拉弯矫直机结构研究及基本工艺参数确定方法探析

对拉伸弯曲矫直的作用机理进行了阐述;结合带材的受力状态,对拉弯矫直机的类型及张力辊、弯曲矫直辊的机构进行了分析说明;根据实际操作经验及设备设计厂家提供的经验数据,对机列的主要工艺参数——延伸率的确定方法进行了论述。     

拉伸弯曲矫直机张力辊传动装置分析

拉伸弯曲矫直机被广泛应用在冷轧生产线中,用于提高带材平整度,减少残余应力,以及在带材酸洗前进行破鳞,拉伸张力和带材延伸率由机前机后张力辊实现,而张力辊的传动方式各有不同。为此对拉伸弯曲矫直机张力辊传动装置进行简要分析。     

拉伸弯曲矫直机在铝带精整中的应用研究

论述了拉伸弯曲矫直机在铝带精整中的作用,参数对矫直效果的影响。拉伸弯曲矫直机属于高端有色金属精整加工设备,通过对带材的拉伸弯曲作用,能够有效地消除薄带波浪和翘曲等板形缺陷。在实际生产过程中,由于来料板型的不规则性,需要根据实际情况来调整机组参数。深入分析带材拉矫过程中拉力、矫直切入量、带材延伸率等关键技术参数对矫直效果的影响,以及各个参数的设定原则。带材的来料质量决定了延伸率的设定,在拉力达到最大的情况下,可通过调整切入量使拉矫效果达到最优。     

拉伸弯曲矫直机的结构设计理论分析

论述拉伸弯曲矫直机的结构、工作原理,设计拉弯矫直机的理论依据。     

拉伸弯曲矫直机的结构设计理论分析

论述拉伸弯曲矫直机的结构、工作原理,设计拉弯矫直机的理论依据.     

拉伸弯曲矫直机的结构设计理论分析

论述拉伸弯曲矫直机的结构、工作原理，设计拉弯矫直机的理论依据。     

薄带钢拉矫机浪形矫平过程机理建模及有限元验证

采用弹塑性力学分析方法,针对拉伸弯曲矫直机用于对具有初始位移缺陷(瓢曲浪形)薄带钢的浪形矫平过程进行机理建模,推导建立以带钢规格材质及初始浪形参数、拉矫工艺参数和拉矫机相关设备参数为自变量的拉矫变形过程浪形矫平功效的解析预测模型。通过定义拉矫过程中带钢宽向进入塑性变形的屈服区域边界位置作为中间变量,以及依次分别建立各项输入条件与屈服位置的关系、屈服位置与工艺条件的关系,建立浪形矫平预测模型的多变量微分方程组。为了验证该机理模型的正确性,分析初始浪形、材料强度、带钢尺寸等初始条件以及弯曲辊半径、拉矫张力等工艺条件对拉矫机对于带钢浪形的矫平改善能力的影响,并应用ABAQUS软件另行建立同样条件下薄带钢拉弯矫直过程的有限元模型,经计算并对比计算结果,两种方法的结果吻合良好。     

拉伸弯曲矫直机张力与弯曲的配置关系研究

拉伸弯曲矫直机主要依靠现场经验进行张力与弯曲配置。为实现张力与弯曲作用在拉矫时的合理配置,在分析带材极限弯曲曲率计算方法的基础上,引入极限弯曲曲率修正系数,探讨其取值规律,并将极限弯曲曲率修正值作为拉矫时的最大曲率,得出拉矫时最大弯曲曲率和最小张力的确定方法,在满足平直度要求情况下,求得较优的拉矫工艺参数。通过实际验算,所得结论是合理可行的。     

挤压-弯曲一体化成型铝合金弯曲型材的质量与性能

通过改造传统挤压机,增加弯曲装置,对铝合金型材进行挤压-弯曲一体化成型,研究了辊轮半径和辊轮移动速度对成型质量的影响,基于有限元模拟获得了辊轮半径和辊轮移动速度等最佳工艺参数。结果表明:当型材挤出速度与辊轮移动速度相同时,铝合金型材的成型性较好;挤压-弯曲一体化成型工艺避免了传统拉弯工艺存在的回弹、表面划伤和截面变形等缺陷,提高了弯曲型材力学性能的均匀性。     

小型专用拉弯矫直机的设计与工艺研究

镀锌薄钢带经常大量应用于冷弯型钢生产中,而在其生产过程中很容易出现板形缺陷。常见的辊式弯曲矫直设备通过单纯弯曲变形对钢带实施矫直,但无法胜任薄带复杂板形的矫正。拉伸弯曲矫直方法将拉伸和弯曲两种矫直工艺相结合,改变了钢带中性层的位置,经过多次拉直、弯曲能够实现钢带全截面延伸,能够同时实现钢带侧弯、波浪变形、坯料楔形等不良板形的矫直。为此我们开发了一种专门用于冷弯生产的小型拉弯矫直设备实现薄钢带的矫直功能。不但详述了设备机械、电气的研制与开发,而且采用有限元分析和现场试验相结合的方式,对特定产品的拉弯矫直工艺进行了研究。     

A novel dynamic opto‐thermo‐mechanical stress testing device 1: Design of the device

This article presents a dynamic opto‐thermo‐mechanical stress testing device to characterize fiber properties. The device has multi‐modes and consists of many functions. These modes include stretching, bending, rotating, twisting, and heating processes. Every process can be controlled by micro‐controller unit via software programs specially designed for this purpose. The micro‐controller unit can execute two different processes at the same time. Such as, dynamic stretching process under the effect of thermal treatment, dynamic stretching process and relaxation, bending process under the effect of thermal treatment, and so forth. Software programs with their flow charts are designed for the application of these processes. The advantage of this device is that it can be done statically and dynamically to characterize all types of fibers (polymer and optical). The device is designed to be attached with two‐beam polarizing interference microscope to investigate the dynamic opto‐thermo‐mechanical properties of the tested fiber under the effect of different applied stresses. Isotactic polypropylene, iPP, fiber is used for some applications of this device, as examples, in stretching, rotation, and twisting modes. Interferograms and graphs are given for illustration.     

宝钢厚板激光平直度仪

现代宽厚板生产过程对仪表的自动检测和精度控制要求很高，现代化宽厚板的生产工艺决定了特殊检测仪表的重要性，在保证产品的质量及精度方面，全自动非接触特殊检测仪表起到了重要的作用。宝钢厚板厂应用的平直度仪采用激光测量方式，位于热矫直机后，为热矫模型提供可靠有效的平直度数据。主要介绍激光平直度仪在宝钢厚板厂的应用及其测量原理，分析平直度与延伸率之间的关系，研究平直度测量结果如何用于板形的控制。     

Numerical study of droplet dynamics impinging onto steel plate covered with scale layer

The steel hot rolling process is inseparably connected to an oxide layer called “scale” at high temperatures. Hydraulic descaling of rolled material is a part of all rolling trains. Surface quality after descaling is fundamental for the final surface quality of a rolled product. The process itself is not theoretically well described; various different approaches have been used to clarify the descaling problem. This paper describes the dynamics of high-speed impact between the compressible water droplet and the steel scale layer. The phenomenon is known as water hammer effect. The purpose of this study is to numerically verify the fact that impact stress can be a significant factor during the descaling process. Considering a high droplet impact speed (100–300 ms⁻¹), inferential extremely short time interval (0.1–5 μs) peaks in impact pressure reaching 300 MPa can be found. Droplet dynamics was simulated with the help of LS-Dyna solver, whereas the stress analysis was performed in ANSYS interface. The extreme pressure peaks of very short duration in an impact area are a new phenomenon in the descaling theory.     

Evaluation of cellulose electro-active paper made by tape casting and zone stretching methods

Cellulose has been discovered as a smart material that can be used as sensor and actuator material. In this paper, cellulose smart material termed as electro-active paper (EAPap) is prepared by an automated process that includes tape casting and zone stretching. To evaluate characteristics of the EAPap, its Young’s modulus and piezoelectric charge constant are measured depending on the orientation angle, in comparison with the manually fabricated EAPap results. The zone stretching method can effectively align the cellulose fibers in the EAPap so as to improve its Young’s modulus as well as piezoelectric charge constant. The 0 degree oriented sample shows its maximum Young’s modulus and the 45 degree oriented sample exhibits the maximum piezoelectric charge constant. This 45 degree is associated with its shear piezoelectricity. The actuator performance of EAPap is evaluated by measuring its bending displacement depending on the orientation angle and the excitation voltage. The 45 degree oriented sample exhibits the maximum bending displacement. Details of the material preparation, the automation process, characterization and the actuator performance are addressed. This automated process that includes tape casting and zone stretching is suitable for mass production of the EAPap.     

压电智能梁的静态耦合模型

利用力平衡原理，建立了单面粘贴有压电致动器的梁结构的静态拉伸－弯曲耦合模型，在分析过程中，考虑了梁与致动器之间粘贴层的影响。通过分析可得，粘贴层剪切应力的分布与致动器端部附近的应变分布有相似的特征。随着粘贴层的剪切模量的增加或其厚度的减小，剪切力在靠近压电致动器端部区域迅速增大。     

薄壁叶片精密加工装夹方案设计与优化

针对航空发动机薄壁叶片刚性弱、加工工艺性差、加工过程中易发生弹性变形等问题,提出了无预载荷、有轴向拉压载荷的装夹方案,分析了3种装夹方案中的弯曲和扭转变形,建立了叶片的弯扭组合变形数学模型。通过对叶片弯扭组合变形数学模型的分析,得出了3种装夹方案下叶片几何尺寸与叶片加工变形位置的关系,以及拉压载荷对叶片加工变形的影响规律。     

Optimization of forming steps in the incremental forming of twisted shapes using a line array roll set (LARS)

The line array roll set (LARS) process is an effective metal forming process used to manufacture doubly curved metal plates. This study describes process optimization of forming steps that can be used to form a twisted shape. In the incremental forming of a twisted shape using the LARS process, a defect near the edge of the formed shape was observed. A plate was subjected bending and twisting simultaneously by the roll sets as part of this process; therefore, it was assumed that the edge defect resulted from the excessive longitudinal strain near the edge region of the plate. To obtain a desired shape with more precision and to minimize any possible defect, the process of forming the desired shape should be systematically and accurately designed. To obtain the optimized design and to ensure that the maximum longitudinal strain is under the limit of the critical value, an iteration scheme is used for the optimization. Edge profiles of deformed shapes for both a non-optimized design and an optimized design were compared. From the comparison, it was found that the optimized design can minimize the number of forming steps by decreasing the edge wave caused by excessive edge stretching.     

拉伸弯曲矫直机齿轮箱系统动态特性分析

齿轮箱作为拉伸弯曲矫直机的主要组成部分,其运行状况的稳定性对拉伸弯曲矫直机机组及带钢产品的质量有着重要影响。利用三维建模软件建立齿轮箱系统的三维实体模型,再运用有限元仿真软件对齿轮箱系统整机进行了模态分析和谐响应分析(激励为齿轮之间啮合所形成的冲击激励),分析结果与实测结果相符,得到了齿轮箱系统的整体动态特性,为拉伸弯曲矫直机组结构调整及调整后系统振动特性的预测提供参考。     

In-plane vibration analysis of cantilevered circular arc beams undergoing rotational motion

Equations of motion of cantilevered circular arc beams undergoing rotational motion are derived based on a dynamic modeling method developed in this paper. Kane’s method is employed to derive the equations of motion. Different from the classical linear modeling method which employs two cylindrical deformation variables, the present modeling method employs a non-cylindrical variable along with a cylindrical variable to describe the elastic deformation. The derived equations (governing the stretching and the bending motions) are coupled but linear, so they can be directly used for vibration analysis. The coupling effect between the stretching and the bending motions, which could not be considered in the conventional modeling method, is considered in this modeling method. The effects of rotational speed, arc angle, and hub radius ratio on the natural frequencies of the rotating circular arc beam are investigated through numerical analysis.