屈服的

The results of yield stress measurements at a constant temperature and holding time were also presented.

当变形温度及保温时间相同时，随着应变速率的升高，屈服应力明显增加。

The main results of the investigation are as following:(1) Some important criteria for the design of multi-layer structure are acquired: the ratio of the layer thickness to the contact diameter should be controlled to a value about 0.8; increasing the number of the gradient layers and elasticity modulus of the top layer would benefit to the yield strength and the stress status at the interface.（2）By means of molecular dynamics simulations for a indentation and sliding process, it is discovered that dislocations of 45 direction to the surface occur in the surfaces layer, which is correspond to the direction of the plastic flows observed in the macroscopic continuous medium. The irreversible deformation caused by the dislocation and the atom piles at the surface are responsible for the irreversibility of the force response. They are also the main factors for the friction generation. The temperature and the indentation velocity have significant effects on the deformation behaviors of the material of the surface layer. The yield strength would increase obviously if the indentation velocity is greater than 10 m/s.（3）A method to evaluate the fracture toughness of coating by estimating the crack-density functionβof a Wicker''s indentation was proposed. Meanwhile a new surface treatment technology was developed using non-equilibrium plasma.（4）A MD-FE hybrid method and corresponding software was developed to analysis the tribological behaviors for multiplayer system.

研究主要内容和结果有：（1）得到指导梯度膜设计的几个准则：控制膜层厚度与接触半径比在0.8左右为宜；适当增加梯度层层数和顶层弹性模量，有利于提高抗屈服能力和改善界面处的应力状态；（2）通过对嵌入和滑动摩擦过程的分子动力学模拟，发现表层产生一个与宏观连续介质的塑性流动方向观测一致的45 方向位错；位错造成的不可逆变形和表面的原子堆积，是力的响应不可逆性的原因，也是构成摩擦力的主要因素；温度和嵌入速度对材料变形特性有显著的影响，当嵌入速度大于10 m/s时，屈服强度明显增加；（3）提出压痕裂纹密度系数β半定量判定膜层断裂韧性的方法；并开发出表面强化新工艺；（4）开发出分析表面摩擦学特性的MD-FE复合模拟方法和相应模拟软件。

On the base of the analysis, the following standpoints are presented definitely. There is no such a so-called zone with low density near the inwall of the lining. Upon the explosion terminates, the mortar would lose characteristics of the fluid. The compression strength of the lining layer formed by explosion is higher than that of a reference block tested.

在假定材料服从Tresca屈服准则或Coulomb屈服准则的条件下，得到了圆形井筒和球形腔体最大扩张压力p〓的计算公式；衬砌材料塑性区应力σ〓、σ〓和土体塑性区的应力σ〓、σ〓的计算公式；土体弹性区的应力σ〓、σ〓和径向位移u〓的计算公式；衬砌材料与土体交界面半径R〓以及土体中弹塑性区交界面半径R〓的计算公式。

In order to analyze rheological property and establish constitutive model of Q_2 loess, a series of uniaxial creep experiments on different water content are done .The creep test curves and stress-strain isochronism curves are drawed with the result of experiments and conclusions are reached from the curves. The creep performance of Q_2 loess is different under the different stress level. In the different time the stress-strain isochronism curve has obvious inflection point namely yield stress and the yield stress reduces along with the increase of water content, which can be described by exponential function.

为了分析黄土的流变特性和建立相应的本构模型，本文首先根据对不同含水量的Q_2黄土进行的一系列单轴应力条件的室内蠕变试验结果，分析总结了Q_2黄土蠕变特征和应力—应变等时曲线特征，得出Q_2黄土在不同的应力水平下蠕变变形表现形式不同；在不同的时刻应力—应变等时曲线存在有较明显的拐点，拐点所对应的应力即为屈服应力，屈服应力随着含水量的增大而呈指数形式降低；Q_2黄土可近似看成一种线性粘弹塑性体。

Combining with the National Natural Science Foundation ofChina(No.50478032), following researches were done in this thesis: 1 The variation regularity of the ultimate anti-bending capacity of therectangular-sectioned beam with different corrosion has been obtained through thequalitative analysis of 48 beams (32 corroded beams and 12 comparing beams) withaccelerated corrosion; 2 The conclusion has been obtained that the strain of corroded steel bar andconcrete no longer fit in with the assumption of plane section through the analysis ofthe strain data, the strain relation of steel bar and concrete in the mid-span section ofvariously corroded beams at ultimate has been obtained. Through the building of newgeometric relation, the expression of the height of compressive area in the corrodedbeam with rectangular section has been deduced, and the formula with corrosion rateas the main variable for the anti-bending capacity of the corroded concrete beam hasbeen suggested and verified by experiment.; 3 The influence of steel bar corrosion and the concrete regression to the flexureductility coefficient of the corroded structure component has been analyzed. Based onthe relation of steel bar and concrete at yield and ultimate, the expression for theflexure at yield and ultimate of corroded reinforced concrete beam, and the model forthe calculation of the flexure ductility has been built.

本文结合国家自然科学基金项目(50478032)"既有钢筋混凝土桥梁时变可靠度研究"，主要进行了以下研究工作： 1通过对48根快速锈蚀钢筋混凝土矩形截面梁(32根锈蚀梁和12根对比试验梁)数据的定性分析，得到了不同锈蚀率下，锈蚀钢筋混凝土矩形截面梁极限抗弯承载力的变化规律； 2通过对应变数据的分析，论证了锈蚀构件钢筋和混凝土的应变不再符合平截面假定的结论，并通过回归分析得出了不同锈蚀率的螺纹钢筋梁和光圆钢筋梁在极限弯矩作用下，跨中截面处钢筋应变和钢筋处混凝土应变的关系，通过构造新的几何关系，得出了锈蚀钢筋混凝土矩形截面梁计算受压区高度的表达式，既而得出了以锈蚀率为主要变量的锈蚀钢筋混凝土矩形截面梁的正截面抗弯计算建议公式，并通过试验数据加以验证； 3分析了钢筋锈蚀和混凝土劣化对锈蚀构件曲率延性系数的影响，结合钢筋屈服和极限弯矩两种状态下钢筋和混凝土的应变关系，分别得到了锈蚀钢筋混凝土矩形截面梁屈服曲率和极限曲率的计算表达式；既而推导出曲率延性系数的计算模型。

In the design of expension tool, the cone angle is the key, because it must satisfy the plastic extreme condition of the expension tube and reduce the upgoing frictional resistance of the expension cone to minimize the possibility of tool sticking. It is preferred that the material quality of expension tube must differs from that of casing and the yield limit of expension tube must be less than that of casing, which is favorable to protect casing.

在膨胀工具结构设计中，锥角设计是关键，除了要满足膨胀管达到塑性极限条件外，还应综合考虑膨胀锥上行的摩阻尽可能小，以减小工具卡死的可能；膨胀管的材质应与套管材质有差异为好，并且膨胀管的屈服极限应小于套管的屈服极限，这样有利于保护套管。

In order to evaluate measuring uncertainty of tensile testing result of metallic material, the mathematic model of calculating uncertainty is established and different factors of influencing testing result are determined taking rectangle head shorter proportional sample of 18mm Q235B plate as example.

为评定金属材料拉伸试验的结果测量不确定度，以轧制厚度为 18mm的Q2 3 5B板材矩形带头短比例试样为例，建立了不确定度计算的数学模型，确定了影响试验结果的下屈服力FSL、最大力Fm、试样原始厚度a及试样原始宽度b等各项因素，计算出了各种因素的标准不确定度，得出拉伸试验结果的扩展不确定度，并给出最终测量结果的表达式：下屈服强度ReL、抗拉强度Rm的最终测量结果分别为(3 0 5± 5 )MPa和(4 3 5± 10 )MPa。

Analyzing the relationships among the initial yielding point, significant yielding point, ultimate point and other key point in parameterless pushover curves, considering the seismic design level, the parameterless pushover curves are transformed to general pushover curves. Then the general pushover curves are converted to a spectral capacity curves for building, that is, a plot of spectral acceleration versus spectral displacement, using the simplified nonlinear static analysis method to estimate the seismic vulnerability of multistory brick structure and multistory and high rise reinforced concrete.

分析了无量纲坐标描述的推倒曲线中初始屈服点、明显屈服点及极限点等关键点之间的关系，考虑建筑物地震设防水准，将无量纲坐标描述的推倒曲线还原为以侧力及其位移描述的推倒曲线，进而将其转换为以谱加速度及谱位移表示的承载能力曲线，采用简化结构静力非线性分析方法，估计我国多层砖房及缺乏震害经验的多、高层钢筋混凝土框架结构房屋的地震易损性。

For the aged aluminum alloys which generally contain disc/plate-shaped or rod/needle-shaped precipitates, a model has been established, from the viewpoints of thermodynamics, kinetics and strengthening theory, to relate quantitatively the yield strength to the size, volume fraction and aspect ratio of precipitates which all were analytical associated with the chemical compositions of alloys, aging temperature and aging time. This model has been experimentally proved to well predict the variation of yield strength with the evolution of disc/plate-shaped or rod/needle-shaped precipitates for present Al-4. 62wt% Cu-0.65wt% Mg alloy aged at 513K and Al-1. 12wt% Mg0.57wt% Si alloy aged at 463K, respectively, and the yield strengths simulated by this model were also found to be in well agreement with previously measured values for a series of aged Al-Cu binary alloys, AA6061 and Al-Zn-Mg alloys.

以析出热力学、长大动力学及强化理论为基础，研究了含有盘/片状、棒/针状时效析出强化相铝合金在时效过程中时效析出相尺寸、体积分数和长径比等参数的演变及其对合金时效强化效果的影响，给出了合金成分、时效变量与微观组织参数之间非线性的解析表达关系式，进而从微观结构—宏观性能相结合的角度出发建立起了具有盘/片状、棒/针状时效析出相铝合金的时效工艺—屈服强度量化模型，并将该模型应用于不同温度、连续不同时间时效下Al-Cu二元系列合金、6061铝合金和Al-Zn-Mg系列合金的屈服强度预测，得到了与前人实测值吻合良好的结果。

The test results show:(1) Under the action of the EL-centro seismic wave the yield sequence of the structures is the root of shearing wall - end of beams - root of columns, while the shearing wall functions as bearing of the most of anti-seismic action of the structures.

试验结果表明：(1)在EL -centro地震波作用下，结构的屈服顺序为：剪力墙根部—梁的端部—柱的根部，且结构的大部分抗震作用将由剪力墙承担，因此剪力墙的屈服强度对结构的承载能力和变形影响很大。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。