具有内悬臂的环板在两种不同荷载共同作用下的塑性极限分析

针对承受两种不同荷载的具有内悬臂环板的塑性极限分析问题，应用奇异函数给出一种分析方法。文中给出一些算例，由此显示出本文方法的简单方便性。     

内边界支承环板在边缘弯矩和线性荷载作用下塑性极限分析

<正> 1.计算方法简介对于环板,其平衡方程为式中(?)为环板内半径.对于内边界支承的环板,在最大弯矩极限条件下,其极限条件为 M_θ=-M_p,M_p,为塑性极限弯矩.于是,设     

环板在局部线性荷载作用下的塑性极限分析的计算方法探讨

本文结合环板在线性荷载作用下的极限分析问题，给出一种简便的计算方法，即奇异函数法。文中用此法计算了具有外边界或内边界支环板的极限荷载，并画出几何参数对极限荷载的影响曲线，所得的结果具有良好的规律性而且是比较合理的。     

环板在局部线性荷载作用下的塑性极限分析的计算方法探讨

本文结合环板在线性荷载作用下的塑性极限分析问题,给出一种简便的计算方法,即奇异函数法。文中用此法计算了具有外边界或内边界支承的环板的极限荷载,并画出几何参数对极限荷载的影响曲线。所得的结果具有良好的规律性而且是比较合理的。     

输电钢管塔环板节点极限承载力的理论研究

以圆环-母线梁模型为基础,运用虚功原理,研究了无环板和四分之一环板节点极限承载力的计算方法,并给出了节点极限承载力的建议公式.通过将其与试验结果、有限元计算结果、日本铁塔协会的送电用钢管铁塔制作基准的计算结果进行对比,证明本文所提出的建议公式得到的结果较日本铁塔协会的送电用钢管铁塔制作基准的计算结果有所提高,并能较好地与试验和有限元计算的结果吻合,与试验结果的误差约为3%.本文可为超高压输电钢管塔节点设计和节点极限承载力确定提供参考.     

用广义阶梯函数简化计算简支圆板在复杂荷载作用下的极…

本文将广义阶梯函数应用于薄板的塑性极限分析问题，用以简化计算简支圆板在复杂荷载作用下的极限荷载。文中针对简支圆板在任意局部均布荷载和线性分布荷载共同作用下的塑性极限分析问题，并考虑荷载的五种不同的分布形式，给出相应的极限荷载的计算公式。     

用加权余量法分析固支圆板和环板在Mises屈服条件下的极限荷载

应用加权余量法求出了承受线性荷载的固支圆板和承受均布荷载的内边界支承环板在 Mises屈服条件下的极限荷载的近似值 ,并与最大弯矩极限条件结果进行了比较 ,说明本文计算结果较合理。     

用广义阶梯函数简化计算简支圆板在复杂荷载作用下的极限荷载

本文将广义阶梯函数应用于薄板的塑性极限分析问题，用以简化计算简支圆板在复杂荷载作用下的极限荷载。文中针对简支圆板在任意局部均布荷载和线性分布荷载共同作用下的塑性极限分析问题，并考虑荷载的五种不同的分布形式，给出相应的极限荷载的计算公式。     

悬臂矩形板的对称弯曲

本文用瑞次(Ritz)法研究了悬臂矩形板受均布载荷或集中载荷作用时的对称弯曲问题.选取多项式作为挠曲函数.算例表明,本文结果比文献[2]更加精确,计算过程也十分简单.     

考虑尺寸效应板梁的磁弹性屈曲

研究表明,有限尺寸效应是影响板——梁磁弹性稳定性分析精度的主要原因。本文用边界元法分析了板边沿的磁感强度集中,然后用里兹法计算了软铁磁材料悬臂板——梁的临界屈曲磁场。通过和Moon-Pao的理论和实验结果以及Miga的有限元结果比较,表明本方法具有良好的精度,且计算方法简便。     

Dynamics of a partially confined,discharging, cantilever pipe with reverse external flow

The potential for fluid-elastic instability of hanging cantilevered pipes subjected to simultaneous internal and external axial flows is investigated. Such systems may lose stability by amplified oscillations (flutter) or buckling (static divergence). The system of interest is a flexible tubular cantilever hanging concentrically within a rigid outer tube of larger diameter. Flow inside the cantilever is directed from the clamped end to the free end. Upon exiting the cantilever, the fluid flows in the opposite direction in the annular region between the outer tube and the cantilever. The rigid outer tube is of variable length and it can cover part of the length of the cantilever. This system has applications in brine production and salt-cavern hydrocarbon storage. A linear model is derived based on the work of Paidoussis, Luu and Prabhakar; the presence of the shorter outer rigid tube is taken into account in a simplified way. Series solutions are obtained using a Galerkin method with Euler–Bernoulli beam eigenfunctions as comparison functions. Experimental results are presented and compared with the theoretical model. Additional computations are performed to quantify the effect of confinement (i.e. the narrowness of the annular region) on the cantilever stability, as well as the effect of confined-flow length, for both the short laboratory-sized system and long brine-string-like systems. An increase in these parameters gives rise to flutter for short systems, or a succession of flutter and divergence for long systems. In addition, the effect of the system length is investigated. Increasing length results in asymptotic behaviour, with both the critical flow-velocity and associated frequency reaching limiting values. Sufficiently long systems lose stability by divergence rather than flutter.     

Dynamics of a long tubular cantilever conveying fluid downwards,which then flows upwards around the cantilever as a confined annular flow

A theoretical model is developed for the dynamics of a hanging tubular cantilever conveying fluid downwards; the fluid, after exiting from the free end, is pushed upwards in the outer annular region contained by the cantilever and a rigid cylindrical channel. This configuration thus resembles that of a drill-string with a floating fluid-powered drill-bit. The linear equation of motion is solved by means of a hybrid Galerkin–Fourier method, as well as by a conventional Galerkin method. Calculations are conducted for a very slender system with parameters appropriate for a drill-string, for different degrees of confinement of the outer annular channel; and also for another, bench-top-size experiment. For wide annuli, the dynamics is dominated by the internal flow and, for low flow velocities, the flow increases the damping associated with the presence of the annular fluid. For narrow annuli, however, the annular flow is dominant, tending to destabilize the system, giving rise to flutter at remarkably low flow velocities. The mechanisms underlying the dynamics are also considered, in terms of energy transfer from the fluid to the cantilever and vice versa, as are possible applications of this work.     

用Mises屈服条件求内边界简支环板在线性荷载作用下的极限荷载

应用Mises屈服条件分析内边界简支环板在线性荷载作用下的极限荷载．考虑到Mises屈服条件的非线性，文中应用加权余量法进行分析．针对线性荷载的不同分布形武，给出极限荷载的计算公武与数值结果，画出极限荷载的影响曲线，并与最大弯矩极限条件的数值结果进行了比较，说明结果是合理的．     

悬臂梁振动可靠性分析的研究

本文把悬臂梁的固有频率、激振力频率、平均应力、应力幅和疲劳极限处理为随机变量，提出了悬臂梁在强迫振动时不发生共振和疲劳损坏的可靠性分析方法。     

环板在两种不同荷载共同作用下的塑性极限分析

本文针对外边界支承环板的塑性极限分析问题,应用奇异函数给出一种简便的分析方法,并分四种情况给出环板在两种不同荷载共同作用下的极限荷载的计算公式。     

Effect of nonhomogenous material properties on transverse vibrations of elastic cantilevers

In this paper, the method of the influence functions and the method of partial discretization are proposed to solve the boundary-value problem of free transverse vibrations of a nonhomogenous cantilever with a concentrated mass attached to the free end. In order to demonstrate the possibilities of the methods, the case of a cantilever in the form of a sharp cone, a frustum of a cone, and a linear wedge made of two different materials is treated in detail. The general characteristic equations which allow one to take into consideration the nonhomogeneous material properties and the cross-sectional geometry of cantilever are introduced. The expressions for the first three terms of the characteristic series are obtained in closed form using the method of Cauchy influence functions. The results of calculations of the first two frequencies of free transverse vibrations are presented for selected material combinations and various cantilever geometries. There is very good agreement between the numerical results obtained using the method of partial discretization and the analytical results obtained using the method of influence functions. The high accuracy of the proposed methods and agreement with known theoretical data and with the experimental results obtained by the authors in the homogeneous cantilever case are shown. Presented at the International Conference on the Theory of Machines and Mechanisms, Poland, 1996. Published in Prikladnaya Mekhanika, Vol. 35, No. 6, pp. 103–110, June, 1999.     

用奇异函数法简化计算环板的极限荷载

本文首次将奇异函数法应用于结构的塑性极限分析,并用以计算某些环形板的极限荷载。该法的优点是概念清楚,简单易行.