疲劳

It was found that the low cycle fatigue character has close internal relations with the high cycle fatigue character. In the research of high cycle fatigue of concrete, the test means of cyclic loading between the set constant of force or stress has been extensively used. But this kind of test means can't be used in studying the behavior of concrete low cycle fatigue under large strain.

在研究中发现低周疲劳特征与高周疲劳特征有着密切的内在联系，但高周疲劳问题研究中使用的是在设定的力或应力的上下界限之间重复受力的试验方法，这种方法已无法用于混凝土高应变低周疲劳性能的试验研究。

The successfully designed steel ropes with the specialized ground tackle,which is used to connect with experimental machine,together with a set of revised casting technology of steel rope ends that used in labs can be used in relevant researches.In the research the following significant achievements are made:a set of S-N diagrams and their equations,Goodman Smith figures and an empirical f...

设计成功的钢丝绳与试验机联接的专用锚具、优化出的一套试验室条件下的绳头浇铸工艺，可应用于相关研究工作；研究得到的S -N曲线族及其曲线方程、Goodman -Smith图和疲劳强度计算经验公式、钢丝绳的拉伸疲劳性能和疲劳破坏规律、从宏、微观两个方面对钢丝绳疲劳破坏机理进行的初步研究等等，对钢丝绳结构工程设计人员具有一定的参考价值。

The fatigue is analyzed for the SENT specimen of TA6V titanium alloy at different stress ratio and on different stress level by the general finite element analysis software ANSYS. The dangerous fatigue location is predicted by the nodal stress Y-direction of the hemicycle notch for TA6V titanium alloy SENT specimen. Based on the local stress-strain method and the material S-N graph, the nominal stress-strain of the specimen is converted to the local stress-strain of the dangerous location by the elastic and plastic finite element analysis, thus the fatigue life is estimated by Miner fatigue damage accumulation theory and compared with the fatigue test of small crack growth.

借助大型通用有限元分析软件ANSYS对TA6V钛合金SENT试样在不同应力比和不同应力水平下进行疲劳分析，根据SENT试样缺口处的应力状态分布预测疲劳危险部位，采用局部应力应变法，结合材料循环的S-N曲线，通过弹塑性有限元法将构件上的名义应力谱转换成危险部位的局部应力应变谱，从而根据危险部位的局部应力应变历程采用Miner累积损伤理论对构件的疲劳寿命进行估算，并与疲劳小裂纹试验数据进行比较分析。

The fatigue life followed the logarithmic normal distribution or the two-parameter Weibull distribution by the probability regression method.

为研究预腐蚀对疲劳寿命的影响，进行30CrMnS iN i2A和LC4CS试件加速预腐蚀不同时间后的成组随机谱下的疲劳试验，采用概率回归方法对预腐蚀疲劳寿命分布特性进行检验，表明可采用对数正态分布和双参数威布尔分布描述疲劳寿命分布特性。

This article analyzes high cycle and low cycle fatigue of unnotched steel samples on the basis of theoretical analysis to generalize elastic and plastic fatigue damage and get different rules of evolutionary process under different fatigue damages. Meanwhile, it studies and discusses the calculation of damage evolution and determination of some material constants.

本文在理论分析的基础上，对无缺口钢试件的高周疲劳和低周疲劳进行分析，总结出来了弹性疲劳损伤和塑性疲劳损伤，并得出不同疲劳损伤时的损伤演化规律，同时对损伤演化的算法以及一些材料常数的确定进行了研究和讨论。

Test results show 1 the fatigue strength of peened joints under overloading, in spite of lower than the fatigue strength of the non-overloading peened joints, is still greatly higher than the fatigue strength of as-welded joints; 2 In the range of lower stress level and longer life, ultrasonic peening method exhibit better results than TIG dressing; 3 Fatigue strength of the welded joints with defects (such as undercut at the weld toe) can also be improved greatly after peening treatment.

结果表明，超声冲击处理过的焊接接头经过载后疲劳性能有所下降，但与原始焊态相比提高疲劳强度、延长疲劳寿命的效果仍然十分显著；在低中应力水平、中长寿命区域，使用超声冲击法提高焊接接头疲劳强度比TIG熔修法效果更好；超声冲击处理后，含咬边等缺陷的焊接接头，疲劳强度同样有较大的提高。

By measuring the residual stresses of the cylinder of a cement ball mill in four cases,and the fatique crack spreading for the thermal treatment and the un thermal treatment test samples,the results showed that the heat treatment sample reduced the residual stress,enhanced the fatique strength and lowered the crack spreading speed.

对球磨机筒体的4种情况的焊件进行残余应力测试，并对进行热处理和未进行热处理的试件做疲劳试验及疲劳裂纹扩展测试。试验结果表明：经过热处理的试件，残余应力降低，疲劳强度提高，裂纹扩展速率降低，结构抗疲劳性能增强。不过从工程应用角度看，对于板厚为20～25mm的球磨机筒体而言，不进行焊后热处理也能保证足够的疲劳强度

For this reason, test assessment of fatigue property of wire rope winding sheaves, influence of groove material of sheave on fatigue life of wire rope, fatigue failure analysis of wire rope and microstructure of wire rope have been studied by a new type electro hydraulic servo automatic wire rope–sheave synthetic tester, scanning electron microscopy, micro-hardness measurement, imagine processing and so on.

为此，本文采用新型电液伺服式全自动钢丝绳－滑轮综合疲劳试验装置，综合应用扫描电子显微镜、显微硬度测试和图象处理等技术，对绕滑轮工作钢丝绳的疲劳行为特征和损伤机理进行了系统深入的研究，主要包括疲劳性能试验评价、滑轮材质对钢丝绳疲劳寿命影响、钢丝绳疲劳失效分析和钢丝绳显微组织等的研究。

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。

Two types of single-ply materials, polyester cord reinforced rubber composite and rayon cord reinforced rubber composite, are firstly studied. The essential fatigue properties and rules under cyclic loading are obtained The fatigue mechanism was analysed in terms of fatigue life curve. This part of work lays foundation for catching the experiment information, analyzing the experimental results, confirming the influence factors and explaining the experimental phenomena.

作为试验基础，首先对聚酯帘线和人造丝帘线增强的橡胶复合材料单层板的疲劳进行研究，获得了橡胶复合材料在循环载荷下基本的疲劳特性和规律，并结合疲劳寿命图对疲劳损伤机理进行了分析，在试验信息获取、试验结果分析、影响因素确定、试验现象解释等方面为橡胶复合材料的疲劳研究奠定了基础。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了