共查询到20条相似文献,搜索用时 109 毫秒
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悬臂梁的物理性能参数尤其是弹性系数对MEMS中微器件的性能有着重要的影响.根据材料的弹性小变形原理,分析了不同加载方式对悬臂梁弹性系数的影响.结果表明:悬臂梁在不同加载方式下,具有不同的弹性系数.其中,当其承受端部、中部集中栽荷时,分别获得最小、最大弹性系数值.为满足不同应用要求,设计合理的加载方式提供了参考. 相似文献
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对变量泵的控制类型及其对应的实现典型结构进行了归纳,对不同变量形式的特性和适用场合进行了分析,并对负载敏感控制、恒功率控制等多种控制方式组合的原理与应用进行了探讨. 相似文献
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介绍了几种起重机用钢丝绳端部的固定方式及设计中应注意的事项,并对其安全性进行了简单的分析,阐明钢丝绳端部的固定方式对安全生产的重要性。 相似文献
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<正>1.计量方式及性能要求稳定土厂拌站的电子计量系统可以采用仪表、工控机和PLC(可编程控制器)3种控制方式。由于现阶段用PLC对模拟量的控制在实际应用中效果不是很理想,所以现在电子动态计量稳定土厂拌设备的控制系统多数采 相似文献
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王海江 《机械工程与自动化》2021,(2):155-156,159
以阳泉华越生产的M G300/700-WD型采煤机为研究对象,针对采煤机双电机主从控制方式存在不同步的问题,首先应用ADAMS对牵引部进行动力学分析,接着采用Simulink创建了双电机协调控制模型.通过对比不同控制系统下双电机转速差变化,得到了交叉耦合控制系统是较优的双电机控制方式. 相似文献
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从虚拟试运行系统和和虚拟培训系统两个方面介绍了虚拟现实技术在国外钢铁工业中的应用。虚拟试运行系统已应用于紧凑式无头连铸连轧产线、电炉设备和薄板坯连铸连轧产线,虚拟培训系统主要应用于高炉、转炉、连铸、热轧和中厚板的生产。通过应用虚拟现实技术,钢铁企业可以节约设备成本,缩短工期,并在试运行、操作和维护阶段测试控制参数,验证控制程序,检查运行状态。 相似文献
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针对莱钢1 500热连轧终轧温度控制精度低的现状,对机架间冷却水控制系统进行了研究与改造。首先对电动调节阀进行重新测试,然后对机架间冷却数学模型和终轧温度控制的实际应用进行了深入的理论研究。在基础自动化控制系统的改造中,增加了分档式反馈控制和前馈控制;同时在过程自动化控制系统中对预设定计算模块进行了优化。经过现场一年多的运行,改造后的系统大大提高了带钢终轧温度的控制精度和带钢成品的质量,具有很好的应用价值。 相似文献
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Unsteady state work-roll temperature distribution during continuous hot slab rolling 总被引:5,自引:0,他引:5
S. Serajzadeh A. Karimi Taheri F. Mucciardi 《International Journal of Mechanical Sciences》2002,44(12):1556-2462
Predicting temperature distributions in the work-rolls during the hot slab rolling process is of great importance to mill designers. This is because the temperature distribution and the dimensional accuracy of the slab being rolled are both dependent on the work-roll temperature. In addition, the life of the roll is also a function of its own temperature distribution. In this paper, the unsteady state heat transfer equations with time dependent boundary conditions are coupled with a two-dimensional finite element method to predict the work-roll temperature distribution during the continuous hot slab rolling process. To achieve an accurate temperature field, the effects of various factors including the thermal relationships of the work-roll and the metal slab, the idling work-roll revolutions, the rolling speed, the slab/roll interfacial heat transfer coefficient, and the magnitude of the thickness reduction of the slab at each deformation pass are taken into account. Comparisons between the predicted and published experimental results are used to illustrate the validity of the mathematical model. 相似文献
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在现代化的热轧板卷生产线上,通常配置有定宽压力机。定宽压力机位于一次除鳞机和R1粗轧机之间,它的作用是在粗轧机轧制前大幅减小板坯宽度,从而根据订单的要求,生产各种宽度规格的热轧板卷。本文分析了某热轧厂的定宽压力机所发生的一次较为罕见的液压系统故障,提供了一条处理液压故障的正确思路。 相似文献
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Thickness control of hot-rolled strips has become an important issue in recent years because of the need for improving the quality of the hot-rolled strip. For this purpose, various thickness control systems such as finishing mill set-up (FSU), automatic gauge control (AGC), and looper control system, have been developed at steel works. Although these systems have greatly improved the quality of the strip thickness, there still exists a small amount of thickness deviation. It is difficult to adequately control by applying conventional thickness control techniques since hot rolling process is a highly nonlinear system in which many process parameters are coupled. In this study, a fuzzy algorithm to calculate the roll speed variations was developed in order to improve the thickness uniformity of hot-rolled strips. Since the strip thickness is mostly affected by the magnitude of roll separating force depending on the roll speed, the strip thickness deviation between the desired and actual thicknesses can be reduced by controlling roll speed. In order to carry out this investigation, slab analysis was carried out to determine the relation between roll separating force and roll speed for various process parameters such as roll speed, reduction ratio, strip entry thickness, and front and back tensions. From the production data, the effective stress-strain rate relations of the materials used in slab analyses were acquired. Based on the analytical results, the relation between roll separating force and roll speed was approximated by a log function. A fuzzy algorithm was developed to determine variations in roll speed according to variations of roll separating force, depending on various ranges of rolling temperature, reduction ratio, front and back tensions, and strip thickness. In addition, simulations to predict roll speed variations for a small amount of thickness deviation were carried out at continuous finishing mills consisting of seven stands and the calculated roll speed variations were found to be reasonable. Thus, the developed fuzzy algorithm might be useful in reducing the thickness deviation in the actual hot rolling mills. 相似文献
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《Journal of Mechanical Working Technology》1983,7(4):367-383
The accuracy of the width of a hot strip is very important for the improvement of yield, both for the steel maker and the steel user. One of the important technical problems concerning width accuracy is securing a final hot strip with uniform width along the whole length. In the top or tail portion of a hot strip, a local contraction of width unavoidably occurs, called “width necking” or simply “necking”. The amount of necking is determined mainly by the conditions of rougher rolling in the hot-strip mill.In this paper, the mechanism of necking, the influence of rolling conditions on the amount of necking and the optimum edger-rolling pass schedule are described. The main conclusions obtained are as follows: (i) Necking originates from the uneven distribution of dog-bone height along the length of a slab and the local steep width reduction in the top portion of the slab after edger rolling, but is lessened by the formation of flare during subsequent flat rolling; (ii) the amount of necking increases with the increase of slab width and edging draft and with decrease of slab thickness; and (iii) for the minimization of the amount of necking, heavy width-drafts in the early rougher-rolling stage are preferable to heavy width-drafts in the later rougher-rolling stage. 相似文献
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多对多板坯倒垛问题的一种邻域搜索算法 总被引:1,自引:0,他引:1
为解决热轧生产计划中出现的板坯倒垛问题,建立了基于轧制位置与库内板坯多对多对应关系的问题模型,提出了一种新的邻域搜索算法。该算法考虑到轧制计划中的板坯规格组在库内垛位中连续堆放的特点,引入了Sequence邻域概念,使算法能够更好地利用问题的特征,并通过两阶段的寻优替换对问题进行求解。实验结果表明了所提模型和算法的可行性和有效性。 相似文献
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莱钢原有的宽带钢生产线粗轧机基础自动化控制系统已不能满足目前带钢产品的质量要求,系统升级势在必行。改造后的系统控制模型在粗轧规格道次间修正计算、轧制模型等方面都有多项技术创新,并开发了多种模型的自学习策略,显著提高了钢坯宽度控制、轧制力预报、辊缝设定等模型的控制精度。 相似文献
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人工神经网络是近年来迅速发展起来的一种新型信息处理手段。简述了热轧生产线的工艺过程和主要设备,分别介绍了神经网络在加热炉、厚度自动控制、层流冷却等热轧生产工艺中的应用。可以看出,神经网络在热轧生产中发挥着重要的作用。 相似文献