查询词典 crack a book

The crack and stress-strain of Chinese White Poplar were studied by the box counting method. The results showed that the cracks were obvious fractal and that the value of dimension D was determined to be between 1.2～1.5 by studying the crack propagation in the two dimensions. By comparing the crack propagation over a period of time, we found that the value of D increased as the crack increased.

运用数盒子法对裂纹发育带在二维平面内的分布进行了分形特征研究，发现木材裂纹具有明显的分形规律，分形维数为1.2～1.5；通过比较不同时间段的裂纹发育情况，发现裂纹的分形维数随着裂纹的扩展呈增加的趋势。

The conclusions are: The sonic velocity determined by the material's properties is the upper limit of the crack velocity; Bridging fibers plays a key role in increasing the composite's toughness and stopping the crack's propagation; The semi-infinite crack propagating in infinite region with the fiber bridging traction action is equal to the semi-infinite crack propagating in strip.

结论有：(1)由材料性能决定的音速是裂纹传播速度的上限；(2)桥联纤维在增韧复合材料和组织裂纹扩展中起了关键作用；(3)受桥联纤维力作用的半无限长裂纹在无限域中扩展等效于半无限长裂纹在带域中扩展。

With analysing the the fatigue mechanism, the general mode of interply fatigue damage propagation is denoted by delamination length and crack density. Based on the power-law, the relationship between number of cycles and delamination length and crack density are established. The specimen is modeled as an equivalent six-ply material system. Starting with the analysis of interply stress, the interply shear stress under cyclic loading is calculated by using nonlinear three-demension FEA. According to the stage regularity of fatigue damage propagation, such models as average strain, effective modulus, ratio of delamination length and crack density, experimental relationship between crack density and effective modulus, are proposed by introducing subsection coefficient.

通过对疲劳机理的分析，确定了以脱层长度和裂纹密度表示的层间疲劳损伤演化的一般模式，利用指数法则建立了脱层长度和裂纹密度随疲劳循环周次变化的关系；从层间应力分析入手，以等效六层的材料模型对循环载荷下的层间剪切应力进行了三维非线性有限元分析；根据疲劳损伤扩展的阶段性，引入分段系数，分别建立了平均应变与载荷循环周次的分段线性模拟模型、有效刚度随载荷循环周次的变化关系模型、裂纹密度变化和脱层长度变化关系随载荷循环周次变化的分段线性模型以及疲劳裂纹密度和有效刚度关系的经验模型。

Secondly, considering the complexity and heterogeneity of rock-like materials, two new models, namely the Inner Open Sliding Crack Model and the Single Wing Crack Model , are proposed. The two new models and the well-known Sliding Crack Model are consolidated as Zigzag Crack Model in this dissertation.

第二，针对岩石类材料的复杂性和非均质性提出两种新的模型：内张型滑动裂纹模型和单翼滑动裂纹模型，并将这两种模型和经典滑动裂纹统一为锯齿形裂纹模型。

The experimental result shows that when the discharge time was more than 1.5μs, small crack emerged in the fuses due to mechanical force on the heated fuse, and the metallized layer would be evaporated as the crack became long enough to generate disruptive discharge. When the discharge time was less than 150ns, small crack emerged in the fuses due to the current heat, and the metallized layer would be evaporated as the crack became long enough to generate disruptive discharge.

实验结果表明：当熔丝的通流时间大于1.5 ms时，电流热效应产生的机械力使安全膜熔丝的金属层产生微小裂纹，当裂纹达到一定长度，两端发生击穿放电，金属层因蒸发而断开；当熔丝中通过较大的电流时，短时间内(50 ns)的电流热效应使熔丝金属层发生熔化产生裂纹，裂纹两端发生击穿放电，金属层因蒸发而断开。

The results of conversion show that the serious disc must be rejected because its reliable L-HCCF life is greatly less than an overhaul period. Finally, the load distribution of centrifugal and vibration force on labe is derived. Using two method, load on the crack labe gradually reducing and keeping constant with the crack propagation, a crack propagation analysis of fir-tree slot is carried out, and the calculating L-HCCF crack propagation life of slot on the unload method, which is nearly 3 times longer than that on constant method, is 20 times shorter than the pure low cycle life, and agree well with the experimental's.

最后，分析了离心力载荷和振动载荷在榫齿上的分布，进行了榫槽榫齿的有限元计算；提出了枞树型榫槽的卸载概念，并按带裂纹榫齿上的承载随裂纹增长而逐步减少和始终保持不变两种处理方法，进行了复合疲劳裂纹扩展及其寿命计算，由计算得出卸载下复合疲劳裂纹扩展寿命较单纯低周疲劳寿命下降二十多倍；按卸载处理的疲劳裂纹扩展寿命是按恒载处理的三倍多，前者与试验吻合，而后者则偏差较大。

This paper mainly study on the algorithm of the evaluation and recognition of the highway asphaltum pavement crack, and mainly concentrate on the crack image processing and the recognition of the crack type.

本文主要是对公路路面裂缝的识别与检测算法进行原理性的研究，主要集中于裂缝图像的处理以及裂缝类型的识别两个方面。

Utilizing the tools of conformal mapping and Cauchy integral formula and so on, the SIFs at the crack tips are obtained, which can be reduced to the known results under the condition of limitation; For the third and the fourth section, the problems of arc crack and parabolic crack are researched in one dimensional hexagonal QCs.

第二节研究了一维六方准晶狭长体中双半无限共线裂纹问题，利用保角变换以及Cauchy积分公式等工具求得了裂尖处的应力强度因子，在极限的情况下可以还原为若干已有的结果。

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。

And the keytechniques are in the following:(1) The algorithm and program of intensified node arrangement near crack tip andalong crack line (2) The shape function calculation of point near crack based on visibility criteria (3) The contour integral method for calculation of stress intensify factor K_ⅠK_Ⅱ(4) The rock slope appraisal method using circular method, polygonal method orgraph theory method depending on the slope joints combination

程序实现的关键技术和算法如下：(1)沿裂隙结点布置及裂尖结点加密的算法及程序(2)采用可视准则的形函数算计算程序(3)围线积分计算复合型裂纹裂尖强度因子K_Ⅰ、K_Ⅱ的算法及程序(4)圆弧搜索法、折线搜索法和无网格—图论搜索法的算法及程序

"Bird Man's Diary, Butting on the Love Island", Changsha, China

2008年"鸟人日记，顶在爱情岛"，中国长沙

As long as they were in the service of a family of wizards, their magic would remain dormant.

只要他们一天为家庭服务，他们的法力就潜藏不动。