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轧机辊间压力和轧制压力分布函数解析 总被引:7,自引:0,他引:7
通过对轧辊变形及轧辊间接触条件的分析,证明了辊间压力和轧制压力多顶式分布假设的局限性。根据压力耦合求解模型导出了试验结果吻合的轧制压力和辊间压力分布函数。 相似文献
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四辊轧机轧制压力横向分布的计算 总被引:5,自引:0,他引:5
采用有限元方法确定四辊轧机轧制压力沿横向分布问题时,由于在工作辊及支撑辊之间存在着未知接触压力和位移,因而该问题无法用简单方法求解。根据辊系变形与受力的特殊性对方程进行变换并由实测钢板的截面形状以及轧制压力、弯辊力参数可解出辊系各点的位移;由力—位移的关系可以计算出给定工况下轧制压力的分布。计算结果与国内外研究结果相吻合。该计算方法可用于完善及优化辊系变形数学模型。 相似文献
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板凸度和平直度是衡量板形质量的重要指标,它们既相互独立又彼此相互作用,而板凸度主要取决于有载辊缝的形状,所以准确计算辊系的弹性变形,对辊缝的设定有重要意义。采用影响函数方法对UCM轧机的辊系弹性变形进行了系统分析,通过修改工作辊、中间辊和支撑辊的影响函数模型,建立更适合现场的模型,用Vsual Basic语言编写计算流程的程序,设定初始数据,采用Bland—Ford轧制力计算公式进行计算。通过计算,第1机架轧制力的计算值与实测值相差8.2%,后面各机架与实测值更为接近,因此,所用方法是可行的。进一步分析得出影响有载辊缝形状的诸因素(辊间压力、辊间压扁、轧制力、挠度、弯辊力等)的结果,并与现场进行比较,达到提高板形质量的目的。 相似文献
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为减少冷轧带钢的非对称板形缺陷的产生,设计了工作辊非对称弯辊控制系统.应用影响函数法计算辊系变形,同时考虑辊缝中金属横向流动对带钢出口横向张力分布的影响,通过迭代法计算出工作辊两端施加不同弯辊力后的辊间压力分布、出口厚度横向分布以及出口横向张应力分布.理论分析结果表明,工作辊非对称弯辊可以在一定程度上改善辊间压力分布不均,减轻轧辊磨损和减少轧辊掉皮事故的发生,降低带钢边部的非对称板形缺陷.实际应用结果证明,当倾斜调整量小于10%时,应用工作辊非对称弯辊替代倾斜调整,可以获得更好的板形精度. 相似文献
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轧制压力横向分布规律对快速轧辊轧件一体化模型的建立、轧辊磨损及辊形预测具有重要的意义。为简洁有效地描述轧制压力横向分布,提出了轧制压力横向分布表征指标,即边中比、高次程度、一次非对称度及三次非对称度。通过有限单元法建立了轧件三维弹塑性变形模型,并根据实测数据对模型边界条件进行设置,研究了不同因素影响下的轧制压力横向分布规律。考虑到各生产因素对轧制压力横向分布的影响不完全独立,不易获得函数表达式,以多组工况下有限元仿真结果为基础,建立多生产因素影响下的轧制压力横向分布人工神经网络预测模型,为轧辊轧件一体化快速计算模型的建立奠定了基础。 相似文献
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通过引人变形系数的概念,建立了三维变形时高向、宽向应力间关系,并以此为基础推导了全主动四辊组合孔型轧制时的单位压力和轧制力的差分公式。轧制力计算结果与试验结果吻合较好。 相似文献
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CVC轧机辊间接触压力分布不均,辊间压力峰值易引起严重的支撑辊不均匀磨损,甚至造成轧辊的剥落。采用影响函数法,分析了轧件宽度、工作辊横移位置、弯辊力以及支撑辊凸度对辊间压力分布的影响;研究了在应力集中最严重的横移位置时,支撑辊端部采用圆弧形倒角和抛物线形倒角时,倒角参数变化对辊间压力分布的影响规律。结果表明:CVC轧机辊间压力成S形分布,在轧辊右端存在较大的应力集中;轧件越宽,应力集中越严重;横移位置为负向最大时,辊间应力集中最严重;增加支撑辊凸度能减小辊间接触压力的峰值,但是对辊间压力分布的改善不明显;弯辊力对辊间压力有较大的影响;使用合适的抛物线形倒角和圆弧形倒角均能很好的减小辊间接触压力的峰值,并使辊间压力分布更均匀。研究结果可为CVC轧机支撑辊辊形设计提供理论依据。 相似文献
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The present study examines the effect of cavitation on the base pressure coefficient of a circular cylinder. The tests are conducted at near-constant Reynolds numbers (≈105) and a wide range of cavitation numbers. The degree of cavitation varies from noncavitating flow, to inception, to near-choking conditions. Pressure measurements along the wake axis are also obtained at various cavitation numbers. The similarity of the wake axis pressure distribution is investigated. 相似文献
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The behavior of transients in water pipe networks is well understood but the influence of modulating control valves on this behavior is less well known. Experimental work on networks supplied through pressure reducing valves (PRVs) has demonstrated that, in certain conditions, undesirable phenomena such as sustained or slowly decaying oscillation and large pressure overshoot can occur. This paper presents results from modeling studies to investigate interaction between PRVs and water network transients. Transient pipe network models incorporating random demand are combined with a behavioral PRV model to demonstrate how the response of the system to changes in demand can produce large or persistent pressure variations, similar to those seen in practical experiments. A proportional-integral-derivative (PID) control mechanism, to replace the existing PRV hydraulic controller, is proposed and this alternative controller is shown to significantly improve the network response. PID controllers are commonly used in industrial settings and the methods described are easy to implement in practice. 相似文献
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Karen E. Dow Ambtman F. E. Hicks P. M. Steffler 《Canadian Metallurgical Quarterly》2011,137(4):399-411
Discrete ice floes approaching an ice cover from upstream will contribute to the lengthening of the cover or will become entrained in the flow. Currently, ice process models rely on empirical relationships to predict the behavior of ice floes at the leading edge of an intact ice cover. Knowledge of the hydrodynamic forces acting on individual ice floes is an important component of any model attempting to predict ice-cover progression. Experimental studies were conducted in a recirculating flume in the T. Blench Hydraulics Laboratory at the University of Alberta to increase the knowledge of the physical behavior of ice floes in water and the hydrodynamic forces that act on them. A hollow Plexiglas acrylic ice block outfitted with pressure taps was constructed to facilitate measurements of the pressure distribution beneath an ice block. The dynamic pressure was measured under the block for various block thickness-to-depth ratios and flow velocities. The dynamic pressure was found to decrease for increasing block thickness-to-approach flow depth ratios and increasing flow rates. A block with a rounded leading edge was also tested, and it showed a significantly reduced leading-edge pressure effect. The rectangular ice block results were categorized into separate effects: a pressure reduction attributable to Venturi effects and a pressure reduction attributable to leading-edge effects. A predictive relationship was developed for the pressure distribution beneath a floating ice block and the subsequent submerging force and underturning moment. 相似文献
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在建立了铸造区,轧制区轧制压力模型的基础上,对常规铸轧条件进行了仿真计算,计算结果与实测数据相吻合,从而验证了模型的正确性,在此基础上,对超薄快速铸轧条件进行了虚拟仿真研究,研究结果表明:不增强铸轧辊内,外冷却能力的条件下,而仅仅减薄铸轧 板坯厚度即可提高铸轧速度,在其它工艺参数保持不变,且保持出口温度与常规铸轧时基本相近的出口温度时,铸轧 厚度 薄时轧制压力比常规铸轧高,随着铸轧速度与铸轧区增大,铸轧坯厚度减薄,铸轧 辊径增大,轧制压力峰值增大。 相似文献
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《铜业工程》2017,(4)
溜井井筒一般装有成千上万吨矿石,其生产的压力是作用于井筒底板和井壁上。球缺内矿石产生的压力作用于井筒底板;球缺高度除与矿石性质有关外,与井筒半径成正比。绝大部分矿石以移动平衡拱的形式产生的力,作用于井壁上,可分解为对井壁垂直的和向下的两个分力。前者起到支撑井壁的作用;后者与矿石和井壁产生的摩擦阻力相平衡。井筒中矿石移动平衡拱的拱高,除与井筒半径成正比外,与矿石和井壁之间的摩擦角大小有关。溜井井筒贮满矿,可消除井壁受到卸矿冲击产生的局部磨损和其引起的破坏;存矿对井壁有很好的支撑作用;同时也大幅度减少溜井放矿时,井筒产生堵塞的概率。因此,满井放矿是使用和管理好溜井放矿的重要关键措施之一。 相似文献