查询词典 fatigue

During the prior fatigue life, fatigue damage induces a very small stiffness reduction value that always may be neglected. In the final fatigue life, the stiffness reduction evidently minishes following the power function.

在疲劳寿命前期，疲劳损伤对复合材料层板产生的刚度降变化很小，可忽略不计；在疲劳寿命后期，刚度降则按幂函数变化显著减小。

Considering to the fatigue calendar characteristics of materials, the sequence effects of loading spectrum and the mechanical behavior of cyclic hardening/softening of metals, the cumulative fatigue damage is proved to have character of Markov process. Also, the distribution of the cumulative fatigue damage and its critical value is deduced to vary with the pre-exposure calendar time of materials.

考虑载荷次序效应、材料循环硬化/软化效应及材料的大气环境腐蚀老化效应，论证了疲劳累积损伤随机过程的Markov性，及疲劳累积损伤的正态分布特性，同时证明了临界累积损伤的统计特性随日历时间的变化关系，在此基础上建立了一新的全动态疲劳累积损伤统计干涉模型。

It is considered that fatigue crack is early produced on drill pipes, because the vibration load of drilling tools in air drilling is more severe than that in mud drilling. Fatigue cracks easily occur under alternating vibration. Because the current wellhead detecting instruments can not be used to reflect the change of pump pressure produced after drill pipe piercement timely and accurately, effective measures can not be taken in time to prevent the expansion of fatigue cracks. As a result, drill pipe fracture accidents occur.

失效分析表明，钻杆属于早期疲劳断裂，断裂主要原因是在空气钻井过程中钻具受到的震动载荷远大于钻井液钻井过程中的震动载荷，在交变的震动载荷作用下，钻具容易产生疲劳裂纹；由于现有的井口检测仪表不能精确及时反映钻杆刺穿之后产生的泵压变化，无法及时采取预防措施，疲劳裂纹不断扩展，最终导致了钻杆断裂失效。

It is considered that fatigue crack is early produced on drill pipes, because the vibration load of drilling tools in air drilling is more severe than in mud drilling. Fatigue cracks easily occur under alternating vibration. Because the current wellhead detecting instruments can not be used to reflect the change of pump pressure produced after drill pipe piercement timely and accurately, effective measures can not be taken in time to prevent the expansion of fatigue cracks. As a result, drill pipe fracture accidents occur.

失效分析表明，钻杆属于早期疲劳断裂，断裂主要原因是在空气钻井过程中钻具受到的震动载荷远大于钻井液钻井过程中的震动载荷，在交变的震动载荷作用下，钻具容易产生疲劳裂纹；由于现有的井口检测仪表不能精确及时反映钻杆刺穿之后产生的泵压变化，无法及时采取预防措施，疲劳裂纹不断扩展，最终导致了钻杆断裂失效。

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。

In the light of the shortcomings of the traditional method for predicting the fatigue life of coiled tubing, a new method for the reliability analysis of coiled tubing is offered, that is, normalizing the fatigue test data of coiled tubing with different materials and stress states by introducing a compound random variable X=NS2 based on low cycle fatigue curves.

预测连续油管疲劳寿命传统方法是将许多试样在不同应力水平的循环载荷作用下进行试验直至失效，从而作出S－N曲线，供工程参考，这样不仅费用高，且模拟实际应力条件也较困难。为此，根据低周疲劳曲线，通过引入复合随机变量X=NS2，对不同材料和应力水平下的连续油管疲劳实验数据进行了归一化处理。

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。

The fatigue reliability analysis for the 16V240ZJB diesel engine crankshaft inserving DF4B internal-combustion locomotive were carried out in thisdissertation.Firstly,according to the fatigue loads of the crankshaft,the bendstress and torsion stress at danger zone in rated operation modes werecalculated respectively.The stress randomicity of the crankshaft was analyzedrelating operation modes of acceptance,and the probability distribution ofstresses were obtained with statistical analysis.

运用本文所提出的疲劳可靠性分析模型(干涉模型-Miner准则综合法及弯扭复合模型)和经分析简化得到的材料p-S-N曲线和p-Sa-Sm-N曲面，分别按一维、二维疲劳应力及弯扭复合应力三种情况对东风4B型内燃机车16V240ZJB柴油机曲轴进行了疲劳可靠性分析。

Based on the finite element analysis software ABAQUS, the rotary fatigue life of the aluminum ahoy wheel is simulated. The initiation point of the fatigue crack and its maximum stress are obtained.

该文运用有限元分析软件ABAQUS，对某铝合金车轮旋转弯曲疲劳寿命进行了仿真分析，得出易于产生疲劳裂纹的应力集中点及其最大应力值。

We got alerted a couple of times while we were down south that HETs were on the way to bring us back up north because things were going to go hot again, but it was just rumors.

南下的途中我们不只一次得到警告说重型装备运输车将拉着我们重新北上，因为局势正在变得重新紧张起来，但这只是谣传。

It's the one where they find the ghost in the salt mine.

这一集是演他们在盐矿找到鬼