疲劳强度

Median fatigue life is usually used to estimate the fatigue properties of materials while the dispersibility of the data is always ignored.

目前，在评价材料的疲劳强度时，往往只注重比较材料的中值疲劳寿命，而忽略了对数据分散性的比较。

An iteration method is presented and a computer program is developed for eveluating reliable life of machine parts.

人们早期使用的抗疲劳设计方法，都是根据工作应力和疲劳强度的平均值进行设计的。

It established a finite element model of the parts on the intensity theoretical of metal fatigue basis, and carried on the structure of static analysis, dynamic analysis and fatigue analysis, and a lot of finite element method were used, then the distribution of the stress was got.

在金属疲劳强度理论的基础上，建立了该零件的有限元分析模型，对发动机支架的结构进行了静力分析、动力分析以及疲劳分析，应用了较多的有限元分析方法，得到该零件的应力、应变分布状态。

On the other hand, the mill housing works under pulsating load, so the fatigue damage can take place. With Miner formula and the P-S-N curve of the mill housing, fatigue life is predicted through being programmed in FORTRAN language.

另一方面，由于机架是在脉动载荷下工作，有发生疲劳破坏的可能，本文采用修正的Miner法则，结合机架的P-S-N曲线，通过FORTRAN语言编制程序，预测了机架的疲劳强度可靠性寿命。

Connecting of doubler strake is a relatively weak link, fatigue strength of which is largely reduced due to the influence of the weld flaw, weld inside stress and weld surface figure. If the ship is under the alternate load function for a long time in long service, fatigue destruction of connecting may happen, strength of deck plating or bottom plating strengthened may also be influenced.

复板条的对接接头是一个相对薄弱的环节，由于焊缝缺陷、焊接内应力、焊缝表面形状等因素的影响，使得接头的疲劳强度大幅度降低，船舶在营运过程中长期受到交变载荷的作用，就会引起对接接头的疲劳破坏，继而影响到被加强的甲板或船底板。

The results show that the fatigue life of the peened joint is 20～30 times as long as the as-welded joints .Therefore,the improvement of the fatigue strength of welded joints by ultrasonic peening is remarkable.

试验结果表明：超声冲击方法对焊接接头疲劳强度的改善效果十分明显，能够提高疲劳寿命20～30倍以上，极具实用价值。

The contact fatigue strength was measured after the 20CrNi2Mo and 15CrNi6 steel used asdragging gear on quasi high speed locomotive was carburized and quenched as well as peened,com-pared with that of 20CrMnMo steel.The results shown that the contact fatigue strength limits of thesethree types of steel carburized and quenched essentially same,and the contact fatigue strength Iimit hasbeen increased by 5 porcent after peening,and that the failure appoarances of all contact fatiguespecimen were delamination ...

对20CRrNi2Mo、15CrNi6及20CrMnMo渗碳淬火齿轮及15CrNi6渗碳淬火＋喷丸处理齿轮进行了弯曲疲劳试验，介绍了齿轮试件的设计与加工、试验装置与夹具、试验方法及试验数据的统计处理，试验结果表明，20CrNi2Mo和15CrNi6渗碳淬火齿轮在R＝0.99时的σFlim分别为530MPa和375MPa，与20CrMnMo渗碳淬火齿轮相比，弯曲疲劳强度分别提高80％和27％。15CrNi6经渗碳淬火＋喷丸处理齿轮在R＝0.99时的σFlim为490MPa，比未喷丸处理者提高30％。

Gear ; roller ; contact fatigue ; fatigue strength ; ratios

齿轮；滚子；接触疲劳；疲劳强度；比值

And then it uses stress amplitude method to check fatigue strength and estimates fatigue life of the main girders.

在此基础上，应用应力幅法对主梁进行了疲劳强度的计算和疲劳寿命的估算。

And then it uses stress amplitude method to check fatigue strength and estimates fatigue life of the main girders.

应用应力幅法对主梁进行了疲劳强度的计算和疲劳寿命的估算。

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。