支FGM梁将会产生三种构形问题;剪切变形对夹紧FGM梁的热变形影响比简支梁更明显.     

Two-dimensional analytical solutions of simply supported composite beams with interlayer slips

A new plane stress model of composite beams with interlayer slips is developed by the state space method. By virtue of the method of Fourier series expansion, the solution is obtained analytically for beams with two simply supported ends, which rigorously satisfies the governing equations and the specified boundary conditions. The solution includes the effect of shear deformation and is two-dimensionally exact since no Euler–Bernoulli hypothesis of the deformation is introduced, which is usually assumed in the one-dimensional theory. The results obtained from the present two-dimensional method are compared with those available in literature based on the one-dimensional theory. Parametric studies on the rigidity of the shear connectors are also conducted.     

On the dynamic behaviour of elastic plastic beams simply supported and axially loaded

Summary An elasto-plastic beam-column model withn degrees of freedom statically loaded with an axial compressive force is considered. Its dynamic behaviour in the elasto-plastic range, resulting from the action of a transversal distributed force periodically varying in time in condition of resonance with the structure in the elastic range, is examined. The principal differences with previous results obtained with one degree of freedom model are showed.

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Sommario Si considera un modello adn gradi di libertà di un'asta elasto plastica sollecitata staticamente da una forza assiale di compressione. Se ne esamina la risposta, in campo elasto plastico, ad un carico trasversale distribuito, variabile con legge armonica ed in condizioni di risonanza con la struttura in campo elastico, evidenziando le principali differenze rispetto alle conclusioni tratte in precedenza utilizzando schemi ad un grado di libertà.

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The present investigation has been promoted and financed by the Consiglio Nazionale Ricerche (C.N.R.) at the Istituto di Scienza e Tecnica delle Costruzioni del Politecnico di Milano.     

混凝土三点弯曲梁软化特性的数值计算方法

本文推导了基于虚拟裂纹模型的混凝土梁荷载位移全曲线的计算公式,研究了不同网格剖分、不同的拉伸软化曲线模型和不同的预制裂纹长度等对荷载位移全曲线的影响。计算结果表明,其结果不受网格划分的影响,通过与实验结果对比,证明了其有效性。     

A close-form solution to simply supported piezoelectric beams under uniform exterior pressure

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