疲劳强度

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。

Firstly, the article expatiates the concept of fuzzy reliability and the relation between random and fuzzy. It presents a list of random-finite element formula that is suitable for the reliability analysis for mechanical rigid frame system. Secondly, it presents two arrangements' reliability analysis methods that fit for component and fabric system. Finally, according to the characteristic of engineering mechanical, the article first brings forward half random-half fuzzy"stress-intensity intermeddle model"for mechanical intensity analysis, and according to Gerber equation for weariness intensity calculation, the article presents fuzzy number's calculating principle and the fuzzy reliability analysis method for engineering structure weariness intensity.

首先阐述了模糊可靠性概念、随机性与模糊性的关系；在导出摄动随机有限元法随机变量的变分原理、随机有限元控制方程和递归方程组基础上，给出了适合于工程机械刚架系统可靠性分析的随机有限元列式；给出了构件和结构体系两个层次的可靠性分析方法；根据工程机械的特点，首次提出机械强度分析的半随机半模糊"应力-强度干涉模型"，并依据疲劳强度计算的Gerber方程，给出了模糊强度的模糊数运算法则及工程结构疲劳强度模糊可靠性分析计算方法，该方法具有简便实用的特点和普遍意义。

In the meantime, a new relation between the coefficient of variation for a normal variate and its sample size is achieved, where the probability to make mistake Ⅱ is considered 5 The probability distribution of fatigue strength at given life under large sample size determined by a new method is found to follow the log-normal distribution and normal distribution, and a new method are developed to estimate the characteristic parameters of probability distribution of fatigue strength from the probability distribution of traditional tensile properties.

根据P-S-N曲线的要求，采用概率统计方法，导出了考虑犯Ⅱ类错误的概率时获取给定精度P-S-N曲线所需的最少子样容量，引入了不同方法获取的P-S-N曲线结果是否趋同的判别标准，得到了P-S-N曲线的寿命求解法和系数求解法获得趋同结果的条件。 5）研究了大子样条件下指定寿命时疲劳强度的概率分布，并提出了根据拉伸性能的分布估算材料疲劳强度概率分布参数的一种方法。

The uncertain parameters of cylindrical spiral spring fatigue strengthen analysis are analyzed and described as interval variables, and an interval analysis model is established, and the non-probabilistic reliability index of cylindrical spiral spring fatigue strengthen is presented.

分析圆柱螺旋弹簧疲劳强度分析中的不确定性，将圆柱螺旋弹簧设计中不确定参数描述为区间变量，建立圆柱螺旋弹簧疲劳强度非概率可靠性分析的区间模型，提出圆柱螺旋弹簧疲劳强度非概率可靠性的指标。

Based on the Peterson type formula and the Topper type formula, two formule of effective stress concentration factor are developed.

本文考虑了材料、受载形式、尺寸、错位量、焊接残余应力以及焊趾根部短裂纹对错位板节点疲劳强度的影响，在Peterson公式和Topper公式的基础上，分别建立了两个估算这类节点疲劳强度的有效应力集中系数的公式。

The results show that wet air reduces both fatigue life and strength with the influence-factor of 0.6059 and 0.8722, respectively. Wet air environment enlarges the dispersivity of fatigue life, therefore using the corrosion-influence-factor obtained by eigenvalue or mean value to predict the fatigue life with high reliability will cause an unconservative conclusion.

结果表明，潮湿空气环境显著降低了2024-T3铝合金的疲劳性能，潮湿空气环境对其疲劳寿命特征值和疲劳强度均值的影响系数分别为0.6059和0.8722；在潮湿空气环境中疲劳寿命的分散性变大，用疲劳寿命的中值或特征值得到的腐蚀影响系数进行可靠度95%的腐蚀环境下的寿命修正，将得到偏危险的结果。

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

The damage analysis of cracked turbine disk in the rocket engine is described. From a series of analyses, the causes of failure were reasoned through calculation and experiments, fatigue analyses which include stimulating vibration test and fatigue strength calculation were emphasized.

针对某火箭发动机涡轮盘在热试车中出现的裂纹故障，进行全面的分析，准确定位故障类型，以试验和计算分析给出合理的故障原因，重点是在疲劳分析方面所做的工作，包括振动模拟试验、疲劳强度计算，并根据疲劳强度分析结果提出改进方案。

In engineering application, especially in the design stage, it is always using the material fatigue property curve and fatigue strength factors, ie.

在工程应用中，特别是在产品设计阶段，通常利用材料的疲劳性能曲线，再考虑零部件的尺寸系数、表面加工系数及应力集中系数等疲劳强度影响因素进行构件疲劳强度设计。

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。