某钢结构剩余安全使用期限的评估

由P-S-N曲线关系,得出结构剩余安全使用期限的表达式,利用此式对某港口抓取装置进行评估计算,得出其剩余安全使用期限,为以后的使用和维修以及可靠性的研究提供了依据.     

在役油气管道腐蚀剩余寿命预测方法本文得到中国石油天然气集团公司“九*五”重大应用基础研究项目资助

This paper has presented a new method of the remaining life prediction of corroded pipeline based on the reliability theory.This method involves establishing the probability distribution models of variables-corrosion velocity,corrosion flaw size,critical corrosion flaw size.Then,a function of the failure probability or reliability verse the service time of corroded pipeline could be gained by calculation.Utilizing this function,we could determine the remaining life of the corroded pipeline as long as the acceptable probability or target reliability was determined according to risk rank and area grade of the pipeline lying.Decision of the inspection interval of corroded pipeline could be made as result of the remaining life prediction.The new method has been utilized successfully in several pipelines.     

基于未确知信息的复杂结构能度可靠性分析

针对钢结构系统的模糊能度可靠性分析中需要较大数据量的问题,提出了基于未确知数学理论处理载荷分布规律的一种新方法, 即用未确知有理数表示载荷变量来计算变量的特征值。未确知有理数为最常用的离散型未确知数, 可以较为精细地刻画具有不确定性的量, 避免只用单一实数点值来表示这种量时产生的信息遗漏和失真。复杂模糊结构系统的可靠性分析中,对含有多个可能失效模式的大型复杂结构系统进行可靠性计算是个难点。采用结构的能度可靠性模型,用优化准则法选取可能的临界元,用增量载荷法确定主要失效模式的极限状态方程,在确定的截集水平下,确定了系统钢结构可靠性指标。通过未确知数学理论和能度可靠性模型的巧妙结合,解决了上述难点并使计算结果更接近实际真值。为工程复杂结构系统可靠性分析探索一种新型的计算模式和方法。      

基于未确知信息的复杂结构能度可靠性分析

针对钢结构系统的模糊能度可靠性分析中需要较大数据量的问题,提出了基于未确知数学理论处理载荷分布规律的一种新方法, 即用未确知有理数表示载荷变量来计算变量的特征值.未确知有理数为最常用的离散型未确知数, 可以较为精细地刻画具有不确定性的量, 避免只用单一实数点值来表示这种量时产生的信息遗漏和失真.复杂模糊结构系统的可靠性分析中,对含有多个可能失效模式的大型复杂结构系统进行可靠性计算是个难点.采用结构的能度可靠性模型,用优化准则法选取可能的临界元,用增量载荷法确定主要失效模式的极限状态方程,在确定的截集水平下,确定了系统钢结构可靠性指标.通过未确知数学理论和能度可靠性模型的巧妙结合,解决了上述难点并使计算结果更接近实际真值.为工程复杂结构系统可靠性分析探索一种新型的计算模式和方法.     

改进托辊内部结构提高使用寿命

针对机电总厂所生产的托辊使用寿命低的问题，分析了影响托辊寿命的原因，提出了改进托辊内部结构的机理及技术方案。改进后托辊的使用寿命提高了近5000h，降低了皮带机运行成本，提高了原煤生产效率。     

10CrMo910钢的疲劳损伤演变与寿命估算

对在周期加载条件下运行的锅炉、压力容器、压力管道等设备,不可避免地产生低周疲劳的失效。本文从损伤力学基本理论出发,以10CrMo910钢作为研究对象,采用应力幅法测量材料的低周疲劳损伤,提出了低周疲劳各向同性连续损伤模型,在有效应力和应变等价假设基础上建立了低周疲劳损伤演变和寿命估算式。     

基于多通道融合及贝叶斯理论的刀具剩余寿命预测方法

刀具监测及可用剩余寿命(RUL)预测对降本增效及保证加工质量意义重大.针对单一传感器预测精度波动大、数据利用率低、可靠性低等问题,提出一种多通道信号融合及贝叶斯更新的刀具剩余寿命预测方法.通过计算多通道信号所提取特征的时间序列与对应时间矢量的斯皮尔曼等级相关系数对特征时序做单调性排序,取单调性得分高的特征用主成分分析进...     

稀土变质处理改善高锰钢性能

在受强烈冲击的凿削磨损工况下,使用高锰钢材料已一百多年,虽然具有许多优越性,但也存在材料使用前易产生热裂,使用过程中会出现脆 断、崩裂及使用寿命短等缺点。实践证明,用适量的稀土对高锰钢进行变质处理,可以明显减少热裂倾向,全面改善材料综合性能,提高零件使用寿命,结合材料变质前后的性能变化,对其作用机理进行了初步探讨。     

基于可靠性等劣化理论的设备寿命周期预估

为了建立以可靠性为中心维修思想下的机械设备维修体制,在已有可靠性性能劣化模型的基础上,分析了大修周期与可靠性的关系,结合产品使用性能要求,提出一种新的可靠性阶段划分的方法,以科学确定机器的大修周期和报废指标,预估设备功能故障状态出现时间,进行机械设备寿命预测。并在此基础上改进RCM分析技术,用来评价故障结果,应用逻辑决断图选择预防性维修工作类型,最后形成更为有效的预防性维修大纲。与传统的寿命预测方法相比,这种方法对实验数据的依赖性低于传统方法。     

基于贝叶斯理论的结构系统可靠性优化设计

提出一种新的可靠性优化设计方法来解决小样本可靠性优化设计问题。首先用贝叶斯理论进行结构可靠性预测,给出贝叶斯可靠度的概念;然后建立贝叶斯可靠性优化设计的数学模型,提出贝叶斯可靠性优化设计的数值方法。数值算例验证了所提方法的有效性和正确性。     

岸边集装箱起重机剩余寿命分析

以岸边集装箱起重机为研究对象,基于断裂力学理论,利用有限元分析软件ANSYS对其结构进行模拟,参考BS5400疲劳算法,对其进行剩余寿命分析,满足了实际工程的需要.     

利用后续处理提高高速钢刀具的使用寿命

叙述了高速钢刀具在使用前,进行后续处理的工艺;该工艺简单、周期短、成本低廉,经过处理后的成品刀具寿命比处理前可提高两倍以上。     

离子镀提高W4Mo3Cr4VSiN钢制丝锥使用寿命的研究

为提高W4Mo3Cr4VSiN（F205）低合金高速钢丝锥的使用寿命,对该钢进行了1160℃淬火、不同温度下回火热处理,并对较佳工艺回火后的丝锥表面进行离子镀TiN,对其组织和性能进行了研究。结果表明：560℃回火时,F205钢的硬度达到了最大值;丝锥表面离子镀TiN后,获得金黄色TiN涂层,约2．5μm厚时,涂层的显微硬度达到1921HV50,与基体的结合力最高达35N。丝锥的使用寿命提高了2倍。     

Magnetic Measurements of Stressed-Strained States and Remaining Service Lives of Steel Structures in Hoisting Machines and Pressurized Vessels

A technique of magnetic diagnostics has been developed on the base of correlations between physico-mechanical properties of ferromagnetic materials and their coercive force H_c. Examples of practical utilization of the technique in assessing conditions of bridge cranes and oxygen cylinders are given. By solving the inverse problem, it is possible to diagnose the stage of transition to the yield region on the base of measurements of the maximal and average coercive force, which enables one to diagnose the predestruction condition of gas cylinders. Criteria for rejecting gas cylinders based on results of statistical analysis have been established.     

Relating Humidity Cabinet Life of Lubricants to Their Service Life

In the past the results obtained from humidity cabinet corrosion tests have been useful for comparing one protective material with another, but of little value for predicting the protective life of any given material under atmospheric exposure conditions.

A corrosivity factor, arbitrarily developed, has been found invalid. A method has been developed from experimental data by which the humidity cabinet life of a lubricant may be used to predict its protective life on steel when exposed to the atmosphere. This method is expressed mathematically as a function of temperature, humidity, and protective life (time). It is applicable for world-wide use by using local temperature and humidity data for the location under consideration.

The same general equation appears to be applicable for any lubricant. Each lubricant has its own constants, which must be determined from experimental data. The constants for two lubricants have been determined.     

从滚动轴承受力角度探讨轴承寿命

以向心滚动轴承为例,通过对滚动轴承的受力分析,定性定量地阐述了滚动轴承各元件寿命的不一致性,提出了延长滚动轴承整体使用寿命的方法.     

滚动轴承剩余使用寿命预测综述

滚动轴承作为旋转机械的关键零部件,其剩余使用寿命(RUL)预测对生产维修和人身安全具有重要意义。由于滚动轴承复杂多变的工作环境,使得同工况的参考样本少而变工况的参考样本较多,具有不平衡、不完整、无标签及噪声干扰等特性,增加了滚动轴承RUL预测的困难。随着大数据时代的来临和人工智能的发展,滚动轴承RUL预测方法也变得更加丰富。因此,在故障预测与健康管理(PHM)的框架下,对滚动轴承失效模式和故障数据特点进行阐述,对故障特征提取、降维和融合方法以及得到的性能退化指标分别进行了分类和对比分析。结合数据驱动算法,对滚动轴承RUL的预测方法、模型选择和评估标准进行了梳理和对比。最后对滚动轴承RUL预测未来的发展趋势进行了展望。     

Deep Spatiotemporal Convolutional-Neural-Network-Based Remaining Useful Life Estimation of Bearings

The remaining useful life(RUL) estimation of bearings is critical for ensuring the reliability of mechanical systems. Owing to the rapid development of deep learning methods, a multitude of data-driven RUL estimation approaches have been proposed recently. However, the following problems remain in existing methods: 1) Most network models use raw data or statistical features as input, which renders it di cult to extract complex fault-related information hidden in signals; 2) for current observations, the dependence between current states is emphasized, but their complex dependence on previous states is often disregarded; 3) the output of neural networks is directly used as the estimated RUL in most studies, resulting in extremely volatile prediction results that lack robustness. Hence, a novel prognostics approach is proposed based on a time–frequency representation(TFR) subsequence, three-dimensional convolutional neural network(3 DCNN), and Gaussian process regression(GPR). The approach primarily comprises two aspects: construction of a health indicator(HI) using the TFR-subsequence–3 DCNN model, and RUL estimation based on the GPR model. The raw signals of the bearings are converted into TFR-subsequences by continuous wavelet transform and a dislocated overlapping strategy. Subsequently, the 3 DCNN is applied to extract the hidden spatiotemporal features from the TFR-subsequences and construct HIs. Finally, the RUL of the bearings is estimated using the GPR model, which can also define the probability distribution of the potential function and prediction confidence. Experiments on the PRONOSTIA platform demonstrate the superiority of the proposed TFR-subsequence–3 DCNN–GPR approach. The use of degradation-related spatiotemporal features in signals is proposed herein to achieve a highly accurate bearing RUL prediction with uncertainty quantification.     

轧钢冷床余热利用

现代轧钢企业的冷床,余热仍非常高,若将它释放的热量充分利用,如用于企业浴室、更衣室、会议室采暖等,将节能降耗,效益显著。文中就介绍了这样一个实例。     

显著提高高锰钢零件使用寿命的稀土变质处理

阐述用适量的稀土对高锰钢进行变质处理,可明显减少热裂倾向,全面改善材料综合性能,提高零件使用寿命。结合材料变质前后的性能变化,对其作用机理进行了初步探讨。