应力

The stress and stability analysis of arch dam and abutment are the main task of traditional arch dam design. Nowadays there are two kinds of analysis method to use. One method is the arch-cantilever load-distribution method, in which the arch dam stress and abutment thrust are calculated, while the stability of abutment is evaluated by rigid body method or other method. The other is FEM method, which evaluates the arch dam stress and stability of abutment at the same time.

作为拱坝常规设计的主要任务—坝身和坝肩的应力和稳定分析，当今大体有两套体系可用：①用拱梁分载法分析坝身应力和坝肩推力，结合刚体法或其他方法进行坝肩稳定审核；②用有限元法对坝身应力和坝肩稳定同时进行审核。

This research method is to use the three-dimensional mapping software to draw the cardiovascular stent of different size first , next is it create their cardiovascular stent boundary conditions and simulation their of support after implantation according to finite element method into the human body to go; Receive different residue pressures and pressure of the repeated blood circulation , greatest stress , meets an emergency and the relation between total deformation amount caused; Being imitated the cardiovascular stent , the position with damage of fatigue life in the blood vessel by its greatest stress value at the same time ; But by the simulation result of the above , can understand that use life of Palmaz-schatz cardiovascular stent has been more than 109 up till now ; At the same time , can know the position where the stress two times concentrates , the right angle position joined in the rib and rib of Palmaz-schatz cardiovascular stent too.

本研究的方法乃是先会使用三维绘图软体画出不同尺寸的血管支架，然后在根据有限元素法去设定其血管支架的边界条件和模拟其植入人体后；受到不同的残留压力与反覆血液流动的压力，所造成的最大应力、应变及总变形量之间的关系；同时在由其最大应力值去模拟血管支架，在血管中的疲劳寿命与疲劳损坏位置；然而由以上的模拟结果，可以了解到目前Palmaz-schatz血管支架之使用寿命为109以上；同时也可以知道二次应力集中的位置，在Palmaz-schatz血管支架之肋和肋连接的直角位置。

The mechanical mechanism of crack formation and crack growth based on partial concentration of stress of the roadbed are discussed. Crack growth is controlled by tensile stress and crack growth angle which is controlled by shear stress.

就路堤应力集中现象来讨论裂纹的形成和扩展力学机理，即裂纹扩展主要受拉应力作用，而裂纹的扩展角受剪应力的控制。

Based upon the experimental results, including threshold values under static loading,the effects of alternating loading and room temperature creep,as well as metallographic observations of the fractography,it is concluded that notwithstanding stress corrosion or corrosion fatigue in aqua ammoniae,or fatigue in air,the cracks always initiate at the site subject to maximum normal stress(θ=-110°)along the notched surface,and then propagate along the maximum shear stress direction from that site(α=-35°).

由门槛值的测量、交变载荷的作用、室温蠕变的影响、断裂过程的金相观察及断口形貌等结果，可以确认；黄铜不论是在氨水中应力腐蚀或腐蚀疲劳，还是在空气中疲劳，裂纹都从Ⅱ型缺口试样的最大正应力处(0=-110°)萌生，并沿该处的最大剪应力方向(α=-35°)扩展。

The stress fields' distribution of the casing, cement, perforation and oil layer and the relationship between thestress of casing and the quantities of sand production were established in the paper.

大量出砂使地层结构承载能力下降，导致套管内外压力变化，在热应力的作用下，引起套管弯曲，使得局部应力集中，从而使出砂层段及周围的套管应力增加。

Measured the basic physical parameters of unsaturated soils in Three Gorges Reservoir area; 2 measured the initial sample matric suction using the unsaturated triaxial testing system, which can be used to evaluate the unsaturated soil strength and stress; 3 the drying and moisture absorption experiments were executed using the Tempe apparatus, and got the Soil-Water Characteristic Curve, permeability coefficients of every stress level were simulated according to the parameters from the SWCC; 4 the unsaturated soil strength tests were carried out using the GDS triaxial testing system, then got the Mohr circle and shear strength parameters; the results from different stress paths were compared; meanwhile, the axial strain-stress ratio-volume strain curve of different matric suction and different radial pressure was got, as well as their relationship; The research, which provided the necessary data and reference for Three Gorges Reservoir area geologic disaster, is the basic component of Three Gorges Reservoir geologic disaster prevention and research, and experimental results will be used directly in the project.

1量测了三峡库区非饱和土的基本物性参数； 2用非饱和土三轴试验仪量测了试样的初始基质吸力，为评估非饱和土的强度和应力水平提供参考； 3用Tempe仪和体积压力板仪进行了非饱和土的干燥和吸湿试验，得到了土-水特征曲线，并根据其参数拟合出各级吸力状态下对应的渗透系数； 4用GDS三轴仪进行了强度试验，得到了Mohr圆和抗剪强度参数；并比较分析了不同应力路径下试验结果；同时得到不同吸力和不同围压下轴向应变-应力比-体应变的关系曲线和其相互关系。该研究是三峡库区地质灾害防治研究工作的基础性工作，其结果将直接应用到工程实际中，为三峡库区地质灾害提供必要的数据和参考。

The study on the stress-strain relationship of coarse-grained soils become important, especially the characteristics of deformation and strength in the static and dynamic load process.

为了适应土工建筑物应力和变形分析的需要，粗粒土的应力～应变关系成为岩土力学研究的重点内容之一，特别是复杂应力状态下的静、动力变形强度特性已成为学术界和工程界十分关心的一个重要课题。

The results show that new residual stress is about 6MPa under air-cooled normalizing; due to chilling effect of surface quenching, the temperature differences between coarse bar and thin bar in stress frame, and between surface and core of the coarse bar are tremendous; in quenching process, the stress of the certain areas in the coarse bar is maximum at 2s, more than 420MPa, the stress frame casting has the bigger possibilities of fracture.

结果表明，正火空冷时新产生的残余热应力约6MPa；淬火时由于表面激冷作用，应力框在粗细杆间及粗杆的表面和芯部都有巨大温差；铸件在淬火的过程中，粗杆的某些部位在2s时等效应力达到最大，超过了420MPa，极有可能导致铸件断裂。

The plastic deformation mechanism of the process is explained. The vector equations of the curved conical surface and the figure of the particle motion for the forming process of the bending tube are presented. The theoretical model of stress and strain fields of the forming process is deduced. The practical forming process of tubes of large diameter demonstrates the validity of the new type of design method of the ox-horned core bar and the computation formula of the length of the raw tube.

本文通过研究弯管成形瞬时应力、应变状态及演化过程，阐明了弯管成形过程受力变形特点及力学原理；提出了一种适合弯管变形分析的新单元及数值方法；建立了弯管成形过程应力、应变场&标准图象&；通过研究弯管成形过程金属流动规律及力学条件，阐明了本工艺塑性变形机理；建立了描述弯管成形过程的曲锥面向量方程及其质点运动学图象；推导了弯管成形过程应力、应变场理论模型；结合大口径弯管生产过程，验证了本文给出的新型牛角芯棒设计方法和管坯长度计算公式的正确性。

The paper analyzed the residual stress in the machine frame of drying part of the high speed paper machine caused by welding, discussed the effect of welding parameters on the residual stress and compared the mechanisms and efficiencies of eliminating the weld stress by heat treatment and aged-vibrating processes.

对高速纸机干燥部机架焊接所产生的残余应力进行了分析，指出了焊接工艺参数对残余应力的影响；分析比较了热处理和振动时效两种工艺方法消除焊接残余应力的机理和效果。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。