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Based on the fictitious crack model and critical crack tip opening displacement CTODc, the precritical crack propagation length △ac of concrete was determined by means of three point bending beams. According to the calculation value of △ac, the effective fracture toughness KunIc of concrete was evaluated.

本文采用虚拟裂缝模型，将临界裂缝尖端张开位移CTODc作为控制参数，利用三点弯曲梁试件通过迭代求得了混凝土裂缝亚临界扩展量的临界值△ac，据此求得了混凝土起裂断裂韧度KiniIc、等效断裂韧度KunIc值。

In the equation, the unknown parameters are determined by the crack initiation angle, the crack length and the angle between the direction of the maximum principal stress and the crack surface.

采用双曲线翼型裂纹路径和试验中所得翼型裂纹路径进行了对比分析，二者吻合得很好，验证了采用双曲线近似表示真实存在的翼型裂纹模型的正确性。

To the crack in the rail surface, the effect of longitudinal location on the distribution of the elastic-plastic stress and strain in the railhead is calculated. The maximum stress around the crack in the rail surface over the yield stress and the steel around the crack has plastic strain.

对于条纹状钢轨表面缺陷，主要计算了不同横截面位置条纹状钢轨表面缺陷对轨头内弹塑性应力场和应变场的影响，条纹状钢轨表面缺陷的存在使其周围最大等效应力超过了钢轨材料屈服极限，导致该位置钢轨发生了塑性应变。

The shearing stress on an octahedral plane is used as a rarameter to analyse crack -producing problems under mixed mode fracture and the crack producing direction is considered as the direction with mimimal displacement from crack tip to plasticity boundary.

本文采用剪应力强度因子作为断裂的参数，分析复合型断裂问题，认为裂纹扩展方向为塑性区最短距离方向。

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。

To the soft coal, there are once crack density increment and once crack expansion, and the expansion is import to fracture. It is found that the relation between the fractal dimension of crack and the abutment pressure is polynomial expression.

研究表明，裂隙分维和支承压力具有良好的多项式定量关系；同时，通过顶煤压裂试验得出了基于损伤力学的顶煤压裂本构方程，损伤变量的变化验证了裂隙演化规律的正确性。

These work are mainly based on two assumptions: one is called as the Deeg-Pak assumption, i.e., the crack is assumed to be an impermeable slit and thus the electric field inside the crack is equal to be zero; the other is called as the Parton assumption, i.e., a crack is treated as a permeable cut across that both the normal components of electric displacement and the tangential component of electric field are continuous.

裂纹问题：对于压电介质内的裂纹问题，近十年来人们已做了大量的理论分析工作，这些工作主要是基于两种假设：一种称之为 Deeg-Pak 假设，即假设裂纹为电非渗透的，因此裂纹内的电场等于零；另一种称之为 Parton 假设，即假设裂纹为电渗透的，且跨越裂纹上下表面电位移的法向分量和电场的切向分量是连续的。

I'm not an actor. I'm a professor of paleontology.

我不是演员，我是古生物学教授

Spider Network Web site that is a very image of the name.

网络蜘蛛即Web Spider，是一个非常形象的名字。