屈曲

Under uniaxial pressure, piezolectric effect and external voltage can hardly affect buckling and post-buckling charact eristic of piezoelectric-plate.

计算结果表明，在单向压力作用下，材料的压电效应和外加电压对板的屈曲载荷及后屈曲影响很小；而电场对位移加载简支板的屈曲影响较显著。

In chapter 2, a finite element model for the composite sandwich plates is developed, based on the Zig-Zag deformation assumption and the first order shear deformation theory, and the finite element buckling analysis governing equations for the plates under mechanical, thermal and/or thermal-mechanical mixed loads are deduced respectively. By Von-Karman nonlinear deformation relations and Total Lagrange formulation, an incremental governing equation for postbuckling analysis is established and a corresponding effective computational scheme is presented..

第二章首先建立了基于Zig-Zag截面变形假定和Mindlin一阶剪切理论的夹层板有限元分析模型，分别推导了夹层板机械力、热载和热—机械力耦合屈曲分析的有限元列式和相应的屈曲前以及屈曲临界状态的平衡方程，基于Von-Karman大挠度理论，采用增量形式的全局lagrangian法推导了复合材料夹层板增量形式的几何非线性有限元离散平衡方程，给出了一种有效的非线性平衡方程的迭代求解格式。

This paper mainly consists of three parts:(1) Based on the Reddy's higher-order shear deformation plate theory and general von Kármán-type equations, put forward the governing equations of pre- and post-buckled vibration of several hybrid FGM plate forms which have not been studied adequately, triumphantly applying the perturbation technique combined with Galerkin method into equations solving, and get the comparatively simple result forms with complicated deduction at last;(2) As a new type of materials, piezoelectric fiber reinforced composite actuators were applied to optimal vibration control, interrelated informatons be depicted in this paper;(3) During the investigative cource, some factors not been considered adequently in other researches were discussed fully in the postbuckled vibration analysis, such as the temperature-dependent material coefficients, heat conduction and nonlinear vibration characteristic etc.

本文的研究工作主要包括：(1)基于Reddy高阶剪切变形板理论和广义Kármán型方程，给出了几类现有研究成果较少或没有彻底解决的FGM混合板结构的屈曲前和屈曲后振动特性研究的控制方程，成功将摄动-Galerkin混合法应用于求解过程，并给出了各控制方程相对直观且易于计算的解析解形式；(2)单向压电纤维增强复合材料(Piezoelectric Fiber Reinforced Composite，简称PFRC)是一种新型压电材料，本文将其应用到了结构振动控制研究当中，发现通过压电纤维体积含量的选择可以实现混合板结构的优化振动控制；(3)围绕几种有代表性的FGM混合板结构，讨论其屈曲后的振动特性，在分析中同时考虑热传导，材料物性参数的温度相关性，以及机/热/电荷载耦合效应对非线性振动特性的影响，最后给出了大量数值计算结果。

Based on the magnetic-elasticity nonlinear kinetic equations, physical equations, electrical kinetic equations and the expression of Lorentz forces, the magnetic-elasticity kinetic buckling equation of a current-carrying plate applied mechanical load in a magnet field were derived. The equation was transformed into the standard Mathieu equation by using Galerkin method. Thus, the magnetic-elasticity kinetic problem was changed into a problem of solving the Mathieu equation.

在载流薄板的磁弹性非线性运动方程、物理方程、洛仑兹力表达式及电动力学方程的基础上，导出了载流薄板磁弹性动力屈曲方程，并应用Galerkin原理把屈曲方程整理为Mathieu方程的标准形式，将载流矩形薄板在电磁场与机械荷载共同作用下的磁弹性屈曲问题归结为对Mathieu方程的求解问题。

Based on the magneticelasticity nonlinear kinetic equations, physical equations, electrical kinetic equations and the expression of Lorentz forces, the magneticelasticity kinetic buckling equation of a currentcarrying plate applied mechanical load in a magnet field were derived. The equation was transformed into the standard Mathieu equation by using Galerkin method. Thus, the magneticelasticity kinetic problem was changed into a problem of solving the Mathieu equation.

在载流薄板的磁弹性非线性运动方程、物理方程、洛仑兹力表达式及电动力学方程的基础上，导出了载流薄板磁弹性动力屈曲方程，并应用Galerkin原理把屈曲方程整理为Mathieu方程的标准形式，将载流矩形薄板在电磁场与机械荷载共同作用下的磁弹性屈曲问题归结为对Mathieu方程的求解问题。

On the basis of this , the paper makes a great deal of calculation and analysis in this part , different parameters effect and stress gradient are included . local buckling coefficient and the efficient width calculated formula are provided and look forward to take a reference to the redaction of the specification

本文对此内容进行了较为深入的研究，考虑了多个参数的影响，对各种应力比作用下的楔形腹板的屈曲及屈曲后强度进行了计算分析，得出了考虑翼缘相关作用的楔形腹板屈曲系数及有效宽度系数的计算公式，以期为规范的修订提供参考。

I learned a lot of thing on the conference, such as used in steel buckling analysis marco element theory, named GBT, it can predict the global buckling modal including local buckling modal, it's amazing. then, I meet a professor form Roumania, He also have some researches on marco element, we talk a lot.

会议上学到了很多东西，也认识了一些牛人，从报告中发现，宏观单元不但是混凝土中用了，在分析钢结构的屈曲问题也用到，如GBT单元，可以通过截面屈曲模态去计算整体屈曲变形，简直是神乎奇技，认识了罗马尼亚的教授，也是搞宏观单元编程的，谈了很多。

Aiming at the problem of buckling stability capability of box section hoist boom of wheel crane, a complete section of hoist boom is taken as analysis object and buckling instability of the webs is analyzed and researched with the booms of different sectional shapes by applying finite element analysis method. Compared with crane design code (GB3811-83), one piece of plate is taken to calculate buckling stability, the method is easier and more accurate and calculation and analysis of complicated sectional shapes are easy to conduct.

针对轮式起重机箱型起重臂的抗屈曲失稳能力问题，采用有限元分析方法，取起重臂截面半波长段作为分析对象，对相同工况不同截面形状的起重臂的屈曲失稳情况进行分析研究，相对于起重机设计规范(GB3811-83)给出的取一块板进行屈曲计算要快捷、准确得多，而且也容易完成对复杂形状截面的计算分析。

Impact buckling which has few study findings relatively. So some viewpoints have not been consistent. Systematic study is made on dynamic buckling of axial compression member under impact load in this paper for that reasons.

动力屈曲问题由于时间参数的引入相比静力屈曲问题要复杂得多，特别是对冲击荷载作用下的动力屈曲问题尤甚，研究成果相对较少，对许多问题的认识尚未达成一致。

The length of the anterior bundle was maxium at 90° of the elbow flexion, the length of the posterior bundle varied with the change of the angle of elbow flexion, and a transverse bundle was unchanged.

前束在肘关节屈曲90°时最长，此时亦为最紧张状态，后束则随肘关节屈曲角度增大而逐渐变长，而斜束的长度不随肘关节屈曲角度的变化而变化。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。