According to the paper , the reason of influencing the flaw progress has three factors , that is , the magnitude of stress , material and the mode of flaw 分析表明决定裂纹从萌生扩展到临界裂纹(这时裂纹发生失稳扩展)的扩展过程的主要因素有三个：应力幅值大小、材料、裂纹模式。
The fatigue test is based on nominal stress range . at the last , analyzing and estimating the outcome , testified that fatigue intensity is not dominant in the process of designing the wushan yangtze bridge 疲劳试验按设计名义应力幅进行，对试验结果进行分析评价后，证实了巫山长江大桥的节点疲劳不控制设计。
The paper expounds a way to get stress amplitude spectrum of main girders of overhead traveling crane through computer simulation combining virtual prototype technology and computer random simulation 摘要本文将虚拟样机技术与计算机随机模拟方法结合，探讨了通过计算机仿真的方法获得桥式起重机主梁应力幅谱的基本途径。
Finally , theoretical results and the fatigue test data of equal amplitude are combined , which is introduced the conception of " range of hotspot stress " , and the method of fatigue design for grid structure with bolt - sphere joints is obtained in this paper 最后，将本文的理论研究成果与常幅疲劳试验数据相结合，并引入“热点应力幅”的概念，建立了螺栓球节点网架结构的疲劳验算方法。
At the same time , a fatigue damage evolution law based on the theory of cumulative fatigue damage is presented , using the electrical resistance of material . and the electrical resistance change is validated by the whole - bend experiments under different stress ranges 同时通过电阻建立了基于损伤累积理论的疲劳损伤演化规律，对不同应力幅水平下的存弯疲劳实验试样的电阻损伤变量加以实验验证。
Stress concentration measure on the model of boiler drum with two nozzles was executed and the testing results were compared with the asme criterion , experiential value and the value of finite element method respectively . this measurement result provides direction for evaluation of stress amplitude 设计模拟汽包进行应力测试，并与美国asme规范和经验公式计算值、有限元计算结果进行比较，为后续的低周疲劳寿命估算时交变应力幅值的确定提供依据。
The relations between the dummy stress amplitude and fatigue life can be easily developed . and then , the bhw - 35 steel fatigue design curve can be obtained according with asme criterion and bs5500 criterion . compared ~ vith the design curves provided by the asme and bs5500 criterion , the curve got in this paper provides reliable direction for the fatigue design of boiler drum , which used on the altering generating power plant set 将焊缝材料的虚拟应力幅与寿命关系，按照asme和bs5500规范的方法分析得到bhw ? 35钢疲劳设计曲线，并与asme和bs5500规范中的设计曲线进行比较，为我国调峰机组410t / h锅炉汽包疲劳设计提供可靠的实际依据。
In generally , there is specially mode of flaw in the specially place , this phenomenon is caused by the structure of the crane and the running mode of the crane . the characteristic of the material and the length of the limiting flaw aflcct the bearing ability of the crane . and the magnitude of stress affects the extending velocity 一般来讲，港口装卸机械的特定部位有特定的裂纹模式，这主要是由机械设备结构及其运行所决定，而材料则决定了构件所能承受的强度及其承载能力和临界裂纹的长度范围，而应力幅则决定了裂纹的扩展速度。
The forth chapter analysis the stress on the basis of reliability , the result illuminates that the stress obeys the normal disturbing and uniformity disturbing , however quantity of the stress that can affect the flaw extending is not same with the work cycle . so if we want to get the number of the stress that affects the extending life , we should use carefully the statistic tool 本文第四章经过基于可靠性理论的实测载荷谱分析，发现那些能够促使裂纹扩展的应力幅服从正态分布或均匀分布，而且其量上也有一定差异，只有经过仔细分析比较才能获得影响裂纹扩展的正确的应力幅统计数据。
The third chapter analysis the affections which is the most importance affection in the process of flaw extending ignoring the reliability . the result illuminates that the magnitude of the stress is the most importance affection in the process of flaw extending when the material is determined 本文第三章分析了在不考虑分散性的前提下来考虑影响裂纹扩展寿命过程中哪些因素最为主要，分析发现应力幅值相对于材料属性来讲是更主要因素，当材料属性达到一定范围后，应力幅对裂纹扩展起到了决定性作用。
