铜包铝复合材料轧制变形过程模拟及轧制力计算公式

基于对铜包铝双金属复合材料轧制变形过程进行的有限元模拟,建立了双金属复合材料轧制变形分区模型,可分为弹性区、单材料塑性区、后滑区、揉轧区和前滑区.以铜的体积分数为变量,对不同铜含量的铜包铝复合材料的轧制过程进行模拟,在单一材料轧制力理论计算公式的基础上,提出了双金属复合材料轧制力的理论计算公式,通过对铜包铝复合材料轧制的试验和不同压下率下的铜包铝双金属复合材料轧制成形的有限元模拟,对所推导出的轧制力公式进行了验证.     

变厚度区薄板轧制的辊缝设定模型与试验

为实现高精度的变厚度轧制,需要对变厚度轧制的厚度控制模型进行研究.基于离散化的控制思想和轧制弹跳方程建立了一种TRB变厚度区轧制辊缝设定模型,用于单机架可逆式四辊冷轧机厚度控制系统.研究了辊缝变化的非线性规律,基于误差分析提出了确定离散区间的方法;给出了一种TRB辊缝控制系统结构以及空载辊缝闭环和负载辊缝闭环的控制方程,并在实验四辊轧机上进行了单厚度过渡区的TRB轧制.结果表明,采用离散化的辊缝设定方法可以实现TRB板的50 mm变厚度区,尺寸最大厚度偏差为0.08 mm,长度偏差<1 mm.     

宽厚板轧机轧制压力模型

1概述轧制力是轧机最重要的设备及工艺参数,是轧机零部件强度设计计算与校核,工艺规程的制定、轧机以及强化轧制的调整、设备潜力的挖掘等的重要参数。轧制力模型的主要作用是:设定辊缝值;计算厚控系统的增益;进行轧制道次的负荷分配;用于最优控制。轧制力模型的预报精度直接决定设定精度,也直接影响厚度和板型,还将影响到轧制过程的稳定性。轧制力通过模型计算,并通过长期自学习和短期自学习修正系数进行修正。轧件的变形阻力的计算等于轧件屈服应力乘以一个修正函数。这个修正函数与轧件的外部摩擦、内部摩擦和内部剪切有关。     

融合工业大数据的热轧厚板轧制力模型研究

目的针对传统解法建立的轧制力模型精度不足的问题,建立一个轧制力整合模型。方法对工业大数据进行归一化处理,系统优化了神经网络模型的结构形式,建立了一个神经网络模型。在此基础之上,利用误差间距补偿的方法实现神经网络模型与已有理论模型的有机融合,从而最终获得了轧制力的整合模型。结果通过与已有的轧制力模型进行对比,表明所提出整合模型预测结果与实测值吻合更好,其中轧制力误差为-4.09%,轧制力矩误差为-4.01%。结论该模型整合方法能够实现理论模型与神经网络模型的优势互补,从而给出物理概念与预测精度均可靠的计算结果。     

有摩擦弹性接触问题边界元分析的一种新方法

在将切向接触力与切向相对位移的关系表为带有惩罚因子的线性互补形式后,直接利用法向接触力与法向相对位移的互补关系,结合边界元技术,本文给出了一种新的求解有摩擦弹性接触问题的数学规划法。     

精确钢板测厚优化轧制模型控制的研究与应用

济钢中厚板厂精轧机钢板测厚自动控制系统是精轧机自控系统的一部分,是德国Thermo Radio meter RW GmbH公司的产品--λ射线测厚系统,用于在线测量、扫描,并对所得数据与该钢种的材质、成分综合分析,利用程序的曲线模型计算出理论数据作为反馈值送至精轧机二级系统.用于自动补偿,二级系统根据该数据计算出下一道的压下量等,从而为实现自动轧制提供了有力保障.     

设计意念的真实再现一件包装设计作品的电脑制作过程

如何更好地展现设计效果,这是许多设计师在与客户或受众进行交流或沟通时遇到的难题之一,当一个绝妙的创意酝酿于设计师的头脑之中,却无法以最好的效果呈现在客户或受众面前时,这种压抑是很令人郁闷的。带着“如何再现设计意念,让设计思维活跃起来、使设计意念具体而真实地再现于生活面前“这一难题,许多设计师在设计过程中不约而同地选择了”计算机辅助     

一种指甲油自动包装生产线的设计与实现

目的为了提高指甲油包装生产线的效率,降低人工成本,实现机器替代人工的目标,应某指甲油生产企业的要求提出一种指甲油自动包装生产线方案,并研制出实现指甲油自动化包装生产的包装生产线。方法通过分析某指甲油生产企业的指甲油包装生产过程,采用Solid Work软件分别建立空瓶放置、钢珠放入空瓶、指甲油注入、瓶盖放置、拧入瓶盖和成品输出等装置的三维模型,并对组成各装置的零部件进行图纸设计。利用西门子S7-200 PLC控制各机构的AC电机和气缸的协调运作,实现指甲油的自动化包装生产。结果研制出了一种指甲油自动包装生产线,实现了指甲油的自动化包装生产,满足了企业要求。结论该指甲油包装生产线解决了指甲油自动化包装的难题,实现了机器替代人工的目标,提高了指甲油包装生产效率。     

一种叶片干摩擦阻尼器耦合振动分析的二维局部摩擦模型

从一维局部滑动模型和轨迹跟踪法出发,采用带滑动触点的并联弹簧来模拟二维平面运动时叶片-阻尼器间的干摩擦接触,提出一种二维局部滑动摩擦模型。推导了各种摩擦接触情形下的摩擦力计算公式,通过仿真深层次揭示了二维局部滑动的规律。结果表明,二维局部滑动与一维局部滑动相比既有一致又有本质不同,二维局部滑动模型可用于叶片干摩擦阻尼器耦合振动特性的分析。     

Role of Friction in Cold Ring Rolling

1. Introduction Cold ring rolling is a main technology used to manu- facture various precise seamless ring shape parts. It has been increasingly used in many industrial fields such as bearing, machine, automobile, petrochemicals, aeronau- tics, astronautics and atomic energy because of its many technical superiorities such as considerable saving in en- ergy and material cost, high quality, high efficiency, and low noise, etc. To research and develop advanced precise cold ring rolling technolog…     

轧制力模型自适应在神经元网络预报轧制力中的应用

在中厚板生产过程中,神经元网络已经运用到中厚板轧制力模型预报中,但是与实际的轧制力相比还存在着较大的误差。为了提高神经元网络预报轧制力精度,将轧制力模型的自适应过程引入到神经元网络用于轧制力预报,应用结果表明,采用本文所述的方法,神经元网络的预测精度得到很大改善,预报精度的相对误差可以控制在±3％以内。     

Solids Friction Factors for Fluidized Dense-Phase Conveying

There have been numerous correlations proposed for determining a solids friction factor ( λs ) for fully suspended (dilute phase) pneumatic conveying. Currently, there are no equivalent correlations that predict λs in nonsuspension dense-phase flows. In dense-phase conveying there are two basic modes of flow: plug/slug flow, which is predominantly based on granular products, and fluidized dense-phase flow, which is more suited to fine powders exhibiting good air retention capabilities. In plug/slug type flow, the stresses between the moving plug of material and the pipe wall dominate the solid-phase frictional losses. In fluidized dense-phase flow the frictional losses are characterized as a mixture of particle-wall and particle-particle losses but are heavily influenced by the gas-solid interactions. In this paper, a series of calculations were performed on experimental data in order to estimate λs for four types of material conveyed in the fluidized dense-phase flow regime. The solids frictional factors were found to be relatively independent of particle properties for varying air and solid mass flow rates and pressure drops. The resultant pressure drop from the empirical model showed good agreement with the experimental data.     

Numerical Modeling of Friction Stir Welding Process by Using Rate-dependent Constitutive Model

Rate-dependent constitutive model was used to simulate the friction stir welding process. The effect of the viscosity coefficient and the process parameters on the material behaviors and the stress distributions around the pin were studied. Results indicate that the stress in front of the pin is larger than that behind the pin. The difference between the radial/circumferential stress in front of the pin and that behind it becomes smaller when the material gets closer to the top surface. This difference increases with increasing the viscosity coefficient and becomes smaller when the welding speed decreases. The variation of the angular velocity does not significantly affect the difference.     

Effect of ZrSiO4 on the Friction Performance of Automotive Brake Friction Materials

Friction-wear properties of the ZrSiO4 reinforced samples were measured and compared with those of plain bronze based ones. For this purpose, density, hardness, friction coefficient wear behaviour of the samples were tested. Microstructures of samples before and after sintering and worn surfaces were also investigated by scanning electron microscopy （SEM）, and the wear types were determined. The optimum friction-wear behaviour was obtained in the sample compacted at 500 MPa and sintered at 820℃. Density of the final samples decreased with increasing the amount of reinforcing elements （ZrSiO4） before pre-sintering. However after sintering, there is no change in density of the samples including reinforcing elements （ZrSiO4）. With increasing friction surface temperature, a reduction in the friction coefficient of the samples was observed. However, the highest reductions in the friction coefficients were observed in the as-received samples containing 0. 5% reinforced ZrSiO4. The SEM images of the sample indicated that while bronze-based break lining material without ZrSiO4 showed abrasive wear behaviour, increasing the amount of ZrSiO4 resulted a change in abrasive to adhesive wear mechanism. All samples exhibited friction-wear values, which were within the values shown in SAE-J661 standard. With increasing the amount of reinforcing ZrSiO4, wear resistance of the samples was increased. However samples reinforced with 5% and 6% ZrSiO4 showed the best results.     

复合材料滚动轴承粘弹性分析

本文建立了短切纤维增强塑料复合材料滚动轴承的力学模型，采用三维有限元法求解粘弹性各向异性力学问题，得到了较精确的粘弹性应力场和应变场，并用实验验证了有限元计算结果。     

Automotive Friction Materials: from Experience to Science

An optimizing friction material formulation technique based on Golden Section and Relational Grade Analysis was developed. Approach 2 of this technique was tested by using 7 ingredients including 2 fibers, 4 fillers and 1 binder as raw materials. By doing 19 formulations, an optimizing one (BU18)was obtained with stableμ and averageμ = 0.451 and wear = 3.46 wt %.     

Sliding Friction of Al-Cu-Fe-B Quasicrystals

Dry sliding friction between the Al_59Cu_25.5Fe_12.5B_3 quasicrystals (QCs)/coating of the diamond-like carbon (DLC) was carried out by self-made tribometer under different conditions. The influences of four parameters (temperature, sliding velocity, applied load, atmosphere) on friction and wear of quasicrystal surface were studied. Microstructure of quasicrystal, morphology of worn surface, and wear debris were observed by scanning electron microscopy (SEM). The results showed that for QCs, the friction coefficient and roughness of worn surface were influenced by the parameters, especially greatly by the temperature. With rise of the applied load and sliding velocity, the friction coefficient decreased. The dominant wear mechanism at 350℃ was delamination for QCs. The cracks formed on the worn surface during the friction. Moreover, phase transformation was not observed on worn surface of QCs at 350℃. All the results are discussed and explained.     

热喷涂技术在摩擦磨损领域应用研究

该文综述了热喷涂技术在摩擦磨损领域应用的研究现状及进展,主要论述了喷涂方法、喷涂工艺、喷涂材料、涂层结构、涂层处理及喷涂涂层的磨损机理等方面在摩擦磨损领域的研究与进展,通过上述几方面的讨论与分析,总结了热喷涂涂层在摩擦磨损领域具体的应用情况,分析和总结了热喷涂涂层在摩擦磨损领域应用失效的主要原因和形式,并提出了提高热喷涂技术在摩擦磨损领域应用能力的方法和措施。     

应用自适应模糊神经网络进行摩擦补偿的研究

在分析了摩探性及其对伺服系统低速特性的影响的基础上,提出了一种基于自适应模糊神经网络的摩探辨识和补偿方法,该方法既可实现摩探力矩的在线辨识和补偿,又能保证系统的稳定性。仿真结果表明,该方法是有效的,而且便于工程应用。