扭振信号拓扑网络的轧机动态扭矩测量

为解决实际测试中轧机传动系统关键点处动态扭矩不易同时测量的难题,提出一种扭振信号拓扑网络的轧机动态扭矩测量方法。通过把扭振计算的力矩和转角位移看作系统的输入输出信号,依据拓扑思想,建立信号之间的扭振信号拓扑网络模型。把有限实测点的测试数据代入扭振信号拓扑网络模型,可获得传动系统中其它关键点处的扭振参数值。轧机实际现场扭矩测试和数据分析处理结果验证了理论推导的正确性。这为轧机现场监测中不易同时布置传感器且非同轴的关键测点的振动参量获取提供了有效方法。通过编制程序可以实现轧机扭振在线监测和故障分析,从而保证轧机正常平稳运行。     

轧机减速机振动测试与故障分析

针对轧机减速机出现振动大、运行状况异常现象，采取振动测试的方法，对减速机进行了全面的测试。并对振动故障进行了准确的诊断。     

基于AR模型MEM法的轧机扭矩信号分析

本文给出了AR模型MEM法的基本理论,通过实例证明这种方法得到的功率谱出较光滑,并且不需要预先知道信号的频率幅值等信息,适合于不以信号处理为研究方向的科研人员和现场操作人员用来分析轧机信号。     

型钢轧机SWC620接轴故障分析及诊断

对型钢轧机中,国产SWC620十字万向接轴运行中存在的故障进行诊断分析,通过对其进行优化改进,有效地提高国产SWC620接轴使用寿命。     

万向接轴附加动态弯矩下板带轧机垂扭耦合振动特性研究

考虑轧机万向接轴倾角产生附加动态弯矩影响,建立了万向接轴倾角影响下板带轧机垂扭耦合振动模型。采用多尺度法得到该轧机耦合系统的主共振幅频方程;并采用奇异性理论分析了该耦合振动系统的分岔特性,得到了系统的转迁集及不同分岔形态的条件。采用1780轧机实际参数,分析了接轴倾角、轧制力参数、接轴扭转刚度以及外扰力等对轧机垂直和扭转方向主共振幅频特性的影响,为进一步抑制轧机振动提供理论参考。     

信息融合在轧机测试与故障诊断中的应用

通过对轧制不同规格钢板的轧制力、轧制扭矩、转速、压下量、轧制电流及轧机刚度等动态参数的测试,获取了轧制过程的完整信息.本文融合轧制力、轧制扭矩和轧制电流信息,研究该机主传动系统在冲击载荷下的响应特性;研究结果表明该机现行轧制工艺及设备状况存在诸多问题;研究结论对开展轧机多源信息状态监测和故障诊断方法研究有指导意义.     

轧机主传动系统振动问题测试分析

针对南钢2800mm中厚板轧机精轧机主传动系统存在的振动现象,对主传动轴、轴承座和轧辊平衡油缸的振动信号进行测试、小波消噪和处理分析,寻找板形和设备安全的影响因素。结果表明,主传动轴上存在较高能量的频率值,应通过合理控制轧机的转速来防止共振和设备损坏;在0.1~1.5的中频段,轧辊平衡油缸动态刚度减小、动态柔度增加,油缸压力产生剧烈振动,影响板形和设备安全,可通过增加液压缸刚度来解决。     

动态拉伸装置及材料动态力学性能测试

设计了一套拉伸冲击加载装置,配合测试系统,可以对动态拉伸加载下的材料的力学性能进行研究。实测的结果表明该装置是有效的。     

万向接轴附加动态弯矩下板带轧机垂扭耦合振动特性研究EI北大核心CSCD

考虑轧机万向接轴倾角产生附加动态弯矩影响,建立了万向接轴倾角影响下板带轧机垂扭耦合振动模型。采用多尺度法得到该轧机耦合系统的主共振幅频方程;并采用奇异性理论分析了该耦合振动系统的分岔特性,得到了系统的转迁集及不同分岔形态的条件。采用1780轧机实际参数,分析了接轴倾角、轧制力参数、接轴扭转刚度以及外扰力等对轧机垂直和扭转方向主共振幅频特性的影响,为进一步抑制轧机振动提供理论参考。     

Maintenance strategy for tilting table of rolling mill based on reliability considerations

Reliability centred maintenance (RCM) is a new strategic framework for ensuring that any asset continues to perform, as its users want it to perform. RCM is a process used to determine the maintenance requirement of any physical asset in its operating context. RCM process entails asking seven questions about each of the selected assets. It makes use of two documents namely, RCM information worksheet and RCM decision worksheet. RCM decision diagram integrates all the decision processes into a single strategic framework. RCM concept developed by US commercial airlines industry has been successfully implemented by Military, Navy, Nuclear power plants, electric power generation and distribution undertakings and several other sectors. These projects have been carried out in the United Kingdom, The Republic of Ireland, the United States, Hong Kong, Australia, Spain and Singapore. The fact that people has enthusiastically received RCM at all levels and has enabled users to achieve some remarkable successes in all of these countries, suggests that it can be universally employed. Literature review indicates that RCM approach is not conventionally applied in process industries in India. Presently, predictive maintenance (PDM) approach along with conventional preventive maintenance is used in continuous/process industries. This approach if implemented in totality will increase the production cost to a large degree and make the production uneconomical. Similarly breakdown maintenance (BDM) approach cannot be applied in such industries as each breakdown involves huge costs. RCM approach is a compromise between PDM and BDM approach for optimising the cost and ensuring the availability of machine.The RCM approach has been applied to the tilting table system of rolling mill for the research work reported in this paper. In the present study, preventive maintenance tasks suggested for power transmission subsystem, guiding and transportation subsystem and hydraulic subsystem in tilting tables are 14 scheduled on-condition tasks, 10 scheduled on-restoration tasks, seven scheduled discard task. Whereas for 14 failure modes no scheduled maintenance has been proposed. Existing maintenance schedule for tilting tables indicates the maintenance action as and when required. Hence RCM based schedule specifies that additional preventive maintenance tasks need to be executed as compared to none initially. Cost incurred for this can be offset from the savings accrued from reduction in loss of production due to repetitive breakdowns. The methodology of RCM adopted in western industries cannot be applied as it is to Indian industries because of labour oriented nature, partially computerised information systems, non-availability of the information about cost of loss of production due to breakdown and age-reliability pattern of equipment, insufficient maintenance database. These problems can be overcome by development of sound MMIS, formulation of RCM review group and imparting suitable training to acquire the relevant skills in RCM. Thus RCM methodology can be applied to Indian industry for reduction of breakdowns as well as optimisation of preventive maintenance cost. This can further boost up the prospects of Indian industry to offer the products at globally competitive prices.     

轧机主传动系统在双源扰动作用下的动力学特性研究

针对轧制薄规格高强度带钢时引起轧机运行不稳的问题,基于传动系统受到轧制力矩和电磁力矩的共同作用,建立双源作用下的传动系统两自由度等效非线性动力学模型,通过平均法求解得出幅值、相位及非线性阻尼和刚度参数之间的函数关系.引入Morlet复小波变换理论,利用模极大值法提取小波脊线,对工业现场测试所得咬钢冲击信号进行非线性刚度和阻尼参数辨识,仿真结果表明两者拟合误差为2.5%;将辨识参数与实际参数用于双源扰动的非线性动力学研究,理论研究表明可以通过增加阻尼一次、三次项和减小刚度三次项等参数来抑制振动的强度.     

Large scale testing and statistical analysis of dynamic fracture toughness of ductile cast iron

The present paper deals with the experimental determination and statistical analysis of dynamic fracture toughness values of ductile cast iron. K_Id data from 140 mm thick single edge bend specimens of two dynamic fracture toughness test series on ductile cast iron from heavy-walled castings were analysed.At first, the statistical analysis of data at −40 °C was done based on ASME Code Case N-670 using a two-parameter Weibull distribution function. Weibull analyses of three samples covering different pearlite contents (?4%, ?9%, ?20%) were performed and characteristics of the distribution functions as well as two-sided confidence intervals were calculated. The calculated characteristics show that K_Id of ductile cast iron decreases with increasing pearlite content.In a second step, the applicability of the Master curve procedure according to ASTM E 1921 to ductile cast iron materials was investigated and it was formally used for statistical analysis of ductile cast iron dynamic fracture toughness data. Although the Master curve method was originally introduced for static fracture toughness data of ferritic steels, the successful individual analyses performed here support the engineering way taken to apply the method to ductile cast iron materials too. The results of both methods, the Master curve procedure and the ASME Code Case N-670, show acceptable congruity. At the same time, it is concluded from the present study that further investigations and experiments are required to improve precision and for verification before the results could be applied within component safety analyses.     

伪随机信号(m序列)相关辨识的动态测试方法

针对传统动态测试用时较长的问题,提出基于伪随机信号相关辨识的动态测试方法.对比传统仪器设备的动态测试方法,阐述基于伪随机信号(m序列)相关辨识的动态测试方法的整体结构,推导出离散系统脉冲响应估计的递推公式;基于估计的脉冲响应序列,应用Hankel矩阵法获得被测对象的传递函数以及幅频与相频特性.通过将估计的传递函数与实际标准化仪器设备的传递函数进行对比,验证该方法的正确性与精确性,且该方法具有用时少的优点.     

滚动轴承寿命及可靠性试验评定方法研究

对于滚动轴承寿命及可靠性试验,在不进行国家规定的寿命试验时,为节约样品成本与试验成本,一般所选的样本量较小.然而使用方或生产方希望能在样本数量与失效数量均较少的情况下,在一定精度下能定量客观地给出被试轴承的形状参数及可靠度、平均寿命等可靠性指标.为此,利用Bayes方法,依据滚动轴承寿命服从二参数Weibull分布的特点,选用无信息先验分布,根据试验数据,给出被试轴承形状参数与可靠度的点估计及形状参数、可靠度、可靠寿命与平均寿命的区间估计.为小样本少失效条件下滚动轴承可靠性的定量评价提供了有效方法.     

基于ANSYS的四辊精密轧钢机轧辊的设计分析

通过ANSYS对3T精密轧钢机用不同直径轧辊在轧制同截面轧件轧制过程的有限元分析，揭示了在轧制过程中应力及轧制力随轧辊直径变化的分布规律，对轧辊的改进设计具有指导意义。     

Matlab在机车车辆动力学试验数据处理中的应用

机车车辆动力学试验是对铁路机车车辆的动力学性能进行检验的一项重要试验.试验方案多、信号通道多、数据量大是这种试验的特点.依据采集到的试验数据进行动力学性能指标——平稳性指标的计算和求取各信号的最大值和最大平均值是试验数据处理的主要工作之一.在试验数据处理中将涉及到数据分段、分段FFT、多段频谱求平均以及信号滤波等的处理.运用Matlab语言的矩阵运算功能和强大的数据处理函数包进行试验数据处理,其程序简洁、调试方便,大大提高了工作效率.     

低温阀门冷态试验的动态传热过程模拟与分析

在确定不锈钢在液氮中沸腾换热系数的基础上,结合其在低温下的物性参数,利用有限元分析软件ANSYS对一低温阀门在正常运行和冷态试验状态下的温度场进行模拟与分析。针对冷态试验情况下填料函处出现冻结的问题,提出在阀杆处添加绝热层的方案,继而通过进一步的模拟计算预测了其改进效果。     

影响活性炭纤维动态吸附氙性能的因素

应用正交设计方法研究了活性炭纤维动态吸附氙的性能.主要考察了吸附温度、原料气浓度和原料气流量及空白未知因素对活性炭纤维动态吸附氙平衡吸附量的影响.结果表明：吸附温度、原料气浓度以及原料气流量为影响平衡吸附量的最重要的因素.其中,吸附温度对平衡吸附量的影响最大,其次是原料气的浓度和原料气的流量.