尖端作用

In order to calculate the crack expansion life in the action of variable amplitude load for the metal bar with V-shaped notch, the formula of bar fracture frequency was obtained theoretically by setting a size of bar fracture region applied in the engineering. Based on it, the mathematic expression of crack expansion life of bar V-shapednotch tip in the action of variable amplitude load was built.

针对金属棒料在变幅载荷作用下需要较精确地获取其V形槽尖端裂纹扩展寿命的问题，通过给定一个工程上能接受的瞬断区尺寸，获得了棒料断裂频率的计算公式，在此基础上，建立了变幅载荷作用下棒料V形槽尖端裂纹扩展寿命的数学表达式。

Special solutions for the ring circular domain with crack surfaces acted on uniform compressive force, linear compressive force and linear shearing force are deduced in polar coordinate employed the eigenfunction expansion technique in the Hamiltonian system of elastic mechanics. Combined with the general solution for the above problems, the analytical solutions for crack tip fields with surfaces acted on the above three kinds of loads are obtained. These solutions offer theoretical basis to construct analytical elements for plastic analysis of crack.

从弹性力学哈密顿体系理论出发，利用平面弹性力学极坐标系下的本征向量展开求解，推导了环形圆形域裂纹边作用有均布压力、线性压力和均布剪切力情况下的特解，从而得到了裂纹表面作用有以上三种荷载情况下的裂纹尖端场的解析解，为进一步构造进行弹塑性裂纹分析的奇异解析元奠定了理论基础。

The constant term and non-singular terms, which are called general T-stress here, play a significant role in determining the stress and strain fields around a crack tip which in turn can affect the calculation of stress intensity factor of the crack.

裂纹尖端的奇异应力场可以表达为Williams级数展开的形式，其中常数项和非奇异项对裂纹尖端的应力应变场有着很大的影响，这些影响反过来作用于裂纹应力强度因子的计算。

In this thesis, the stress intensity factors of top-down cracks caused by loading are calculated using three dimensional finite element model and compared to the results of plane strain model.

本文采用三维有限元模型分析了荷载作用下自上而下裂缝尖端的应力强度因子，并与二维平面应变模型分析的结果进行比较。

Psychological process: May avoid various situationsnonessential harassment (for example in work situation sexualharassment.), the fluorspar octahedron has six acmes, may representjust in time sixth turn.

心理作用：可避免各场合不必要的骚扰，萤石的八面体有六个尖端，正巧可以代表第六轮。

Based on the fracture mechanics approach, the finite element method analyzed a varity of the stress intensity factor at the pavement crack tip when setting fiberglass-polyester paving mat, and the effect of the stress intensity factor in symmetric load and asymmetric load was studied when the asphalt layer modulus, thickness of semi-rigid base, the the depth of the crack, touch condition, interlay modular, etc., changed.

基于断裂力学的方法，采用ANASYS软件模拟沥青路面典型结构，分析了设置聚酯玻纤布夹层后，在正载和偏载作用下，裂缝尖端应力强度因子的变化，研究了沥青层模量、基层厚度及裂缝扩展深度等结构参量及层间接触条件和夹层模量对应力强度因子的影响规律分析结果表明，设置聚酯玻纤布夹层，可以有效防治荷载型反射裂缝的扩展。

By introducing special stress functions, we find solutions of eighth order homogeneous linear equation set with complex functions method and approach of undetermined coefficients, deduce calculation formulas of bi-material elastic constants for two dissimilar orthotropic composite materials. The expressions of stress intensity factors near finite interface crack tip subjected to symmetric loadings are derived. A engineering application numerical example is given.

通过引入特殊的应力函数，采用复变函数方法和待定系数法求解了八阶齐次线性方程组，推出了两种相异正交异性复合材料板的双材料弹性常数的计算公式，得到了受对称载荷作用的界面裂纹尖端应力强度因子的计算公式，给出了一个工程应用算例。

The mixed boundary problem was reduced to a system of singular integral equations by means of Fourier transform.

利用Fourier积分变换技术将混合边值问题转化为一对奇异积分方程，通过数值求解奇异积分方程获得含裂纹功能梯度板条分别在剪切和法向载荷作用下的I型和Ⅱ型应力强度因子，并讨论了材料的非均匀性和裂纹相对尺寸对裂纹尖端应力强度因子的影响。

In calefactive phase,the electro thermal model of hot bridge wire was established,the calefactive time of invariable current fire case and capacitance discharge fire case were both studied.

桥丝式电火工品不仅普遍用于各类通用弹药，而且还作为一种特殊能源的、一次作用的动力源器件广泛用于导弹、核武器等尖端武器中[1]。

The general feature of the plastic deformation is similar in both charging or uncharging hydrogen specimens.

发现：氢的存在并不改变在Ⅰ型或混合型载荷作用下，裂纹尖端的塑性变形特征，即在主裂纹前端，应变呈不对称分布，裂纹尖端Schmid因子决定了条带状局部形变带的轴线方向。

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％。