疲劳曲线

A technique for dealing with confidence limit-reliability-stress curves of up-and-down test was presented to obtain a more accurate endurance limit.

为获得安全可靠的疲劳极限，提出了处理升降法试验数据置信限－可靠度－应力曲线方法。

In this paper the curvature decision method to determine the turning points of fatigue crack growth rate curve has been proposed.

本文提出了确定疲劳裂纹扩展速率曲线转折点的数学方法——曲率判定法。

Adopting the method in this dissertation to obtain S-N curve can reduce fatigue experiments and helpful in gaining economic efficiency.

采用本文方法预测S-N曲线可以大量减少疲劳试验，节省人力、物力和时间。

Offshore steel platform; reliability; fatigue test; crack growth curve

海洋平台钢；可靠性；疲劳试验；裂纹扩展曲线

Finally, the service life of the valve was estimated based on the fatigue life curve and an improvement of the valve structure was also presented, it could effectively alleviate the stress concentration and prolong the service life.

依据泵阀疲劳寿命曲线，对泵阀使用寿命进行估算，并提出一种泵阀结构改进的新方案，在一定程度上有效减缓了应力集中，对延长泵阀使用寿命具有重要的实用价值。

Orthogonal polynomial and three parameter exponent function model to treat fatigue crack growth curve.

疲劳裂纹扩展曲线的正交多项式与三参数指数函数拟合法。

In comparison with the traditional approach, this method of drawing fatigue diagrams for constant life by fatigue curve equation of constant life can decrease the amount of fatigue experiments by 60%～70%.

用等寿命曲线方程绘制等寿命图与传统方法相比可减少60％～70％的疲劳试验量。

The approach takes a basis of the local statistical parameters of the logarithms of fatigue lives at the reference load. According to an assumption that the material constants in each relation are concurrently in same probabilistic level, the curves is described by a general form of mean and standard deviation curves of the logarithm of fatigue life, in which four material constants are at most contained.

以参考载荷试验数据的统计参量为基础，按照每个模型中材料常数协同处于相同概率水平原则，将曲线表示为对数疲劳寿命均值和均方差线的广义形式，至多4个材料常数。

Finally, based on the dynamic load chart received by kinetics study on gear transmission system of turbine starter, has a statistic on dynamic load, receives the load spectrum by the method of counting range, then selects S-N curve method and Manson-coffin formula respectively for the fatigue damage calculation and life prediction of the tooth circle.

最后，在对涡轮起动机齿轮传动系统进行动力学分析获得的动载荷历程的基础上，对动载荷进行统计分析，采用幅值计数法获得载荷谱；分别采用S-N曲线法和Manson-Coffin法对涡轮起动机齿圈疲劳寿命进行了预估。

It is found that pure copper is a Masing martial whose cyclic creep can take place during fatigue, and the cycle stressstrain curves is divided into three segments.

纯铜是Masing材料，在疲劳过程中发生循环蠕变，其循环应力应变曲线分为三个阶段。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。