疲劳

Some important conclusions were obtained, and a new theory of multiaxial damage fatigue and the life prediction models were presented. First, based on the multiaxial fatigue experimental researches, the characteristic of cyclic stress-strain relation was studied deeply under multiaxial proportional and nonproportional loading.

本文在综述目前国内外多轴疲劳研究成果的优点与不足的基础上，从工程应用角度出发，在试验和理论两个方面深入研究了多轴疲劳损伤与寿命预测问题，得到了一些重要试验结果，在此基础上提出了新的多轴疲劳损伤理论及寿命预测模型。

Third, the stress-strain and damage parameters on multiaxial fatigue damage critical planes were analyzed. A new multiaxial fatigue damage parameter was presented. This parameter can not only describe multiaxial proportional and nonproportional loading, but also uniaxial loading.

第三，对多轴疲劳损伤临界面上的应力应变及损伤参量进行了分析，在此基础上提出了一种新的多轴疲劳损伤控制参量，该参量不仅能够描述多轴比例与非比例加载下的疲劳损伤，而且可以退化成单轴的形式。

The percutaneous pulsive current stimulation of hepatic region in exercise-induced fatigue rats may improve the activity of antioxidant enzymes in liver, promote free radical-scavenging and hepatic glycogen synthesis, delay the occurrence of exercise-induced fatigue, and promote the recovery from exercise-induced fatigue.

脉冲电流经皮刺激运动疲劳大鼠肝区可提高肝脏抗氧化酶的活性，促进机体自由基的消除及肝糖原的合成，具有延缓运动疲劳发生、促进运动疲劳恢复的作用。

Ultra-high strength 23Co 14Ni 12Cr3MoE steel was shot peened and the surface residual stress of shot-peened specimens was determined during rotating bending fatigue by X-ray diffraction method.The surface residual stress decreases greatly in the first 10 cycles and it is steady alter 100 cycles.

工件表面的残余应力，对其疲劳性能具有重要的影响，喷丸强化工艺主要利用的就是在表层产生一定数值大小的残余压应力以提高疲劳抗力，但喷丸残余压应力在疲劳过程中并不是稳定的，在一定外力或/和温度的单独或共同作用下，残余应力可发生松弛['一5]。

The object of the present paper was to study the relationship between corrosion fatigue crack growth rate da/dN and stress intensity factor amplitude ΔK of 07MnNiCrMoVDR steel by corrosion fatigue crack growth rate experiment in H2S solution. This steel is the typical material used in chemistry and oil chemistry equipment in our country. Corrosion fatigue safety assessment method of pressure vessels with defects in service could be explored and investigated.

本文研究通过对我国化工和石油化工装置中的典型材料07MnNiCrMoVDR钢在腐蚀介质H2S水溶液中疲劳裂纹扩展速率的研究，寻找其腐蚀疲劳裂纹扩展速率da/dN和应力强度因子幅值ΔK之间的关系，探索研究在役含缺陷压力容器腐蚀疲劳安全评定技术。

5A kind of stress-relief groove of box thread joint has been developped. Finite Element models of several thread joints have been established by ABAQUS. The Morrow Strain-life Model is used to evaluate the fatigue life of 3 kinds of connections with different stress-relieaf grooves of box. The results show that the fatigue life of box with stress-relief groove developed in the paper is the longest.

为了定量评价几种螺纹接头的疲劳寿命大小，采用Morrow应变周期模型结合有限元分析结果计算3种具有内螺纹应力减轻槽母扣的疲劳寿命，计算结果表明本文设计的内螺纹应力减轻槽能显著延长母扣的疲劳寿命。

With the small test sample to simulate the local stress conditions of the coupler knuckles,the fatigue tests are carried out according to the load spectrums of pulling and pressing programs of the freight car coupler s and their simplified spectrums.

用小试样模拟钩舌局部区域应力状态，分别按货车车钩拉、压程序载荷谱和该谱的简化谱进行疲劳试验，所得的疲劳寿命值与现场车钩运用调查统计值均相符合；同时，对 AAR所推荐的恒幅载荷也进行了试样的疲劳试

Wagon body is a complicated weld structure. While physical wagon can not used to do fatigue test, how to make anti-fatigue design has been discussed in this paper. One coal hopper wagon has been taken as an example to study about anti-fatigue design of the wagon. First of all, based on finite element technique and the theory about how to predict fatigue life of weld structure, the technology route and key technique are given as well, which is based on AAR standard about weld structure wagon fatigue life predicted.

论文认为货车车体是复杂的焊接结构，为了使货车车体焊接结构抗疲劳设计在产品的图纸上就能卓有成效地展开，论文以新型煤炭漏斗车为研究对象，对煤炭漏斗车车体抗疲劳设计开展了一系列研究：首先，基于有限元算法和焊接结构寿命预测的疲劳理论，给出了基于北美铁路协会AAR标准的货车车体焊接结构寿命预测的技术路线及关键技术。

In order to improve the life of cement concrete bridge deck pavement,compound beam test was used to research the fatigue characteristics of hot mixed asphalt courses on bridge deck,finite element analysis method was employed to make the mechanical response of compound beam accord with that of actual bridge deck under the same load,the fatigue test was done for compound beams with different pavement structures.

为了提高水泥混凝土桥面沥青混凝土铺装的使用寿命，以复合梁试验评价不同的桥面沥青铺装结构的疲劳性能，采用有限元法分析荷载作用下复合梁试件具有与实际梁体一致的应力响应，并采用复合梁疲劳试验测试不同桥面沥青铺装层组合的疲劳寿命。

The characteristics of fatigue cracking, in rib to crossbeam joints, rib to deck plate joints and rib to rib joints, are understood by the analysis of the test results. The regression line and 95% confidence lower limit of △σ-N curves are given for these joints. Their available fatigue strength is suggested for fatigue design.

通过对试验结果的分析，了解了纵肋与横梁连接、纵肋与盖板连接和纵肋与纵肋连接的疲劳开裂特点，给出了这些连接细节△σ—N曲线的回归线和95%置信下限，提出了疲劳设计时可采用的疲劳强度。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了