应力张量

A second-order symmetric fabric tensor is introduced to the model, such as the stiffness of the contact planes, the hardening parameter, the dilatant/ contractant coefficient are made dependent of the orientation of the contact plane in order to capture the inherent and stress induced anisotropic behavior of clay.

在上述考虑微结构的饱和软粘土的弹塑性本构模型的基础上将考虑组构的各向异性的二阶组构张量引入接触面上的刚度、硬化参数、剪胀系数等参数中，由此反映材料引起的各向异性和应力引起的各向异性。

In the general case, we must remain satisfied with a partial " covariant conservation" of the stress-energy tensor.

一般情况下，对於应力─能量张量只是部分的"协变守恒"，我们必须感到心满意足。

On the basis of these, the author analyze stress-strain model of rock and soil which is under the groundwater effect, the continuity equation of groundwater when the rock and soil is deformed, and the relation between permeability coefficient tensor of rock and soil and stress field, and brings up the mathematical model of stress-seepage coupling fields.

在此基础上，论文阐明了考虑地下水作用的岩土体本构模型、考虑岩土体变形的地下水流动连续方程和岩土体渗透系数张量与应力场的关系，提出了新的应力-渗流耦合场数学模型。

In the paper, the relation between stress and strain of transverse isotropic material and isotropic material is deduced.

用对张量函数求导的方法导出了横观各向同性材料和各向同性材料的应力应变关系式的一般形式。

Three turbulent models used recently have been analyzed. On the basis of turbulent random theory, the k-εtwo equations turbulent model has been modified by nonisotropic hypothesis, to accommodate the nonisotropic property of flow field.

重新推导了雷诺应力表达式，将湍动粘性系数用一个二阶张量形式表示，以适应流场的各向异性性质，并对ε输运方程的生成项做了修正。

The basic theory of finite deformation is also studied in this paper's appendix, and the metric tensor for stress, strain and their equations between different configurations are derived.

本文还在附录中简要系统介绍了前人给出的有限变形基本理论，针对板料成形建立了应力应变度量张量及其相应的转换关系。

To establish the constitutive equation of material, the metric tensor for stress , strain and their transformation equations between different configurations are derived, and basic theory of finite deformation as well as elasto-plastic deformation criterion are studied. By analyzing the applicability of different element models, four-node quadrilateral degenerated Mindlin isoparametric element is adopted because of its good versatility, and the element stiffness matrix is derived. The static implicit elasto-plastic finite element equation for complex skin stretch-forming is put forward based on Updated Langrange formulation.

本文首先系统地阐述了有限变形的相关基本理论，针对板料成形建立了应力应变度量张量及其相应的转换关系；介绍了材料的屈服准则、塑性变形强化规律、塑性流动规律以及加、卸载准则，并在此基础上建立了有限变形各向异性弹塑性本构方程；对板料成形的单元模型进行了分析，针对飞机蒙皮零件特点，采用通用性强的四节点四边形退化Mindlin等参壳单元进行成形模拟，并导出其单元刚度矩阵的具体形式；基于以上研究，以逐级更新Langrange描述的持续虚功率原理为基础，建立了率形式的复杂蒙皮拉形过程静态隐式弹塑性有限元方程。

It depends on the increment of invariants of the stress, and therefore is independent of the rotation of the principal axes of stress.

使用张量函数表示定理，给出了内变量演化方程的一般表达式，它取决于应力不变量的增量，因而与主轴旋转无关。

Then a general expression describing the relation between effective stress coefficient tensor and equivalent connectivity tensor of pore is proposed; and the expression can be applied to isotropic media and also to anisotropic media.

分析了有效应力系数的物理机理及其主要影响因素，在此基础上，提出了等效孔隙连通率的概念，以此表征岩土类孔隙介质的结构和孔隙之间的连通性，建立了有效应力系数张量演化的普适性理论模型。

Reynolds stresses can be expressed into two forms: one is the generally used second order symmetric tensor, the other is, as described in this paper, the tensorial function of its principal axes directions and turbulent kinetic energy distribution coefficients .

雷诺应力可以有两种表达形式：一种是表达成二阶对称张量，另一种如本文所述，表示为主轴方向及湍动能分配系数的张量函数。

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％。