裂纹

For the first time the endplate bolted connection's finite element model with the original crack is set up by the singular element, the fracture problem study is introduced to the finite element analyzing. The J integral value and stress intensity factor of the crack tip are calculated by the ANSYS Parametric Design Language program, and the developing of original crack is judged from the K Rule and J Integral Rule.

第一次通过构造奇异单元来建立带初始裂纹的节点有限元模型，将断裂问题的研究引入到端板螺栓节点的有限元分析中，并通过ANSYS软件中Parametric Design Language编程来计算裂纹尖端的J积分值、应力强度因子，根据断裂力学中的K准则、J积分准则判断初始裂纹是否会重新启裂。

Using the perturbation method and Stroh's formula, a nonideal crack, which is mathematically sharp and the opposing crack faces still have a gap in which a stiffless dielectric fills, the two-field problem is reduced to a standard Riemann-Hilbert problem. The internal electric field distribution is obtained by solving a singular integral equation, and then the full field both inside and outside the crack is obtained and the electro-mechanical intensity factors to the first order of accuracy are given.

采用摄动方法对裂尖理想尖锐而裂纹面又具有一定张开的非理想裂纹进行分析，裂隙内含有无刚度的各向同性电介质，利用Stroh公式，将二域问题化为标准的Riemann-Hilbert问题，裂隙内电场分布通过解一个奇异积分方程获得，从而得到裂纹内外的力电全场分布，进而给出一阶精度下的力电强度因子的表达式。

B Using the basic solutions of single inclusion and single crack, singular integral equations of plane interaction problem of line inclusion and line crack have been deduced. Numerical method is set up. Expresesions of stress intensity factor of both inclusion and crack and interface stress of the inclusion are given.

使用单夹杂和单裂纹的基本解，导出了线夹杂与线裂纹相互作用平面问题的奇异积分方程，并为其建立了数值法，给出了夹杂与裂纹端点的应力强度因子及夹杂两侧界面应力的表达式。

The crack growth rate was decreased with crack extension because of the sliding contact of the crack faces.

随着裂纹的扩展，裂纹扩展速率由于裂纹面的滑移接触而减小。

The surface crack on the medium and heavy plate of high-strength steel, which was newly developed by Jinan Steel, was analyzed systematically. The surface cracks of high-strength steel mainly include smaller slit, starlike crack or resillage.

对济钢新开发的高强钢中厚板出现的表面裂纹进行了系统的分析，高强钢裂纹主要表现为小纵裂、星形或网状裂纹。

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。

By adopting its complex variable solutions, the stress solutions of dislocation in bi-material on the whole plane were worked out, integration of which along the crack line would lead to the basic stress solutions in Cartesian and polar coordinates system of an bi-material incline crack.

应用两相材料中点位错在全平面的复势函数解，导出了两相材料中点位错在全平面的应力场解，进而将该解沿裂纹线积分得到倾斜裂纹的直角坐标及极坐标应力场基本解，同时利用该基本解退化出单根界面裂纹的直角坐标及极坐标应力场基本解。

Through the hypersingular integral equations of 3-d crack perpendicular to the interface given in the preceding, the principles of finite-part integrals and of limit are further made use of to pick the hypersingular integral equations of 3-d crack terminating at the interface On the basis of the equations, starting strictly from 3-d theory of elasticity, stress singularities of intersection-line near the front edge of the 3-d crack terminating at the interface are analyzed by virtue of dominant-part analysis of 2-d hypersingular integrals.

根据前面所得到的与界面垂直的单片裂纹超奇异积分方程，进一步运用有限部积分原理和极限理论，推导出了与界面垂直相抵的三维平片裂纹的超奇异积分方程。在此基础上，严格从三维理论出发，使用二维超奇异积分的主部分析方法，对与界面垂直相抵的三维平片裂纹前沿交线上的应力奇性指数进行了分析。

As a result, the crack propagation rates and threshold stress intensity factors for crack arrest in air and water were obtained, and revealed anisotropy.

结果表明，恒载荷下，压痕裂纹在空气和水中不断扩展， 120 h后趋于稳定，从而就可获得裂纹扩展速率和裂纹止裂的门槛应力强度因子KISCC，它们均显示各向异性。

Creep cracks seem always to initiate at inherent casting pores and slowly propa-gate anisotropically along the (001) planes, perpendecular to axis of stress applied, upto the final fast fracture. Creep cracks can also nucleate at fractured carbides or at in-terfaces between carbides and matrix in the alloys containing more carbon.

结果表明：单晶的蠕变断裂具有明显的晶体学特征，蠕变裂纹总是从已有的铸造的显微疏松处萌生；对于含碳量较高的材料，碳化物及其与基体的界面也是裂纹萌生的有利位置；这些已萌生的裂纹在外加应力轴垂直的(001)面上各向异性地扩展，直到由于承载截面的逐渐减小而导致最终破坏。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。