失稳

By making theoretical analysis on vibration characteristics of a single slab and multi ones set in the inverted arch ring, four processes about stability failure, that is free vibration, locking, sleeking and distortion are proposed on the condition that water sealing was damaged and anchor-hold was out of action, a formula of the slab's maximum free displacement and dynamic equations in each process are obtained.

对反拱水垫塘单底板块和多底板块振动特性进行了理论分析，提出了拱圈底板块失稳分为自由振动、锁定、滑动变形及拱圈失稳四个过程，给出了各振动过程的动力学方程以及底板块自由振动的最大理论高度的计算公式。

The basic study content of this essay is follow as:1.To calculate the stable factor k_i~0 of individual slices according to self-forced condition of slices,under the condition of without inter-slices force.2.To calculate transferal force R_i, stabile factor K_i of individual slices and stabile factor K of the stable slope, under the condition of there is a level transferal force between slices and the slope is stable. If the slope is not stable, to calculate the transferal force R_i between individual slices, the stabile factor K_i of individual slices and the stable factor K of the unstable slope in term of concordant conditions of acceleration.

本文研究的基本内容包括： 1、研究土条条间不传递力情况下，由土条自受力状态计算各土条的稳定系数K_i，并由K_i计算稳定土坡的稳定系数K； 2、研究条间传递水平力情况下，若土坡稳定，由土条预平衡状态、传力顺序和传力边界条件，推导各土条间的水平传力R_i的理论公式和各土条的稳定系数K_i，并由K_i计算稳定土坡的稳定系数K；若土坡失稳，由加速度和谐条件计算各土条间的水平传力R_i和各土条的稳定系数K_i，并由K_i计算失稳土坡的稳定系数K

Numerical simulations are conduced for the deformation, instability and failure of aluminum honeycombs with different relative density. The meso-mechanisms of instability and failure are analyzed.

数值模拟了不同相对密度范围的铝蜂窝结构的变形、失稳和破坏现象，分析了结构失稳和破坏的细观力学机制。

We, in this paper, combined the finite elements analysis with space similar material analogy test, studied the stability of the un-supported enclosing rock section during the comprehensive operation construction of the vertical coal shafts, analyzed the distribution laws of enclosing rock strain and surface radial displacement, hereby studying the un-supported height influence upon the enclosing rock.

本文将有限元分析和空间相似材料模拟试验相结合。对煤矿立井应用混合作业方式施工时未支护段围岩稳定性进行了研究，分析了围岩应力及表面径向位移的分布规律，研究了围岩失稳形式及失稳规律，并由此研究了未支护段高度对围岩稳定性的影响。

From the angle critical force ,this thesis analyses the stability of the formation of axle shaft spline in the extrusion and the calculation of the constraints available after losing stability.

从临界力的角度入手分析花键半轴在挤压成形时的稳定性及失稳后可增加约束的计算，研究表明半轴花键实现精密挤压成形不稳定时可增加约束来解决失稳问题。

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。

By analyzing surrounding rock instability caused by tunnel excavation, surrounding rock instability of deep-buried tunnels is considered as a sudden failure phenomenon, which possesses nonlinearity and discontinuity obviously and shows the uncertainty of mechanical deformation property, nonlinearity of constitutive relationship and catastrophe of failure process.

在分析隧道开挖引起围岩失稳基础上，认为深埋隧道围岩的失稳是一种突发破坏现象，具有明显的非线性和不连续性质，主要表现在力学变形性质的不确定性、本构关系的非线性和破坏过程中的突变性。

The following exciting results are derived: 1 When considering the influence of some nonlinear elements such as hard-limit of exciters, the effects of some devices such as Power System Stabilizer, Unified Power Flow Controller and Static Var Compensator as well as using real parameter values of power systems in simulation , the SNB surface and the HB surface on the boundary of small signal stability region will turn close to each other and even coalesce together; 2 Under some conditions, coupling between slow exciters and shunt capacitors will bring negative damping in power system dynamics, which increases the possibility of oscillatory instability, so that a power system with mass shunt compensators is easily subjected to the oscillatory instability.

同时发现：1 系统中的慢速励磁，在某些情况下会与并联补偿电容器组产生负阻尼现象而显著降低系统的动态性能，大大增加系统出现振荡失稳的可能性；2 在采用较多并联电容器组补偿的电力系统中，更容易出现振荡型失稳。

In fact, the process of fuel breakup and atomization is a kind of instability phenomenon of the liquid jet. In order to increasing the oil surface area and promoting efficient combustion, the instability process of the jet is always used to make the fuel atomization in engineering.

燃油的分裂与雾化过程实际上是液体射流的一种失稳现象，在工程上常常利用射流的这种失稳过程来实现燃油的雾化，以增加燃油的表面积提高燃烧效率。

A cusp catastrophe model is presented to describe the behavior of sliding along one deep incompetent structural plane of a gravity dam foundation, and the sufficient conditions leading to instability are discussed. It is found that the instability of sliding relies mainly on the stiffness ratio k, the homogeneity index of the medium m and the geometry-mechanic parameter ξ and that the reliability of the traditional limit analysis method is deficient.

通过建立的模型分析，发现坝基滑动失稳主要取决于软弱面上复杂弹脆性介质和应变软化介质在应变软化拐点处的刚度比k、材料的均匀性指标m及几何－力学参数ξ；并给出了发生突变失稳的充分力学判据，指出传统的刚体极限平衡分析法存在一定的缺陷。

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。