Variation analysis of ultimate pullout capacity of shallow horizontal strip anchor plate with 2-layer overlying soil based on nonlinear M-C failure criterion

Based on the nonlinear Mohr-Coulomb failure criterion and an associated flow rule,a kinematic admissible velocity field of failure mechanism of the 2-layer soil above a shallow horizontal strip anchor plate is constructed.The ultimate pull-out force and its corresponding failure mechanism through the upper bound limit analysis according to a variation principle are deduced.When the 2-layer overlying soil is degraded into single-layer soil,the model of ultimate pullout force could also be degraded into the model of single-layer soil.And the comparison between results of single-layer soil variation method and those calculated by rigid limit analysis method proves the correctness of our method.Based on that,the influence of changes of geotechnical parameters on ultimate pullout forces and failure mechanism of a shallow horizontal strip anchor with the 2-layer soil above are analyzed.The results show that the ultimate pull-out force and failure mechanism of a shallow horizontal strip anchor with the 2-layer soil above are affected by the nonlinear geotechnical parameters greatly.Thus,it is very important to obtain the accurate geotechnical parameters of 2-layer soil for the evaluation of the ultimate pullout capacity of the anchor plate.

Acid-pickling plates and strips speed control system by microwave heating based on self-adaptive fuzzy PID algorithm

Double self-adaptive fuzzy PID algorithm-based control strategy was proposed to construct quasi-cascade control system to control the speed of the acid-pickling process of titanium plates and strips. It is very useful in overcoming non-linear dynamic behavior, uncertain and time-varying parameters, un-modeled dynamics, and couples between the automatic turbulence control (ATC) and the automatic acid temperature control (AATC) with varying parameters during the operation process. The quasi-cascade control system of inner and outer loop self-adaptive fuzzy PID controller was built, which could effectively control the pickling speed of plates and strips. The simulated results and real application indicate that the plates and strips acid pickling speed control system has good performances of adaptively tracking the parameter variations and anti-disturbances, which ensures the match of acid pickling temperature and turbulence of flowing with acid pickling speed, improving the surface quality of plates and strips acid pickling, and energy efficiency.

Steckel mill as a green steel strip and plate production technology

The Steckel mill,a long established solution for the economical production of relatively small volumes of hot rolled strip,has been rejuvenated in recent years by a range of new applications,boosted by the need of improving the energetic efficiency of the rolling process.The traditional advantages of the Steckel mill in terms of flexibility and reduced capital and operational costs are now enhanced by technological developments that have significantly expanded its application range into the combined production of strip and plate and improved the product quality.The increased awareness of the necessity of a sustainable growth in the steel industry has stimulated the development of process solutions with an improved efficiency in the use of natural resources,lower carbon emissions and increased yield.Modern Steckel mills are an adequate response to the trend towards low energy strip and plate production,in particular in their plate-Steckel mill variant.Siemens VAI have played a key role in the innovation and transformation of the Steckel mill concept,with a number of recent installations,presented in this paper from the point of view of their contribution to the development of greener steel rolling technologies.

DYNAMIC RESPONSE OF PLATES DUE TO MOVING VEHICLES USING FINITE STRIP METHOD

Dynamic response of beam-like structures to moving vehicles has been extensively studied. However, the study on dynamic response of plates to moving vehicles has so far received but scant attention. A plate-vehicle strip for simulating the interaction between a rectangular plate and moving vehicles was described. For the portion of strips that are in direct contact with the moving vehicles, the plate-vehicle strips were employed. Conventional plate finite strips were used to model the portion of strips that are not directly under the action of moving vehicles. In the analysis, each moving vehicle is idealized as a one-foot dynamic system with tire unsprung mass and sprund mass interconnected by a spring and a dashpot. The numerical results obtained from the proposed method agree well with available results.

基于弛豫时间归一化参数的锂离子电池析锂量检测方法

析锂作为锂离子电池使用的主要安全隐患之一,不仅会造成电池的寿命极速衰减,还可能引发燃烧、爆炸等灾难性后果。随着近年来快充技术的发展,对于锂离子电池析锂情况的诊断需求愈发迫切。针对现有定量方法诊断精度严重受制于测试温度的问题,提出了一种基于弛豫时间归一化表征的改进电压释放法。从理论上分析了“析锂量与温度”因素组合对电池电压释放行为的影响规律。在此基础上,将释放阶段弛豫电压差分曲线峰值处所对应时间,与完全释放时间作比,得到“弛豫时间归一化参数”这一温度脱敏的析锂量诊断无量纲特征参数。分别利用多物理模型仿真与实验测试,验证了新方法诊断的准确性与温度适应性。

宽板连轧锥形工作辊轴向窜动调控及工业应用

为了提高连轧锥形工作辊轴向窜动控制精度,对材料加工时发生横向流动的过程建立有限元模型,并构建了机架轧后屈服模型,并将模型置于现场环境中开展验证研究。研究结果表明:受到轧后屈服作用时,处于边降区(15~115)mm之间的断面误差可以控制到3μm范围内,与带钢边部的最大偏差在(0~15)mm之间。在机架间和轧制区内都出现了横向流动的情况,导致锥形辊发生了边降调控性能下降。随着窜辊量增大后,第一、二机架都出现功效下降的结果,第三机架则持续增大至最高功效。下游机架窜辊位都位于上游机架控制特征点范围内。这里调控方式形成了显著边部效果,可以观察到内部偏差。该研究对保证板材的轧制质量具有很好的实际指导价值。

引线框架用高性能铜合金板带材及制备工艺

电子信息产业的飞速发展,对铜及铜合金产品性能提出了更高的要求,其中集成电路封装用引线框架材料代表了铜合金板带材发展的较高水平。本文对近年来引线框架用高性能铜合金板带材及制备工艺进行了综述,介绍了国内外高性能铜合金板带材料的成分和制备加工技术及发展过程,并对其未来发展趋势进行了展望,提出未来高性能铜板带材性能将朝着抗拉强度为700 MPa、导电率为70%IACS的目标发展,其制备工艺将向着智能化、绿色化、高效化等方向发展。

热浸镀锡电子铜带材回流焊过程中镀锡层的微观结构及缺陷分析

热浸镀锡电子铜带材是高端连接器和PCB(Printed circuit board)所需的关键导体材料,该材料在回流焊过程中产生的缺陷严重影响其服役性能。采用扫描电镜(SEM)、能谱仪(EDS)对热浸镀锡铜带材回流焊过程中缺陷组织类型及分布形态进行表征,并对回流焊锡珠样品、回流焊非正常样品和回流焊正常样品的表层形貌进行对比。结果表明:回流焊过程中,样品镀层中均产生了不同程度的孔洞缺陷,孔洞尺寸在0.2~36μm,孔洞的产生与基体合金类型、基体合金厚度和镀层厚度无明显关联;孔洞形态并不一致,发现了孔洞边缘呈现出立体网状结构、边缘参差不齐、孔洞中存在小颗粒的现象。回流焊过程中,镀锡层中Cu、Sn元素发生了重新分布,不同缺陷所造成的元素分布情况并不相同。镀层结构中,化合物层、多相界面间高低起伏与镀层表面高度起伏无明显关联。

Excitation and Detection of Shear Horizontal Waves with Electromagnetic Acoustic Transducers for Nondestructive Testing of Plates

The fundamental shear horizontal（SH0） wave has several unique features that are attractive for long-range nondestructive testing（NDT）. By a careful design of the geometric configuration, electromagnetic acoustic transducers（EMATs） have the capability to generate a wide range of guided wave modes, such as Lamb waves and shear-horizontal（SH） waves in plates. However, the performance of EMATs is influenced by their parameters. To evaluate the performance of periodic permanent magnet（PPM） EMATs, a distributed-line-source model is developed to calculate the angular acoustic field cross-section in the far-field. Numerical analysis is conducted to investigate the performance of such EMATs with different geometric parameters, such as period and number of magnet arrays, and inner and outer coil widths. Such parameters have a great influence on the directivity of the generated SH0 waves that arises mainly in the amplitude and width of both main and side lobes. According to the numerical analysis, these parameters are optimized to obtain better directivity. Optimized PPM EMATs are designed and used for NDT of strip plates. Experimental results show that the lateral boundary of the strip plate has no perceivable influence on SHO-wave propagation, thus validating their used in NDT. The proposed model predicts the radiation pattern ofPPM EMATs, and can be used for their parameter optimization.

超高性能混凝土板加固足尺钢筋混凝土梁抗剪性能

为进一步研究超高性能混凝土(ultra-high-performance concrete,UHPC)预制板加固钢筋混凝土(reinforced concrete,RC)梁的抗剪性能,开展了3根足尺RC梁的试验研究,包含1根对比梁和2根UHPC预制板加固梁,关注UHPC板及其内嵌CFRP板条对RC梁抗剪性能的影响。试验结果表明:试验梁均发生受剪破坏,但加固梁的承载力、刚度和延性均明显提高,其中,因内嵌CFRP板条提高了UHPC板的抗裂性能,极限荷载及对应位移分别提高了30.8%和28.5%;螺杆力学锚固发挥了侧向约束作用和销栓作用,在一定程度上提高了UHPC板的贡献。同时,通过建立非线性有限元模型对试验梁进行了数值分析,模拟结果与试验结果吻合度高,表明模型所选的本构关系及相关参数合理,可用于预测UHPC板加固RC梁的全过程受力行为。

一种高精度四辊板带材轧机支撑辊偏心辨识的研究

板带轧机中上下支撑辊偏心信号是较为典型的一种频率相近的周期波,如果仍采用传统的快速傅立叶变换(FFT)辨识该偏心信号就很难保证结果的精准性与可靠性。对此,在本课题中,笔者经过广泛且深入地探索与研究推出了可有效解决此问题的新辨识方法,即最小二乘法(LS),该算法的实现过程依托经典且成熟的观测矩阵理论,利用2范数最小的终止准则完成求解操作,并从中确定出最相近的特征参数。算例计算结果显示:当上下支撑辊的频率差为和,FFT所辨识的幅值和相角均严重失真,而LS方法所辨识的幅值精度分别可达0.064%和0.127%,相角的辨识精度分别为0.076%和0.0286%。同时利用某四机架板带连轧生产的实际采集的轧制力数据作为辨识目标,通过分析各个机架的轧辊偏心的影响,可以看出在246Hz处的轧辊偏心信号被很好地辨识。因此笔者提出的这种新方法可提供准确、可靠的辨识结果,而且不容易受外部干扰,进而从源头上提高了识别效率,保证了识别的精准度。

A new method for evaluating wedges of steel plates and strips

To overcome the inaccuracy problem of the traditional wedge evaluation of steel plates and strips caused by the ran-domness of the thicknesses of two local points and improve the reliability of the wedge index,the double-centroid method for the wedge evaluation was proposed,and a model based on the centroid theory was established.Meanwhile,an integral model for the discrete thickness values of the cross-section profiles was derived.The discussion focused on the distinct characteristics of the two-point method,asymmetric method,and double-centroid method in evaluating the asymmetric distribution of cross-sections.The three methods were employed to evaluate the wedge values of both the theoretical and measured cross-sections of steel plates and strips,and the accuracies of three wedge evaluation models were analyzed and discussed.The results showed that the double-centroid method objectively reflects the degree and variation characteristics of the wedge values of the cross-sections of steel plates and strips,and this method is feasible,reliable,and outstanding.

Interfacial chemistry of anode/electrolyte interface for rechargeable magnesium batteries

Rechargeable magnesium batteries(RMBs),as a low-cost,high-safety and high-energy storage technology,have attracted tremendous attention in large-scale energy storage applications.However,the key anode/electrolyte interfacial issues,including surface passivation,uneven Mg plating/stripping,and pulverization after cycling still result in a large overpotential,short cycling life,poor power density,and possible safety hazards of cells,severely impeding the commercial development of RMBs.In this review,a concise overview of recently advanced strategies to address these anode/electroyte interfacial issues is systematically classified and summarized.The design of magnesiophilic substrates,construction of artificial SEI layers,and modification of electrolyte are important and effective strategies to improve the uniformity/kinetics of Mg plating/stripping and achieve the stable anode/electrolyte interface.The key opportunities and challenges in this field are advisedly put forward,and the insights into future directions for stabilizing Mg metal anodes and the anode/electrolyte interface are highlighted.This review provides important references fordeveloping the high-performance and high-safety RMBs.

Self-Adaptive and Electric Field-Driven Protective Layer with Anchored Lithium Deposition Enable Stable Lithium Metal Anode

Lithium metal battery has great development potential because of its lowest electrochemical potential and highest theoretical capacity.However,the uneven deposition of Li^(+)flux in the process of deposition and stripping induces the vigorous growth of lithium dendrites,which results in severely battery performance degradation and serious safety hazards.Here,the tetragonal BaTiO3 polarized by high voltage corona was used to build an artificial protective layer with uniform positive polarization direction,which enables uniform Li^(+)flux.In contrast to traditional strategies of using protective layer,which can guide the uniform deposition of lithium metal.The ferroelectric protective layer can accurately anchor the Li^(+)and achieve bottom deposition of lithium due to the automatic adjustment of the electric field.Simultaneously,the huge volume changes caused by Li^(+)migration change of the lithium metal anode during charging and discharging is functioned to excite the piezoelectric effect of the protective layer,and achieve seamless dynamic tuning of lithium deposition/stripping.This dynamic effect can accurately anchor and capture Li^(+).Finally,the layer-modified Li anode enables reversible Li plating/stripping over 1500 h at 1 mA cm^(-2)and 50℃in symmetric cells.In addition,the assembled Li-S full cell exhibits over 300 cycles with N/P≈1.35.This work provides a new perspective on the uniform Li^(+)flux at the Li-anode interface of the artificial protective layer.

自动化剥锌设备极板自动接驳移载系统的设计

自动化剥锌设备极板自动接驳移载系统是湿法锌冶炼锌片自动剥离系统的关键设备,用于对输入和输出自动化剥锌设备的极板进行接收、存储、等间距排列、移载,实现极板在自动化剥锌设备与电解槽之间的转运。通过对自动化剥锌设备工作流程、现有结构、性能要求进行综合分析,对自动化剥锌设备极板自动接驳移载系统进行了设计,具体包括极板接驳装置、极板链条输送装置、极板放置装置、驱动系统、电气系统、控制系统等。现场应用表明,所设计的自动化剥锌设备极板自动接驳移载系统实现了极板在天车和自动化剥锌设备间的高效、稳定、快速转运,不需要人工辅助作业,为智能化无人剥锌打下了基础。

土质斜坡地层倾斜锚板抗拔承载力分析

研究目的:合理估算锚板抗拔承载力是保持锚板基础稳定工作的重要保障,本文聚焦土质斜坡地层中埋设的倾斜条形锚板,构造了一种极限状态下非对称的锚板上拔破坏机制,并假设土体破坏服从非线性强度准则与非关联流动法则。基于该破坏机制,利用上限法与变分原理,推导锚板极限抗拔承载力及锚板上方土体破坏面方程的解析表达式,系统研究各参数对锚板抗拔承载力的影响规律。研究结论:(1)推导得到了锚板极限抗拔承载力及锚板上方土体破坏面方程的解析表达式,并与现有文献成果进行了对比分析,验证了本文分析方法的有效性;(2)斜坡倾斜锚板上方土体破坏范围呈现一定的非对称特征,随锚板倾角增大,土体破坏范围逐渐向坡下方向偏移,土体破坏范围与土体剪胀系数、初始黏聚力正相关,与非线性系数、重度、地表荷载负相关;(3)锚板埋深比、埋设角度、地表倾角、土体黏聚力及剪胀系数对锚板抗拔承载力及土体上拔破坏范围会产生显著影响,在工程设计中应予以重视,以实现锚板基础的最优布设与承载能力有效发挥。

汽提塔的选型和安装对PVC树脂质量的影响

详细介绍了筛板式汽提塔和溢流式筛板汽提塔的结构、设计参数和安装要点,探讨了汽提塔安装精度对PVC树脂质量的影响。

基于BP神经网络的板带轧机液压HGC状态监测方法

提出了一种基于BP神经网络的板带轧机液压HGC状态监测方法,利用BP神经网络算法进行模型训练和状态识别。通过对历史数据的分析和学习,建立了液压HGC状态与传感器数据之间的映射关系。然后,利用训练好的神经网络模型对实时数据进行监测和预测,从而实现对液压HGC系统状态的实时监测和故障预警。该方法能够准确监测液压HGC系统的状态,并提供及时的预警信息,为轧机运行维护和产品质量提升提供了有效的支持。

膨胀剂和后浇带对超长环形底板混凝土防裂的影响研究

世界上亮度最高的第四代高能同步辐射光源的超长环形底板周长约1494 m、厚1 m,如何保证底板混凝土施工质量防止裂缝产生是工程的难点。建立有限元三维数值分析模型,按照实际施工过程仿真底板混凝土的跳仓浇筑过程,模拟分析底板混凝土温度及温度应力变化情况,同时将计算温度结果与实测温度结果进行对比,验证热学参数的合理性和准确性。在反演分析基础上,研究膨胀剂和后浇带的温控防裂效果。研究结果表明:早膨胀型自变(Ⅰ型)对混凝土早龄期应力的影响是有利的,但晚膨胀型自变(Ⅲ型)的延迟膨胀性补偿由于混凝土收缩和温降引起的应力,有利于减小底板冬季最大拉应力;设置后浇带能减小底板混凝土分缝分块长度,削减混凝土最大拉应力,削减幅度为6.65%。

GB/T713—2014与GB/T713—2023标准的比较和分析

GB/T 713—2023《承压设备用钢板和钢带》于2023年8月6日发布,于2024年3月1日实施。对GB/T 713—2023和GB/T 713—2014标准进行了对比,介绍了GB/T 713—2023标准的主要修订情况,并对新标准的新要点进行分析,可为承压设备设计单位、制造单位及设计人员在应用新标准过程中提供参考。