失稳

The model of flexibility of cantilever area, local flatting, and buckling under a pressure load have been presumed. And the influence on flexibility of cantilever of different roller position has been analyzed theoretically.

针对所研究的问题，假设了管坯悬臂段挠曲、局部压扁和受压失稳的力学模型，并从力学上分析了辊轮位置对管坯悬臂段挠曲的影响。

Firstly, the author establish the functions of stability on the basis of the spline function method ,according to the theory of geometrical nonlinear and the theory of stability, educe the stability equation of structure based on variational principle, then carry through the flexuosity analysis of CFST arch.The big distortion geometrical nonlinear was considered by the stability equation,the author simplified the problem of geometrical nonlinear through ignored quadratic term and reserve the simple term, at last boiled down to solve the linear stability equation of eigenvalue .

利用样条函数方法、根据几何非线性变形理论和结构稳定性理论，先建立起结构稳定的泛函，再由变分原理导出结构的稳定方程，进行钢管混凝土拱屈曲分析；本文所建立的稳定方程考虑了几何非线性的大变形效应，通过忽略几何非线性的二次项，保留一次项，将几何非线性问题简化，最后归结为求解线性稳定问题的特征值稳定方程，建立了结构非线性静力稳定性问题的新算法及失稳类型判别准则。

The wind velocity of first order instability is obtained from the dynamic equilibrium relationship between aerodynamic force with dead weight and inertia force of membrane.

根据气动力与薄膜自重和惯性力之间的动力平衡关系获得了薄膜一阶失稳时的临界风速。

The multi-fracture propagating during the unstable propagation accounts for the phenomena of furcation at the ends of earthquake faults.

失稳扩展中多条裂纹系同时扩展是地震破裂中出现分叉和多点同时破裂的主要原因。

The GKS stability theorem for one-dimensional model of hyperbolic initial and boundary value problem, Trefethen's explanation and extension based on the concept of group velocity are generalized firstly. Another possible high-frequency instability mechanism in numerical realization of MTF is pointed out based on his explanation and extension, namely, coupling effect of outgoing harmonic wave along one direction and node motion in the other directions can reverse the energy propagation in multi-dimensional discrete grids.

本文概述了—维双曲型偏微分方程组初边值问题数值稳定性的GKS定理及Trefethen基于群速度概念对这一定理的解释和推广；并应用Trefethen的解释和推广指出了MTF在数值实现中可能出现的另一种高频失稳机制，即在多维离散网格中，沿某一空间方向的外行简谐波，由于与其他空间方向节点运动的耦合效应可以使能量传播方向反向。

The dispersivity of wave propagation implies that phase velocity of a single harmonic wave is a function of the angle frequency.

本论文基于上述耦合模型，对单轴应变一维情况讨论了非线性饱和-非饱和多孔介质中波传播过程的失稳现象和逸散性。

It is very important to study the mechanism and pattern of unstable failure of rock mass under high stress for deep mining engineering.

因此研究深部高应力下岩体失稳破坏的机理和规律对深部开采的安全性具有重要的现实意义。

In the experimental area, when the foundation pit was excavated, horizontal and vertical deflection of pile was found. If no effective measures were taken, it would result in instability of excavated pit and decrease of pile's bearing capacity.

试验区基坑开挖后发现桩头有上浮及偏移现象，若不采取有效措施则必然导致基坑开挖失稳及整个桩基的承载力下降。

The typical failures are hulking and fracture, and both of them are problems of instability.

成形过程中常见的缺陷是起皱和破裂，这两种缺陷的产生都和管的失稳有关。

The deformation mechanism is mainly the single-slip and cross-ship, the fracture mechanism is mainly the congregation of transgranular micro-hole, and large uniform deformation occurred before tough fracture, and therefore, the ability of plastic deformation and the mechanical properties of the material were remarkably improved. These fully indicate that the new melt-treatment developed in this work is an effective and advanced technique, and further testify that the improvement of metallurgical quality of the material is the key to enhance its mechanical properties, especially its plastic deformation performance. The results of tensile and compression tests at elevated temperature also indicate that the suitable hot-working temperature range is 400～450℃. 4. A steady-state plastic flow exists during the plastic deformation of the aluminum sheet used for pressure can at elevated temperature. A hyperbolic sine relationship can be satisfied between the steady-state flow stress and strain rate by introducing an Arrhenius term which involves some thermal activation parameters, i.

压力罐用铝材中的主要冶金缺陷为Al〓O〓夹杂物、气孔及富Fe杂质相；高效熔体处理显著改善了材料的冶金缺陷的存在形态，使含杂量明显减少、夹杂物尺寸变细小且分布均匀，富Fe杂质相变为细小、分布均匀的团球状或短棒状的复杂化合物，同时也明显细化了结晶组织；此外，由于高效熔体处理有效地减少了材料中裂纹萌生源数量，因而改变了材料的塑性变形微观过程及断裂方式，主要以单滑移和交滑移进行塑性变形，断裂方式为穿晶微孔聚集型，韧性断裂前产生了大量的均匀变形，不易出现变形失稳，从而显著提高了罐用铝材的塑变能力和力学性能。

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。