共查询到20条相似文献,搜索用时 15 毫秒
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建立了冷轧带钢板形应力分段接触式检测过程的ANSYS有限元模型,引入欧式距离方法表征检测误差,分析了在不同板形缺陷模式下,板形辊弯曲变形、板形辊分段区域宽度、板形辊直径、带钢包角、带钢厚度、卷取张力、带钢张力横向分布不对度等因素对板形检测精度的影响。仿真结果表明:随着板形辊弯曲变形程度的增大,板形应力检测精度大幅度降低。随着板形辊分段区域宽度的增大,板形检测精度大幅度降低;而随着板形辊分段区域宽度的减小,板形检测精度提高,但提高的幅度随着分段区域宽度的减小而越来越小。卷取工艺张力越低,板形检测精度越低;且当卷取张力增大到某一值时,再继续增大卷取张力对板形检测精度影响甚小。随着卷取张力横向分布不对称度的增大,板形检测精度降低。板形检测辊直径大小、带钢包角的变化以及带钢厚度的变化对板形检测精度没有影响。 相似文献
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提出一种模拟板带轧制过程三维变形的新的数值方法——条层法。首先沿高向将变形区均匀地划分为若干层,然后再沿着金属的流动轨迹将变形区内的每层带材划分为若干流线条元,为了方便分析和计算,又将流线条元映射为矩形条元。横向位移的纵向分布被构造为四次曲线,横向分布用三次样条插值函数表示,高向分布用二次曲线拟合。根据塑性力学流动理论,分析推导了变形区三维变形和应力的数学模型。与作者曾经提出的流线条元法相比,考虑了应力与变形沿高向的不均匀分布,实现了精确的三维分析和计算。关于热带钢连轧和厚板轧制的仿真实例表明,提出的方法和模型符合实际,为板带轧制过程的三维力学仿真提供了一个新的实用工程数值方法。 相似文献
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Ridge-buckle defects in cold rolled thin strip originate from the formation of ridges in hot rolled coil and corresponding ridges left in the strip following annealing, cold rolling and tempering. A numerical solution was developed to calculate three-dimensional stress distribution in a wound coil built up wrap-by-wrap and subsequent flatness change in the uncoiled product. The model takes into account both nonlinear compressible characteristic of interwrap layer and uneven strip profile, especially ridges, on the stress evolution during the coiling process. The sensitivity of ridge-buckle defects in cold rolled thin strip to ridges in hot rolled coil profile has been investigated in details. The results show that the ridge-buckle defects in tin plate are much dependent on the height, width and location of ridges in hot coil profile. The permissible tolerance of ridges in hot rolled coil, below which does not produce the ridge-buckle defects in subsequent cold rolling of thin strip, are recommended for different steel grades. 相似文献
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Hermann-J. Kopineck Rudi Löffel Heiner-B. Otten 《Journal of Nondestructive Evaluation》1993,12(1):13-19
In the manufacture of sheet metal, it is ofgreat importance that the quality should be homogeneous over the entire length of a strip. This can only be monitored using a continuous, on-line measuring method. A new X-ray transmission measuring technique has been developed for the nondestructive determination of texture-dependent technological data of rolled strip. It can be applied on-line for both hot and cold rolled metal strip, especially steel strip. The paper describes the measuring principle and gives information on the application for measuring ther
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-values and the earing-values of cold rolled steel strip. With the data from these values, the user can control the deep drawing characteristics of his strips. The extension of the basic measuring principle to a condition-free determination system will be demonstrated with its application for measuring texture dependent technological data of hot and cold rolled steel strip. Long term experience at Hoesch Stahl AG, typical results measured over the total strip length, integration in quality assurance systems, questions of maintenance, etc. will be discussed. 相似文献
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A modern fringe-pattern-analyzing interferometer with a resolution of 1 x 10(-9) and without exclusion of systematic uncertainties owing to optic effects of less than 1 nm was used to test a new method of interferometric length measurement based on a combination of the reproducible wringing and slave-block techniques. Measurements without excessive wringing film error are demonstrated for blocks with nominal lengths of 2-6 mm and with high surface flatness. The uncertainty achieved for these blocks is less than 1 nm. Deformations of steel gauge blocks and reference platens, caused by wringing forces, are investigated, and the necessary conditions for reproducible wringing are outlined. A subnanometer uncertainty level in phase-change-correction measurements has been achieved for gauge blocks as long as 100 mm. Limitations on the accuracy standard method of interferometric length measurements and shortcomings of the present definition of the length of the material artifact are emphasized. 相似文献
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描述了一种基于斜率传感器的大型硅晶片平面度扫描测量系统.采用二维斜率传感器对晶片表面扫描,以获得表面绕X和Y轴的倾斜度.斜率传感器装在X向滑板上,而晶片固定在可绕Z轴转动的主轴上.对斜率传感器Y向的输出积分,得到晶片表面各个同心圆上轮廓截面高度.对斜率传感器X向的输出积分,得到晶片表面沿X向的截面轮廓,从而获得各同心圆轮廓之间的关系.构建了一个包括基于自准直原理的小型斜率传感器、气浮主轴、气浮导轨的实验系统,提出一种斜率传感器现场标定方法,用此系统测量了直径300mm的硅晶片平面度。 相似文献
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对16根转换柱试件和1根钢筋混凝土柱对比试件采用“建研式”加载设备完成了低周反复荷载试验,用于研究转换柱的基本抗震行为。建立了转换柱中钢与混凝土的相互作用方式及型钢的受剪模型,并以此为基础分析了型钢延伸高度、型钢配钢率、箍筋配箍率及轴压比对转换柱侧移刚度及侧移刚度退化速率的影响。采用反弯点法计算了转换柱的弹性侧移刚度。通过对试验数据的回归分析,同时引入截面抗弯刚度折减系数用于考虑裂缝及混凝土塑性发展的影响,得到了转换柱屈服点侧移刚度的计算公式,计算值与试验值吻合。 相似文献
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In order to improve the quality of the strip for the hot continuous rolling, the high accuracy set-up control must be applied to production. In the paper, we analyze the PFC (profile and flatness control) system and simulate the set-up process. Calculation results are in agreement to the actual measurements. It is the basis on the developing model. 相似文献
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钢框架延性好,但抗侧承载力和刚度较小,一般可加设钢板墙等抗侧力构件来达到结构的抗侧需求。屈曲约束钢板剪力墙是一种新型抗侧力构件,通过面外约束板的限制,钢板墙在剪力下不会发生屈曲破坏,因此其抗侧刚度、承载力和延性均较大。屈曲约束钢板剪力墙钢框架不但大大提高了原框架的刚度和承载力,同时还具备良好的延性。考虑到加设钢板墙后,框架梁的抗剪刚度与承载力可能不足,该文选取研究的屈曲约束钢板墙除了上下端与框架梁连接外,部分还与框架柱连接。对于这种新型内嵌屈曲约束钢板墙钢框架,该文从理论上详细推导了结构的抗侧刚度、屈服承载力等力学性能参量计算方法,得到了相应的理论公式。通过相关文献的试验数据对比,发现理论计算值与试验值很接近。 相似文献
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Application of Time-Domain Reflectometry for Measurement of Moisture Profiles in a Drying Experiment
Z. Pavlík J. Mihulka L. Fiala R. Černý 《International Journal of Thermophysics》2012,33(8-9):1661-1673
The time-domain reflectometry (TDR) method is used for the measurement of moisture profiles in calcium silicate during a drying experiment. The specimens are saturated at first by water, and their lateral sides and one of the face sides are water- and vapor-proof insulated to ensure one-dimensional (1-D) water transport. Then, the drying process is started in an environment with a relative humidity of 20%. Moisture profiles are measured at specified time intervals using the TDR method. The experiment is stopped when the moisture content along the whole length of the sample is lower than the maximum hygroscopic moisture content. The obtained results can be used for the determination of moisture diffusivity in the drying phase of moisture transport. 相似文献
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基于能量法对冷弯薄壁型钢卷边槽形截面的弹性畸变屈曲应力进行了推导分析,得到相应畸变屈曲半波长、畸变屈曲应力以及稳定系数计算公式。通过与有限条法进行对比分析,表明推导出的畸变屈曲应力计算方法具有较高的精度和较好的适用性。在此基础上,建立了冷弯薄壁型钢卷边槽形截面部分加劲板件弹性局部和畸变屈曲稳定系数的统一计算公式。最后通过算例分析,验证了该文提出方法的合理性和适用性,相对于中国现行《冷弯薄壁型钢结构技术规范》能够更加准确的计算部分加劲板件的屈曲稳定系数及卷边槽形截面构件的稳定承 载力。 相似文献
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Basis for all colculations of steel properties using metallurgical modelling is the fact that the mechanical properties are determined unambiguously by the microstructure and the chemical composition of the hot strip. Therefore it is the task of metallurgical modelling to describe the metallurgical processes which are involved in the evolution of microstructure during the rolling and cooling of hot strip as precise as possible. From the calculated microstructural parameters of the finished product in final algorithms the mechanical properties are predicted. For the production of hot strip in a hot rolling mill at TKS such a simulation system has been developed and named TKS‐StripCam. It is based mainly on semi‐physical models adapted to results from laboratory measurements. Using production parameters such as rolling schedule or as cooling conditions as well as the chemical composition as input parameters TKS‐StripCam allows one to the calculate the microstructure and to derive from this e.g. yield strength, tensile strength, elongation to fracture with sufficient precision. The principles of TKS‐StripCam will be presented. Some applications of this metallurgical simulation system with offline use in the office and online use in a hot rolling mill will be demonstrated. 相似文献
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平面度是几何量测量中的一个重要参数。测量得到的平面是利用理想平面作为基准,使其它计量器具有相应的参照平面,从而对其平面度进行评定。本文根据对角线评定方法,对平面度测量的数学模型及不确定度的评定进行了探讨。 相似文献
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Silicon steel circular blanks are often used in the manufacture of electric motors. Most factories use rectangular sheets to make these blanks, however, the silicon steel is usually produced in rolls and thus these rolls must be cut at the steelworks into sheets with user-specified lengths. An algorithm to determine the optimal sheet length is presented in this paper. It considers the sheet lengths in an ascending order, and selects the best one of them. The optimal solution for a specific length is then taken to be the initial solution of the next length. A cutting pattern usually consists of one or two segments. Strips in a segment have the same length and direction, which is either horizontal or vertical. More than one row of identical blanks can be produced from a strip. The algorithm uses dynamic programming to determine the optimal strip layouts on segments, and finds the optimal segment lengths through implicit enumeration. The computational results indicate that the algorithm is efficient both in computation time and in material usage. Finally, the solution to an example is presented. 相似文献
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带斜撑型钢-混凝土竖向混合结构是为将直接空冷技术推广应用于高强度地区而提出的一种新型结构体系,根据上部结构平台型式的不同,可分为钢桁架+斜撑结构与实腹梁+斜撑结构两种类型。本文在钢桁架+斜撑结构模型抗震试验研究的基础上,采用ABAQUS有限元软件计算分析两类结构在不同强度地震作用下的基底剪力响应规律、变形性能与钢筋混凝土管柱的损伤演化特性。结果表明:提出的模型简化原则与有限元建模方法比较合理,计算值与试验值吻合较好;不同强度地震作用下,钢桁架+斜撑结构的最大基底剪力与剪重比均大于实腹梁+斜撑结构;两类结构的侧移变形随地震作用的增强均由弯剪型趋于剪切型,钢桁架+斜撑结构的牛腿及下部位移略大于实腹梁+斜撑结构,而牛腿上部位移则略小;钢桁架+斜撑结构的最大柱顶侧移角略小于实腹梁+斜撑结构;两类结构的抗震性能均较好,能够满足大容量机组火电厂在高强度区的抗震需求。 相似文献