Predicting Damage Rate of Asphalt Pavement for the Fatigue Performance Cracking with Axial Loading

The damage rate of asphalt pavement for the fatigue performance cracking is studied with axial loading by the relationshi Pof surface cueved index with Falling Weight Deflection basin, bottom pulling strain of asphalt surface and aumbers of axial loading. The predicting result of standard axial loading and more-classified loading is very different, so as its increasing rate with the time going. It fits real circumstance to predict the fatigue character of asphalt pavement according to more-classified loading and could be an effective measurement for predicting fatigue life of asphalt pavement ruder axial loading.     

Finite Element Analysis of Single Pearlitic Colony with Layer Meso-structure

A great number of experiments show that pearlitic steel with Layer Meso-structure depend greatly on its struc- ture. Its fatigue life is marked influenced by the interlamellar spacing. Based on the finite element analysis of single pearlitic colony with different interlamellar spacings, the reason of the interlamellar spacing is investigated, which plays an important role in the mechanics behavior of single pearlitic colony. It is necessary to establish the relationship between the microstructure and the mechanics behavior of the pearlitic material, and the importance of the interlamellar spacing is introduced into the constitutive equation of Single Pearlitic Colony.     

An Analysis of the Scaling Failure of the Nodular Iron Composite Polls

It is recognized that the scaling failure of nodular iron composite rolls in hot rolling is a problem of fatigue brittle fracture. The temperature field,stress,critical crack size as well as the interior quality of the rolls are presented. The theory of fracture mechanics is used to explain the cause of the scaling failure. At the same time, the way to extend the durability of the rolls is also studied.     

Wavelet Analysis of Electrically Evoked Surface Electromyography Signals During Muscle Fatigue

By analysis of electricallyevoked surface electromyogram(SEMG) to suralmuscle, study the characteristics of SEMG signal during muscle fatigue. The time stretchingof two semi-ave of M-wave are analyzed respectively by wavelet method choosing wavelet function matching to M-wave. Indexes of muscle fatigue are educed accordingto the scale of wavelet transform, are the quantitative analysis is realized during muscle fatigue. This method overcomes the limitation of Fourier Transform that it has no resolution in time domain, find indicators of SEMG which are correct, reliable and easy to interpret, and try to providetheoretic referencefor the applicationsof these indicators.     

高速铁路隧道基底软岩动力累积损伤特性

利用相似材料模拟高速铁路隧道基底软岩,采用荷载控制和非对称正弦波循环加载方式对软岩试件进行动三轴疲劳与损伤检测综合试验。通过试验结果分析,建立了软岩3参数多项式疲劳寿命计算模型和4参数多项式累积损伤参量计算模型,获得了软岩疲劳损伤特性,即：软岩疲劳破坏表现为端部拉-剪复合破坏和中部压-剪复合破坏两种模式;疲劳破坏全过程表现为初始微孔隙压密、裂纹发生与稳定扩展以及损伤裂纹加速发展3个发展阶段;软岩疲劳寿命主要取决于本身强度和动应力水平,强度愈高、动力应力水平愈低,其疲劳寿命就越长;当动应力水平相同时,软岩疲劳寿命与其弹性模量呈线性增长关系。     

虚拟仪器技术在疲劳试验机功能改进中的应用研究

为了提高SVF-1E-01型电液伺服拉压疲劳试验机的测试精度、简化试验操作，应用虚拟仪器技术对其进行了改造。采用研祥工控集团的PCL-812pg多功能数据采集接口卡，在WIN98操作系统平台下，用面向对象的可视化编程环境Delphi5.0集成，设计了虚拟示波器及虚拟信号发生(合成)器。改进后的系统功能包括：模拟信号的采集与显示、单一及多路合成信号的产生及输出等。软件系统具有形象、直观、操作方便等特点。试验结果表明：控制信号精度较高，可以满足试验的要求。整个软、硬件系统接入拉压疲劳试验机中，完成该疲劳试验机     

发动机轴瓦抗摩擦疲劳方法的研究

现代发动机比功率的提高,使得发动机的交变载荷明显增加,发动机轴瓦的摩擦损耗导致轴瓦疲劳破坏的问题较为常见,所以轴瓦的润滑状态对其疲劳寿命有很大影响。在传统设计中对此类问题的影响研究较少,本文从理论上对该问题形成的原因以及解决办法进行了探讨。