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According to the concept of strain energy of cracked materials, the orientation tensor of crack was defined. Considering the crack-closing and friction between crack surface under compression, The damage tensor, damage strain and effective elastic modulus were formulated. A method for discrete description of damage mechanism was given, and the evolution equation of discrete orientation density of crack was obtained. The relationship of micromechanism and the macro-representation of concrete failure were studied.

从含裂纹材料的变形能出发，引出了裂纹的方位张量；在考虑裂纹受压闭合与滑动摩擦的基础上，给出了损伤张量、损伤应变和有效弹性系数的表达式，在损伤机构离散化方法的基础上，给出了方位密度的演化方程；将上述损伤理论应用于混凝土的损伤分析，研究了混凝土破坏的微观机制与宏观表现的关系及Griffith准则和Mohr-Coulomb准则的相似性问题，对修正的Griffith准则进行了改进。

The corrosion fatigue crack growth and near-threshold characteristcsof high tensile steel HT60 were investigated by using the compact specimens underexposure to synthetic sea water. The da/dN vs △K_ relation in air may be conser-vetivel estimated for that in sea water. In the high △K region with high stressratio, owing to the acceleration of crack growth promoted by stress-induced dissol-ution, the crack opening stress intensity factor K_ represents only the result ofcrack surface in contact with corrosion products, so as to give an overestimation ofK_ at crack tip.

对高拉力钢HT60的腐蚀疲劳裂纹扩展特性和门槛值区域特性，采用紧凑拉伸试件在人工海水中进行了实验和研究，结果表明：在空气中的da/dN与ΔK_关系可以作为在海水中的da/dN与ΔK关系的一个偏保守的预测；在高应力比的高ΔK区域，由于应力诱起溶解促进了裂纹扩展的加速；该裂纹开口应力强度因子K_仅反映了裂纹表面同腐蚀生成物接触的结果，从而导致了K_在裂纹尖端的偏大的估计结果。

Sepal 5, fu covers with tiles shape is arranged, chang Sucun, corollaceous bell form, funnel form, tall foot butterfly form or earthen jar form, brim ministry is shallow 5 crack or deep 5 crack, rotate when bud or tweezers closes account; Staminal 5, on canister of move unripe Yu Guan, hide inside or appear, pollen bead does not have thorn or aculeate, on ovary, often be a cup of shape or surround for flower disc place of dissension, 1-4 room, every room contains 1-2 bead ovule, style 1-2, post is not cracked or 2 crack, rare 3 crack, or 2-4 is cracked.

萼片5片，覆瓦状排列，常宿存，花冠钟形。漏斗形。高脚蝶形或瓮形，檐部浅5裂或深5裂，芽时旋转或镊合状；雄蕊5枚，着生于冠筒上，内藏或外露，花粉粒无刺或有刺，子房上位，常为杯状或为分裂的花盘所包围，1-4室，每室含1-2粒胚珠，花柱1-2个，柱头不裂或2裂，稀3裂，或2-4裂。

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。

Aiming at irregularity of a real fracture surface or a real crack profile, applying Griffith's criterion and fractal geometry, the real asymptotic expression at the crack tip is developed, and it is discovered that the fractality of the crack reduces the stress singularity at the crack tip.

5针对实际断裂面或裂缝的不规则性，利用Griffith能量平衡原理及分形几何，推导了裂缝尖端实际应力场和位移场的表达式，研究发现，裂缝的分形性减小了裂缝尖端应力的奇异性。

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。

As of Tuesday, Google's results were still censored in China.

截至周二，谷歌的搜索结果仍受中国审查。

In order to make the positive action increase and negative one decrease, the sub-forces of the social factors must be adjusted to form a centripetal force.

在这一过程中，人的主体性发挥是社会有机体健康发展的灵魂。