一种冷连轧机前滑预测的新方法毕业课程设计外文文献翻译、中英文翻译

1 英文文献翻译1.1 英文文献原文题目A new method for prediction of forward slip in the tandem cold rolling millM. Poursina & M. Rahmatipour & H. MirmohamadiAbstract A new method for prediction of forward slip in the tandem cold rolling mill without the velocity meter sensors based on rolling geometry is proposed here. According to this proposed method, an algorithm is developed for online estimation of friction coefficient and strips behavior. Online exertion of friction coefficient and strips behavior in the rollings program results in better control. So, the unsaturated actuators are satisfied and the possibility of strip tearing is decreased. The strips material is st12. The material is considered elastic-plastic, homogenous, and it follows the Ludwicks constitutive equation law. The yield stress of strip and Young modulus are determined by simple tension test on a specimen of strip before rolling. For validation of the developed scheme, two operating samples are considered and the results are compared with the available literature.Key words : Cold rolling .Forward slip .Friction .Constitutive equationNomenclatureP :Rolling forceD :Diameter of work rollR :Radius of work rollW: Width of striph: Thickness of stript: Inter-stand tensionC, n: Constitutive equations constants: Deformed roll radius: Neutral point angleK: Strip deformation resistance: Friction coefficientfs: Forward slip: Flow stressE: StrainR: ReductionL: Length of contactE: Young modulusv: Poison ratio1.IntroductionTandem cold rolling mill control is a complicated process. The objective of this process is to obtain desirable thickness of strips through exact control of rolling force and forward slip. The magnitude of difference between the measured and calculated rolling force and forward slip lead to saturated actuators. Under this circumstances the slightest oscillation in the control system of tandem cold rolling mill, would enhance the possibility of the strip tearing 1. Rolling force and forward slip depend on the different parameters specially the friction coefficient and mechanical behavior of the strip. These parameters vary during rolling process, while in most of the control programs, they are considered constant. For lack of online information of the friction coefficient and constants of constitutive equation, several researchers have presented models based on the inverse method in order to determine online magnitude of friction coefficients and constitutive equation.Table 1 The list of equations, applied in the presented flowchartFig. 1 Rolling geometry and roller pressure distribution along contact arc 7Byon et al. determined the friction coefficient and constants of constitutive equation instantaneously in a reversible cold rolling mill equipped with full sensors in order to measure forward slip by adopting the inverse method 2. Tieu et al. 3, 4 evaluated the friction coefficient and constitutive equation of the strip in a four Table stand cold rolling mill and offered an applicable model for the friction coefficient.Although rolling forces and forward slips in the previous works have been measured directly through load cells and velocity meter sensors, in some strip-manufacturing plants, the velocity meters do not register the strip speed well enough because the existing rolling mill is not in its standard shape or, in some cases, due to variety of reasons, there is no proper location to install the velocity meter sensors. In this type of rolling process lines, the forward slips are not accurately measured and the calculation of rolling process is made according to constant experimental magnitudes of forward slips.This deficiency leads to more errors in the calculation of rolling line process, and the strip tearing will occur while the actuators are saturated and cannot remove these errors.In this study, a new approach is presented based on rolling geometry in order to predict the online magnitudes of forward slips in a tandem cold rolling mill which is not equipped with enough velocity meter sensors or the existing sensors do not respond accurately. Subsequently, through the inverse algorithm, the magnitudes of friction coefficients and constants of constitutive equation of strip are determined instantaneously. For validation of the developed scheme, two samples of a five stand tandem cold rolling mill at Isfahan Mobarakeh Steel Complex (IMSC) are studied. The comparison of the results between developed scheme and the results available in the related literature are in good agreement.Fig. 2 Effect of inter-stand tensions on pressure distribution and neutral point, tf forward tension, tb backward tension2.Mathematical modelHere, the synchronized solutions of the three equations of rolling force, the forward slip, and constitutive equation model are accomplished.The first equation is rolling force model: different rolling force models are suggested to determine the rolling force where the following form is in common: (1)In online calculations, using simple equations are essential to increase the process speed. For this purpose, the Bland-Ford force model, Eq. (2), is selected 5. （2）Where f1 and f2 are the correction functions for tensile stress and friction coefficient, respectively (Table 1). The second equation is forward slip model: it is obtained when the pressure distributions along the contact arc of each side of the neutral point are equal 6. This equation expresses forward slip as a function of friction coefficient and deformation resistance. （3）Where Ki and Ko are the strip deformation resistance at the entry and exit roll gap, respectively.The third equation is material behavior model: in the tandem cold rolling mill, Ludwicks constitutive equation law, Eq. (4), which predicts the strip behavior, is applied in this study. （4）Where is the effective strain and is calculated by Eq. (5) at each stand and is the flow stress. （5）An algorithm for computing the flow stress-strain curve of strip, C and n and friction coefficient, , is presented based on synchronized solution of the abovementioned three equations. The set of the equations is listed below: （6）Fig. 3 Upper bound of forward slip and neutral point placeFig. 4 The flow stress-strain curve of stripFig. 5 Flowchart of the developed algorithmFig. 6 Schematic diagram of the five-stand tandem cold rolling mill (IMSC)Table 2 Experimental data of IMSC (case 1)3.Determination of forward slipThe aim of this study is to determine the magnitudes of forward slips, the fs in the second equation of the above set, in a five-stand industrial rolling process which is not equipped with enough velocity meter sensors. Teslikov et al. determined the pressure distribution along the contact arc of the strip and roller 7. A segment of a strip during rolling is shown in Fig. 1. Parameter x indicates the place of neutral point along the roller and strip contact arc.The relation between the location of the neutral point in rolling zone and forward slip is obtained according to Eq. (7) 8. （7）In Fig. 1, it is observed that the roller pressure at entrance and exit points are equal to the strip deformation resistance and at the neutral point the roller pressure is at its maximum. In this literature, it is observed that the inter-stand tensions have not been considered 7. In rolling process, inter-stand tensions are applied to decrease the rolling pressure.The effect of inter-stand tensions in a rolling stand is illustrated in Fig. 2 with the corresponding curves. By applying backward tension, the required pressure in deforming the strip is decreased constantly from entrance point to neutral point causing a decline in line (a) to form line (b), dotted line, with no change in the gradient. As observed here, the neutral point Na has changed place toward the exit point due to the downward movement of curve a. In case of applying forward tension as illustrated in Fig. 2, the same phenomenon takes place with the exception that the Na changes place toward the entrance Point. Since the thickness of strip is reduced continuously during tandem cold rolling mill, the forward tensions are greater than backward tensions at stands 1 to 4. In these stands, the neutral point moves toward the entrance point leading to a value increase in the forward slip; therefore, the forward slip in the absent of inter stand tensions shows the minimum value of true forward slip and can be calculated by Eq. (8) 8. （8）The details regarding upper bound of forward slip are illustrated in Fig. 3. In order to determine the forward slip, the following steps are defined:1. The place of neutral point along the contact arc with no inter stand tension (xmin) is determined by combination of Eqs. (7) and (8). 2. The actual pressure distribution with no inter stand tension (diagonal lines (a) and (b) ) could be approximated by diagonal line (a) and horizontal line (b) which are determined by the three data (Ki, Ko, and xmin). Consequently, the slope of line (a) has the minimum possible value due to the zero gradient of (b).3. After applying the inter-stand tensions , the lines (a) (b) and (a) (b) drop downward in parallel forming the lines (a) (b ) and (a ) (b), respectively. 4. Because the slope of line (a) is less than that of the line (a), the intersection of lines (a) and (b ) is closer to the entrance point and is calculated as follows: 5. The upper bound of forward slip fsmin is calculated through Eq. (7), where x=xmaxAt the fifth stand which is the last rolling stand , the forward tension is always less than backward tension; therefore, the method discussed above is not applicable in determining forward slip in this stand. After determining the constants of constitutive equation of the strip according to forward slips and rolling forces of the first four stands, Eq. (6), and considering the available strip strain in stand 5, Eq. (5), the forward slip of this stand and the deformation resistance of strip at the exit point are calculated, Fig. 4.Table 3 Experimental data of IMSC (case 2)Table 4 Comparison for final solution of constants of constitutive equation with different initial assumptionFig. 7 Variation of flow stress strain curve with the iteration for case 24 .Flow stress-strain curve of strip and friction coefficient computationIn Fig. 5, the flowchart of the developed algorithm in this study is presented with the related details in order to determine the friction coefficient and flow stress strain curve with respect to the actual mill data. It should be mentioned that the list of equations presented in Table 1 are applied in this flowchart. In reference to this newly developed flowchart, after the initial values of forward slip and constitutive equation constants are assumed, the new values are determined for the mentioned parameters. Under these circumstances, the difference ratio of the newly obtained values in sequential loops is less than the special value; convergence criteria is fulfilled.Fig. 8 Comparison of flow stress-strain between predicted and actual curve: a case 1 and b case 25 .Discussion and resultsA schematic diagram of a five-stand tandem cold rolling mill at IMSC is shown in Fig. 6. In each stand, the rolling force is measured by a load cell and the inter-stand tensions are measured by tension meters. Two sets of experimental data of IMSC are applied in verifying this developed algorithm. The material of the strip is St12. The rolling data of each case is listed in Tables 2 and 3. In the first case, the thickness of strip is reduced from 3 to 0.8 mm and in the second case is reduced from 2 to 0.57 mm. The yield stress of strip and Young modulus are determined by simple tension test by Zwick/Roell Z400 in quasi-static condition on a specimen of strip before rolling at IMSC. The algorithm runs with several initial assumptions for constants of constitutive equation to check whether convergence of the proposed algorithm takes place. The results of constitutive equations constants are compared with three initial assumptions for each case in Table 4. After checking the results with different assumptions, the behavior of the flow stress-strain curve in terms of iteration number for case 2 is shown in Fig. 7. The curves demonstrate how the constants of constitutive equation converge to the final solution as the iteration goes on. By considering the convergence criteria as being small, the predicted curve will correspond to the actual curve. It should be mentioned that the loops are converged in less than ten iterations. This algorithm is suitable for online calculations. The comparisons between predicted flow stress-strain curve from this algorithm and true stress-strain curve from simple tension test of both the cases are presented in Fig. 8. The calculated yield stress at fifth stand along with the strip yield stress obtained from simple tension test on the final product is tabulated in Table 5. The values obtained from forward slips and friction coefficients of all five stands in both cases are listed in Table 6. The values of friction coefficient in both cases of this study are obtained in the absence of velocity meter. The results are in a good agreement with the ones obtained in 3, where velocity meters were installed.Table 5 comparison of the calculated and actual values of yield stressTable 6 The forward slip and friction coefficient of each stand6. ConclusionIn this article, a new method for prediction of forward slip in the tandem cold rolling mill without the velocity meter sensors based on rolling geometry is described. According to this method, an algorithm is being developed for determining the online friction coefficient and the constants of constitutive equation of the strip for a five-stand tandem cold rolling mill. Through this algorithm, the upper and lower bound of forward slip and friction coefficient are determined for each stand and the mills control program works in a more accurate manner. The difference between calculated and measured rolling force is reduced and the possibility of strip tearing is decreased. The obtained results through the numerical samples are in good agreement with the results obtained for the same purpose where the mills are equipped with velocity meter.References1. Mashayekhi M , Torabian N, Poursina M (2010) Continuum damage mechanics analysis of strip tearing in a tandem cold rolling process. Simul Model Pract Theory 19:612625 2. Byon SM, Kim SI, Lee Y (2008) A numerical approach to determine flow stressstrain curve of strip and friction coefficient in actual cold rolling mill. J Mater Process Technol 201:1061113. Wang JS, Jiang ZY, Tieu K, Liu XH, Wang GD (2007) A method to improve model calculation accuracy of process control in tandem cold mills. 2nd IEEE Conference on Industrial and Electronics and Applications ICIEA, pp 27872790 4.Tieu AK , You C (2005) Material resistance and friction in cold rolling. 6th world congresses of structural and multidisciplinary optimization, Rio de Janeiro, 30 May3 June 2005, Brazil 5. Poursina M, Torabian N, Fattahi A, Mirmohammadi H (2012) Application of genetic algorithms to optimization of rolling schedules based on damage mechanics. Simul Model Pract Theory 22:6173 6. Sims RB (1952) The forward slip in cold strip rolling . Sheet Metal Ind 29:869877 7. Tselikov AI, Nikitin GS, Rokotyan SE (1981) The theory of lengthwise rolling. Mir, Moscow 1.2中文翻译一种冷连轧机前滑预测的新方法M. Poursina & M. Rahmatipour & H. Mirmohamadi摘要： 本文提出了一种无速度表传感器的串联冷轧机前向滑移的新方法。根据该方法，提出了一种在线估计摩擦系数和条纹行为的算法。在轧制过程中，摩擦系数的在线发挥和带钢的行为都得到了较好的控制。因此，不饱和致动器得到满足，撕裂的可能性降低。这条带子的材料是st12。该材料被认为具有弹塑性、同质性、同质性等特点。通过对试件试样的简单拉伸试验，确定了带钢的屈服应力和杨氏模量。对开发方案进行了验证，并对两种操作样本进行了考虑，并与现有文献进行了比较。关键词：冷轧压 前滑 摩擦 本构方程术 语：P 轧制力 t机架间的张力 D工作辊直径C, n本构方程的常数 R工作辊半径 R变形辊半径 W带钢宽度 中性点角 h带钢厚度 K带变形阻力 摩擦系数 fs前滑屈服应力 应变 R减少 L接触的长度 E杨氏模量 泊松比1介绍连续冷轧机组控制是一个复杂的过程。这一过程的目的是通过对轧制力和前滑的精确控制获得理想的条带厚度。测量和计算的轧制力和前向滑移之间的差值是饱和的致动器。在此情况下，串列冷轧机控制系统中最轻微的振动，可能会导致带钢撕裂1。轧制力和前向滑移依赖于不同的参数，特别是带钢的摩擦系数和力学性能。这些参数在滚动过程中变化，而在大多数控制程序中，它们被认为是常量。由于缺乏摩擦系数和本构方程常数的在线信息，一些研究人员提出了基于逆方法的模型，以确定摩擦系数和本构方程的在线大小。表1 方程、应用的流程图Byon等人通过采用逆方法2，在具有全传感器的可逆冷轧机中，瞬间确定了本构方程的摩擦系数和常数。Tieu等人3,4对四台架冷轧机带钢的摩擦系数和本构方程进行了评价，并给出了摩擦系数的适用模型。虽然在之前的工作中，轧制力和向前滑动都是通过载荷传感器和速度计传感器直接测量的。在一些带钢制造工厂中，由于现有轧机的标准形状不合格，或者由于各种原因，没有合适的位置安装速度计传感器，所以速度表不能够很好地记录条纹速度。在这种类型的轧制过程中，由于前向滑移量的不断增大，使得前滑块的测量精度不高，轧制过程的计算也不准确。图1 滚动几何和沿接触弧的辊压分布7图2 压力分布与中性点间张力、tf正向张力、tb反向张力的影响。这种缺陷导致轧制过程的计算中出现了更多的误差，当执行器饱和时，会发生条带撕裂，无法消除这些误差。在本研究中，提出了一种基于滚动几何的新方法，以预测一个不具备足够的速度计传感器或现有传感器的串联冷轧机组的前向滑移的在线模量。随后，通过逆算法，瞬时确定了带钢结构方程的摩擦系数和常数的大小。为了验证开发方案的有效性，研究了伊斯法罕Mobarakeh钢铁联合企业(IMSC)中5台立式冷轧机的两个样品。研究结果与相关文献的结果比较吻合。图3前向滑动和中性点位置的最大值图4 带钢的流动应力应变曲线2数学模型在此基础上，完成了滚动力、前滑、本构方程三个方程的同步解。第一个方程是轧制力模型:建议不同的轧制力模型来确定以下形式的轧制力: （1）在在线计算中，使用简单的方程是提高过程速度的关键。为了达到这个目的，我们选择了福特动力模型，即Eq.(2)。 （2）其中f1和f2分别为拉伸应力和摩擦系数的校正函数(表1)。第二个方程为正向滑移模型:当中性点每一侧的接触弧的压力分布相等6时得到。该方程表示为摩擦系数