失效分析

Combining case history with point reliability solution, applied narrow bound method to calculate general failure probability of composite foundation improved by Dry Jet Mixing, appraised system reliability, precede sensitivity analysis with correlation coefficient of main failure modes in system reliability solution.

3结合工程实例，在点可靠度求解的基础上，运用窄界限范围法求解粉喷桩复合地基系统总失效概率，评价其系统可靠性，并对系统可靠度求解中主要失效模式间的相关系数进行了敏感性分析。

Based on the structure reliability analysis and results of structural optimization theory,the performance function and computative method of reliability index of the homogeneous truss structure under certain failure mode were derived and given,respectively.

以结构可靠性分析和结构优化理论成果为基础，推导得到匀质杆件结构在特定失效模式下的功能函数，给出这一特定失效模式下结构可靠度指标的计算方法。

Then, using the derivatives of the two dimensional normal cumulative distribution function with respect to its variables of parameters, the sensitivity measure of the failure probability of the parallel system or the unconditional up-crossing rate of the combined process can be determined.

最后利用经典的时不变可靠性分析方法确定并联系统的失效概率，并利用二维正态分布函数的导数特性确定失效概率的敏度。

The effect of tribology factors on bearing vibration is studied experimentally. AR model and WPT are used to processing the normal arid abnormal signals. The results are as follows:1. The vibration of ball bearings is caused by the tribology action of contact pairs of ball and ring races and has the essential of tribo-dynamics. Any factors affecting the tribology characteristics of contact pairs will affect vibration and noise of bearings consequently.2. Vibration characteristics of bearing keep almostly unchanged with the increasing of axial load expecting the increasing of nature frequencies. When radial load increasing with axial load unchanged, nature frequencies keep unchanged but some new vibration peaks appears in the spectrum.3. Vibration amplitudes are damped and nature frequency are enhanced with sufficient lubrication. Vibration and noise of bearings increase obviously and roar can happen and the contact surfaces scratch slightly under insufficient and unclean lubrication state. Bearing will be disabled in a few minutes without any lubrication.4. Bearing vibration is unstable under low speed. With the speed increasing, the vibration become stable and natural frequencies increase slightly but the amplitudes increase apparently.5. Bearing vibration can be excited only by some harmonics ofwaviness without lubrication and by all harmonics with lubrication based on the theoretical analysis.6. The nature frequencies of ball bearings decrease with the increasing sizes. When international clearance increasing, nature frequencies decrease in radial and increase in axial and angular and the amplitudes increase in radial and decrease in axial and angular. When the number of balls increasing, nature frequencies increase and amplitudes decrease. When the pitch diameter increasing, axial nature frequency increase and others nearly keep no change. When outer race groove curvature radius increasing, nature frequencies increase in radial and decrease in axial and angular and amplitudes keep no change in radial and increase in axial and angular. When inner race groove curvature radius increasing, nature frequencies decrease and amplitudes increase.7. The distortion in amplitude and frequency components of bearing vibration signals picked up by the present probe measurement method is founded and right conclusions cannot be achieved by the signals. When accelerometer is rigidly screwed with steel stud onto a flat outer surface of a ball bearing, vibration signal can be got without distortion and the reliability of research on bearing vibration is assured.8. AR model is suitable for large samples of bearing vibration signals, square root of length of samples can be used as the upper limitation of order determination and the FPE order selection criterion is effective. Many advantages of AR spectrum are founded over the classical based on FFT.9. Time-Frequency analysis is necessary for abnormal noise of ball bearings. WPT overcomes the principle shortcomings of STFT and proved to be a best tool to process the abnormal signals.

理论分析和试验研究表明： 1球轴承振动是钢球—滚道接触副中的各种摩擦学作用引起的，具有摩擦动力学的本质，任何对接触副的摩擦学特性有影响的因素都将对球轴承的振动和噪声特性产生影响； 2中心轴向载荷作用下，载荷增大使球轴承的固有振动频率升高，载荷越大同样的载荷增幅引起的频率升幅减小，足够大的中心轴向载荷作用下载荷的变化对球轴承振动的频率特性不会产生明显的影响； 3轴向和径向联合载荷作用下，径向载荷不大时球轴承振动的固有频率基本不变，但是可能引起变刚度激励的非线性振动，出现新的频峰，过大的径向载荷将使部分钢球脱离接触，使球轴承的振动和噪声呈现不稳定状态； 4润滑对球轴承的振动和噪声特性有重要的影响，良好的润滑对振动有明显的抑制作用，润滑不充分时，振动和噪声的水平会有明显增高，一定条件下还会激发接触副中的谐振，发出啸声，造成接触表面的伤害，无润滑干接触时，短时的运转就会损伤接触副表面，使振动和噪声迅速增大，并随时可能引发严重的磨损和卡滞失效；接触副润滑良好时，油膜的"刚化效应"使球轴承振动的固有频率有所提高，润滑剂中含有弥散性污浊时，振动的幅度总体升高，但弥散性污浊不会改变球轴承振动的频率特性；浙江大学博士学位论文：球轴承振动的研究 5低速时，球轴承振动的基本特征呈现不稳定状态，随着转速的提高，球轴承振动的频率特性趋于稳定，固有频率频峰升高； 6理论分析表明，干接触时钢球和滚道表面波纹度的某些谐波分量能激励球轴承的振动，振动的幅值与谐波幅值成正比，实际球轴承中钢球的分布不可能完全均匀，波纹度的激励作用会随时发生；润滑接触的分析表明，波纹度的任意谐波分量均能激励球轴承的振动； 7球轴承的几何和结构参数分析表明，球轴承尺寸越大，径向、轴向和角振动的固有频率越低；钢球中心圆直径增大，球轴承的径向和轴向振动的固有频率基本不变，角振动的固有频率有所上升，振动的幅频特性基本不变；径向游隙加大使球轴承的径向振动固有频率降低，轴向和角振动的固有频率有所升高，径向振动幅频特性的幅值升高，而轴向和角向降低；钢球的数量增多使球轴承振动的固有频率上升，幅频特性的幅值下降，径向振动的幅值下降最为明显；外圈沟曲率半径系数增大使球轴承径向振动的固有频率升高，轴向和角振动的固有频率降低，径向幅频特性基本不变，轴向和角向幅频特性幅值升高；内圈沟曲率半径系数增大使径向、轴向和角振动固有频率均下降，振动幅频特性的幅值均有升高； 8试验对比表明，传感器采用探针式安装时，由于探针接触副接触特性的影响，钡(量得到的球轴承振动信号有失真，采用专门设计和制作的试验球轴承，以固定式安装加速度计，首次测量得到了球轴承振动的真实信号，通过对振动信号的分析，验证了球轴承振动的理论模型； 9)基于时间序列分析的AR模型适用于大样本球轴承振动信号的分析，以样本长度的均方根值作定阶上界，FPE做判阶准则，给出的AR谱光滑，频率分辨率高，是球轴承振动分析的简便而可靠的手段； 10以时频域分析的小波包变换分析球轴承异音信号能够比较好地定位和聚焦异音发生的时间，时间间隔，频率范围，同样是球轴承振动分析的可靠的手段，可用作球轴承故障诊断技术。

Through the analysis for feed material bought and drawn of several kinds of possible flaws such as impunity,decarbonization,surface defect, abnormal structure that result in the premature invalidation of spring in serve were put forward in this paper.

提出了几种可能导致弹簧在使用过程中发生过早失效的缺陷，例如：夹杂、脱碳、表面缺陷、异常组织等，并对这些缺陷的形成原因和对弹簧失效的影响作了分析

The fault tree of atmospheric-vacuum distillation unit is established with deductive method on the theory of fault tree analysis.

根据故障树分析理论，用演绎法建立了常减压装置的失效故障树，通过定性分析找到影响稠油加工常减压装置安全性的主要因素，通过定量分析计算出引起失效的各事件的概率和重要度。

In this paper the conception of remanufacturing machining is described, and analyze qualification for worn parts remanufacturing machining, then classify the remanufacturing machining methods, finally discuss the remanufacturing features of some mechanical machining methods, such as restore dimension method, rabbet part method, part replacing method, conversion and plasticity distortion method.

本文叙述了再制造加工的概念，分析了失效零件进行再制造加工的条件，并对再制造加工技术方法进行了分类；重点分析了失效零件机械加工法再制造的特点，并探讨了常用的修理尺寸法、钳工再制造恢复法、镶加零件法、局部更换法、换位法和塑性变形法等再制造修复方法。

The result from the two methods, it is very close and good for the bridge. We also do correlation to the stochastic variable with the stress of the failure models.

同时采用数理统计的方法，分别随机变量和失效模式所对应的应力值进行相关性分析，分析随机变量对失效模式的应力值的敏感性。

According to specific character of research object, via much study work, analyzing many cases of non-heat pressure vessel invalid and combining test result in electric power industry .It analyse and summarize the main reason of hydrogen pressure vessel of electric power plant.This essay carry out crazing performance test of hydrogen causing material .

根据研究对象的具体特点，通过大量的调研工作，分析了大量有关非热力压力容器失效的案例，结合电力行业内已有的检验结果，对电站氢气压力容器失效的主要原因进行了分析和总结；进行了氢致材料开裂性能实验。

In the paper the author relates systematically the research fruits in the program of Research on Sand Slurry Abrasion Mechanisms of Dredging Conditions and New Wear-Resistant Materials. The main contents and innovations are listed as follows.Summarized and analyzed are the wear researches and developments, and the methods of increasing materials wear-resistance. From the viewpoint of the characteristics of two-phase liquid sand slurry wear, combined with the examination and study on easily damaged workpieces, the wear failures basic rules are pointed out, of the pump shell and the cutter-piece on service, and the general principles of material wear-resistant designs put forward. The sand slurry abrasion tester has been designed and developed which can simulate general dredging conditions. Summarized and presented are the position-exchange measuring method of sand slurry abrasion test and the experiment specification of sand slurry wear test of dredging conditions.

文中系统论述了作者在疏浚工况泥沙磨损机理及其耐磨新材料课题研究中的工作成果，主要研究内容和创新点如下：总结分析了磨损研究动态和提高材料耐磨性的方法；从两相流泥沙磨损的特点出发，结合对失效易损件的考察研究，分析指出了现役泥泵壳和绞刀片磨损失效的基本规律，提出了材料耐磨损设计的基本思想；设计研制了能模拟疏浚工况的泥沙磨损试验机，总结提出了泥沙磨损试验换位测试法和疏浚工况泥沙磨损试验规范。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。