裂纹

Some typical torsion problems of isotropic or anisotropic bar with different sections, involving a straight, kinked or curvilinear crack are calculated. The numerical results demonstrate the validity and applicability of the present boundary element method.

分别对含有圆弧裂纹，曲折裂纹及直线裂纹的各向同性材料和各向异性材料柱体的典型问题进行了数值计算，所得结果证明了本文边界元方法的正确性和有效性。

The damage and failure modes of brittle materials under tension and compression are different. The self-similar growth of open microcracks under tension, the frictional sliding, mode-n self-similar growth and kinking of closed microcracks under compression and their influences on the mechanical properties of materials are studied in detail.

在拉伸和压缩情况下微裂纹损伤机制和材料破坏模式都不相同，本文对张开微裂纹的自相似扩展和闭合微裂纹的摩擦滑移、自相似扩展、弯折扩展进行了详细的研究，分别给出了它们对材料的宏观力学性质的影响。

The fifth chapter gets the disturbing characteristic of the flaw by analysis the material characteristic. It analysis and calculates disturbing characteristic of the length of the limiting flaw with the special mathematics mode, and it notarizes the flaw life with the COD way on the basis of analysision of magnitude of the stress.

本文第五章通过对材料属性的分析，得出裂尖启裂因子的分布特性，通过特定的随机数学模型，分析计算并导出了临界裂纹长度的分布特性，并在对应力幅的分析基础上，运用COD方法来确定裂纹扩展寿命，最终运用Monte-Carlo模型计算得到了裂纹扩展寿命的分布特性。

During SCC of type 310 austenitic stainless steel in MgCl〓 solution at 115℃, corrosion process can enhance dislocation emission, multiplication and motion. Stress corrosion microcrack nucleates in the dislocation free zone or at the tip of the crack when the corrosion-enhanced dislocation emission and motion develop to the critical condition.

本文所得主要结论如下： 1.310不锈钢在沸腾MgCl〓溶液中SCC时，腐蚀过程能促进位错的发射、增殖和运动，当其达到临界条件时，SCC微裂纹就会在无位错区中不连续形核或从原裂纹顶端连续形核；由于介质的作用，纳米级微裂纹并不钝化成空洞和缺口，而是解理扩展。

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。

But their crack-Up constraint levels are lower than CT specimen. From the result of finite element analysis for pipelines, the fracture failure pressures of pipelines were predicted.

同时，根据带裂纹管道的有限元计算结果，对管道的断裂破坏压力进行了预测，内侧裂纹的断裂破坏压力比外侧裂纹时的稍低。

By means of high speed gas stream compound with coaxial cutting gas for pulsed Nd:YAG laser on cutting of ceramics,the technological parameters affected on the thickness of re cast layer and the exiting of crack in re cast layer were studied.

针对激光切割陶瓷产生的重铸层和裂纹，设计了超音速喷嘴，采用侧吹高速辅助气流与同轴切割气流复合技术，研究了激光加工工艺参数对重铸层及裂纹的影响规律，开发了获得最小重铸层厚度和裂纹长度的高效率激光切割方

The pH value and electrode potential at crack tip are decreased along with crack growth.

当裂纹长度一定时，裂纹内的pH值和金属电极电位都随着裂纹深度的增加而单调降低。

The aims of this study is to clarify the fracture dependenceof brittle material in plane stress state and their difference between biaxial and uniaxial tension,baized on experimental and analyt...

观测直通裂纹的启裂和扩展过程，证明了双向应力对裂纹驱动力有明显影响，讨论了裂纹扩展的应变准则。

As a foundation of measuring the dynamic stress intensity factor, the influences of geometry and size of the caustics due to the crack propagation velocity are analyzed in detail.

特别分析了裂纹扩展速度对焦散斑和初始曲线的形状、大小的影响，为测量扩展裂纹尖端的动态应力强度因子K_1~d提供了依据，并通过拟合得到了以裂纹扩展速度为参量的修正因子表达式。

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。