Prediction of Rolling Load in Hot Strip Mill byInnovations Feedback Neural Networks

Because the structure of the classical mathematical model of rolling load is simple, even with the self-adapting technology, it is difficult to accommodate the increasing dimensional accuracy. Motivated by this fact, an Innovations Feedback Neural Networks （IFNN） was presented based on the idea of Kalman prediction. The neural networks used the Back Propagation （BP） algorithm and applied it to the prediction of rolling load in hot strip mill. The theoretical results and the off-line simulation show that the prediction capability of IFNN is better than that of normal BP networks, namely, for the prediction of the rolling load in hot strip mill, the prediction precision of IFNN is higher than that of normal BP networks. Finally, a relative complete rolling load prediction system was developed on Windows 2003/XP platform using the OOP programming method and the SQL server2000 database. With this sys- tem, the rolling load of a 1700 strip mill was calculated, and the prediction results obtained correspond well with the field data. It shows that IFNN is valid for rolling load prediction.

Research on Rolling Load Distribution Method based on Data Mining

A new method of establishing rolling load distribution model was developed by online intelligent information-processing technology for plate rolling. The model combines knowledge model and mathematical model with using knowledge discovery in database （KDD） and data mining （DM） as the start. The online maintenance and optimization of the load model are realized. The effectiveness of this new method was testified by offline simulation and online application.

Investigation on Skidding of Rolling Element Bearing in Loaded Zone

Skidding which occurs when rolling element entering into the loaded zone is prone to cause wear and incipient failure to the raceways and rolling elements. This paper presents a dynamic model to investigate the skidding of a rolling element bearing under radial load when the rolling element is entering into the load zone. In this dynamic model, the effects of the contact forces, friction forces on the rolling element-race and rolling element-cage interfaces, gravity, and the centrifugal forces of rolling elements are taken into consideration. The Hertzian contact theory is applied to calculate the non-linear contact forces. The Coulomb friction law is used to calculate the friction forces. The differential equations of rotational motion of the rolling element with regard to its central axis and the central axis of the outer ring are established respectively. The dynamic equations are then solved by using a fourth-order Runge-Kutta algorithm. The skidding characteristics of rolling element at the entry into the loaded zone are exposed, and the effects of the operating parameters on skidding behavior are carefully investigated.

The finite element analysis of articular cartilage fiber-reinforced composite model under rolling load

Articular cartilage is a layer of low-friction,load-bearing soft hydrated tissue covering bone-ends in diarthrosis,which plays an important role in spreading the load,reducing the joint contact stress,joint friction and wear during exercise.The vital mechanical function

Optimal Design of Deforming Regulation for Compact Continuous Rolling Mill with Balanced Load

If the draught of each mill stand is limited by forced bite condition for compact continuous mill,the rolling load difference between one mill stand and another is very big.If deforming regulation of relative load for each mill stand is approximate to the same,the productive capacity of compact continuous mill can be brought into full play,and also the safety running and the smooth rolling of mill can be ensured.

Effect of Load Distribution on Strip Crown in Hot Strip Rolling

In order to establish precision model, a software to calculate the strip crown of four-high hot rolling mill was developedby using affecting function method according to the strip crown calculation theory. The effect of work roll diameter,unit width rolling load, roll bending force, work roll crown, initial strip crown and reduction, etc, on load distributioneffect rate was simulated by using the software. The results show that the load distribution effect rate increaseswith the increase of strip width, work roll diameter, unit width rolling load, roll bending force, work roll crown,initial strip crown and reduction. Based on the simulation results, base value of load distribution effect rate andfitting coefficients of six power polynomial of load distribution effect rate modification coefficient were determinedconsidering all of the above parameters. A simplified mathematical model for calculating load distribution effect ratewas established.

Mechanical Analysis of Dead Load Crown and Structure Parameter of Hydraulic Elastic Bulging Roll

The dead load crown of hydraulic elastic bulging roll was discussed using the theory of elastically supported beam,and the dead load experiment was carried out. The theoretical calculation is consistent with the experimental result. The structure parameters for the thickness of roll sleeve,the length of the oil groove and the crown of roll were discussed. The fundamental principle of determining the parameters was put forward. The theoretical basis of the application of the hydraulic elastic bulging roll was established.

SELF-ALIGNING EVEN LOAD MECHANISM OF MULTI-ROW BEARINGS OF LARGE STRIP ROLLING MILL

The load distribution of multi-row bearings of large strip rolling mill is fully analyzed by 3D contact boundary element method （BEM）. It is found out that bearings are frequently worn out due to serious uneven load on the multi-row rollers. The constraint mechanism of the previous rolling system is found to be unreasonable by theoretical analysis on heavy machinery structure. A mechanism of self-aligning even load for workroll bearing of 2 050 mm hot rolling mill of Baoshan I＆S Co. is developed. This device is manufactured with particular regard to the structure of 2 050 mm hot rolling mill mentioned above. Hence, uneven load on multi-row bearings is greatly relieved and their lives are remarkably prolonged. Meanwhile, theoretical analysis and on-spot tests prove the rationality and validity of the device.

Web Tension Regulation of Multispan Roll-to-Roll System using Integrated Active Dancer and Load Cells for Printed Electronics Applications

The mass production of primed electronics can be achieved by roll-to-roll（R2R） printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of printed devices in limits. The web tension of a R2R system is regulated by the use of integrated load cells and active dancer system for printed electronics applications using decentralized multi-input-single-output（MISO） regularized variable learning rate backpropagation artificial neural networks. The active dancer system is used before printing system to reduce disturbances in the web tension of process span. The classical PID control result in tension spikes with the change in roll diameter of winder and unwinder rolls. The presence of dancer in R2R system shows that improved web tension control in printing span and the web tension can be enhanced from 3.75 N to 4.75 N. The overshoot of system is less than ±2.5 N and steady state error is within ± 1 N where load cells have a signal noise of ±0.7 N. The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.

球轴承刚度斜弹簧计算方法

针对传统轴承刚度计算方法计算过程复杂,计算结果正确性存疑的问题,提出了一种斜弹簧计算方法,以角接触球轴承为例,推导了受联合载荷、高速运转和仅受中心轴向载荷、中低速运转2种极端情形下的轴承刚度计算公式,斜弹簧计算方法整个过程无需微分和矩阵运算,物理意义清晰,正确性能够自证,计算过程简洁,计算精度高。并与虚功原理法、刚度投影法、准静态模型的增量法进行对比,结果表明:与虚功原理法误差较小,进一步证明了斜弹簧计算方法的正确性;与刚度投影法、准静态模型的增量法误差较大,两者所依据的物理基础不实的计算结果正确性存疑。

微涡轮角接触球轴承打滑性能分析

在赫兹接触理论的基础上,通过拟静力学方程对高速旋转,承受联合载荷和角偏斜的微涡轮角接触球轴承进行计算,得到不同轴向预紧力、径向载荷及偏转角下的轴承受力及其打滑情况,并基于Hirano打滑准则得到轴承的打滑临界曲线。结果表明:为了防止球打滑,以较高转速运转的角接触球轴承需要较大的轴向预紧力;当不承受径向载荷且轴向预紧力低于100 N时,轴承在20000~70000 r/min转速内均发生打滑,当径向载荷增至2000 N时,轴承在20000~70000 r/min转速内均不发生打滑;随着转速的增加,轴承所受离心力增加,球与外圈间的接触载荷增加,球与内圈间的接触载荷减小,导致轴承在高速下的打滑加剧;随着轴承力矩载荷或轴向预紧力的增大,偏转角增大;存在角偏斜的情况下,随着轴向预紧力的增大,球受力增大,离径向载荷作用线越近的球受力更明显,球Hirano打滑系数增大,轴承越不易打滑。

The Saw Gin Stand with Adjustable Movement of the Roll Box

The article contains information about saw gin used at cotton processing plants. The influence of the density of the seed roll, which is formed in the roll box of the saw gin, on the load of the saw cylinder drive and on the technological characteristics of the machine is considered. As a result of the research, in order to preserve the quality characteristics of fiber and seeds, the author proposes a gin stand with a system for regulating the position of the roll box.

汽车B柱Rollforming成型的有限元仿真

在汽车车体构件制造中的辊弯成型工艺应用项目研究中,利用大型非线性有限元分析软件MSC.Marc研究了汽车B柱变截面辊弯成型仿真的有限元建模方法,主要包括板料模型和成型辊模型的建立、单元选择、边界条件、各种参数的设置及成型辊的速度加载等内容,然后采用刚性轧辊沿板料长度方向平动的方式对板料成型过程进行仿真模拟,分析了板料在成型初期、成型中期、变截面成型期三个阶段的变形特点及应力应变分布,得出了与实际成型规律相符合的结论,验证了模型的正确性,为辊弯成型FEA研究提供技术支持。

Modeling,Simulation and Experiment of Electro-hydraulic Screw Down Servo System of Seamless Tube Rolling Mill

Electro-hydraulic screw down servo system（HSDS） is widely used in seamless tube rolling mill in western companies.But in Chinese companies,mechanical screw down system（MSDS） is popularly equipped and has a serious disadvantage that the roller would often be locked when it is overloaded.For the purpose of designing the first set of domestic twin-roller,four-cylinder and six-framework electro-hydraulic HSDS of seamless tube rolling mill,an experiment system that can simulate the process of seamless tube rolling is constructed.A digital simulation model of the experiment system is built with AMESim software and validated by comparing the simulation results with experiment results.The sudden load response of the screw piston position is studied with the built model and the experiment system.To improve the HSDS＇s positioning accuracy with large load,a hybrid control scheme of combining load disturbance feedforward compensation（LDFC） method based on servo valve＇s pressure-stroke feature and anti-saturation integral control（ASIC） is proposed.Both results of simulation and experiment indicate that the transient response time of the single-roller HSDS with the proposed scheme decreases from 0.65 s to less than 0.2 s without static error.To improve the system dynamic stiffness and production qualified rate,a flow rate feedforward compensation（FFC） control strategy based on oil compressibility to dynamic position error is proposed.This FFC strategy is validated with experiments in which the transient error caused by sudden load is reduced to less than 25% of that without FFC.By extending the simulation model to HSDS of a twin-roller,four-cylinder rolling mill,analyzing the mill deformation,and applying the LDFC,ASIC and FFC to the HSDS,the dynamic performance and positioning accuracy of compensated multi-roller HSDS at biting moment are predicted.The research results provide a theoretical and experimental basis for the design of HSDS of seamless steel tube rolling mill.

Accu Roll轧管机咬入条件的探讨

根据AccuRoll轧管机空间变形区的特点，分析了其咬入区轧件的受力状况，建立了咬入条件，探讨了喂入角、辗轧角、导盘和芯棒对咬入条件的影响。

Study on the Fuzzy Reliability of the Bearing in Planetary Transmission System for Heavy-Loaded Vehicles

Based on the fuzzy mathematics theory and reliability design methods, the fuzzy reliability of the rolling bearing in the planetary transmission system for heavy-loaded vehicles is analysed. The reliability and the fuzzy life expectancy of bearings in a practical planetary gear box are calculated in detail. The results show that the methods give a reference to the correct assessment of such type of bearing. Some measures to improve the reliability are also

载荷对带式输送机压陷滚动阻力影响的研究

在长距离水平及微倾斜运行过程中,压陷滚动阻力是带式输送机能耗的主要来源。了解压陷滚动阻力的形成机理和影响因素,对减小压陷滚动阻力,提高带式输送机的效率具有重要意义。文中基于三元件Maxwell固体模型对压陷滚动阻力展开了理论分析,借助AnsysWorkbench有限元软件,对不同载荷下的压陷滚动阻力进行了仿真分析,并搭建了一套可以测试压陷滚动阻力的试验台,深入研究了载荷对带式输送机压陷滚动阻力的影响规律。结果表明:随着载荷增加,当载荷值小于某一限定值时,压陷滚动阻力增加的幅度较小,当载荷超过这一限定值时,压陷阻力增加的幅度显著增大;相比低带速,高带速的压陷滚动阻力增加趋势更为明显。

钢包回转台三排滚子回转轴承强度分析及结构尺寸优化研究

钢包回转台是炼钢车间中低速重载工况下工作的重要设备。某企业的钢包回转台在运行过程中出现了回转支承强度不足的问题。为了探究回转支承的破坏原因,采用理论计算和数值仿真的方法开展研究。采用赫兹接触理论对两种工况下的回转支承进行相应的研究。经过仿真验证发现,在偏载工况下,回转支承中部分滚动体的应力超过了滚动体材料的屈服应力,导致了破坏。为改善受力状态,对回转支承结构的尺寸进行了优化选择,以降低应力。

考虑滚动体变径的滚珠丝杠副滚珠载荷计算模型及其仿真研究

滚珠丝杠副是数控机床传动系统的核心部件之一,在外部轴向载荷的作用下,其内部滚珠所承受的接触载荷分布不均,滚珠与滚道之间接触载荷的变化将对滚珠丝杠副的刚度和寿命产生重要影响。目前现有的滚珠与滚道之间的接触载荷分析计算方法基本是将所有滚珠看作相同直径滚动体,承受载荷按照载荷均布来处理,这和实际滚珠承受载荷情况是不一致的。为了改善滚珠丝杠副内滚珠接触载荷的均匀性,在现有滚珠丝杠副载荷模型的基础上,建立了一种考虑各列滚珠直径可以变化的滚珠与滚道接触载荷模型,并通过该模型研究装配直径尺寸变化的滚珠来实现滚珠丝杠副内所有滚珠载荷分布均匀一致,最终达到提高滚珠丝杠副的刚度和寿命的目的。

基于变载工况的海上风电机组主轴轴承刚柔耦合动态响应分析

针对海上风电机组主轴用三排圆柱滚子轴承在恒载工况下的仿真结果存在局限性、片面性的问题,提出了一种变载工况下的仿真分析方法,建立了轴承接触力学模型和柔性体模型并对轴承内圈、外圈、保持架进行了刚柔耦合处理。基于变载工况,分析了刚性模型与刚柔耦合模型的理论速度、仿真速度以及加速度响应,并通过刚柔耦合模型研究了三排圆柱滚子轴承内部不同接触表面的接触力特性,结果表明:刚性模型的自转误差比刚柔耦合模型大3.67~22.6倍,刚柔耦合模型的加速度趋势更加平稳且速度波动更小;近风叶轮毂端的推力滚子受力约是远端推力滚子的1.85倍,保持架的平均受力是远端保持架的1.6倍。