钢水包坠落事故分析

１　事故经过　　１９９８年５月，某钢厂铸钢车间的１００ｔ桥式起重机起吊重约１０ｔ的钢水包，采用上升第二挡慢速上升。当钢水包到达距预定位置还有１００ｍｍ左右时，钢水包突然急速下落，操作者还未反应过来，钢水包已落到地面。落地震动使钢水溢出，热浪使安全滑线变形，幸好未造成人员伤亡。２　原因分析　　我们认真检查了上升接触器的线圈回路，发现上升接触器线圈接线端子上的导线已脱落。接线端子的导线是采用螺母固定的，此时螺母松动，导线已悬空。可见，起升机构在上升方向启动时，接线端子的导线并未脱落，而是在上升过程中…     

钢水包滑动系统漏钢原因分析及预防

阐述钢水包滑动系统工作原理,分析钢水包滑动系统漏钢原因,提出注意事项及预防措施。     

基于Ansys的钢水包倾翻力矩研究

应用Ansys软件对钢水包在倾翻过程中的总质量、质心、转动惯量、倾翻力矩等倾翻特性随倾翻角度的变化进行分析研究,利用最小二乘法对倾翻力矩和倾翻角度进行数字拟合,得出当倾翻角度为50°时,倾翻力矩为最大值54 254 N·m。该方法对钢水包结构及倾翻电动执行机构设计具有重要工程应用价值。     

S0910 轴承测振仪轴向加载部件的力学模型

本文建立了Ｓ０９１０轴承测振仪轴向加载部件的力学模型，并进行了数学推导，为轴承测振仪轴向加载部件的性能分析提供了理论依据。     

S0910轴承测振义轴向加载部件的力学模型

本文建立了Ｓ０９１轴承测振仪轴向加载部件的力学模型，并进行了数学推导，为轴承测振仪轴向加载部件的性能分析提供了理论依据。     

一种基于电容加载环形谐振器的可调谐滤波器

为了实现多频段射频信号的同时处理,提出了一种基于电容加载环形谐振器的双频可调谐带通滤波器。在对环形谐振器等效电路进行分析的基础上给出了可变电容加载的环形谐振器结构形式,实现了对谐振频率的调谐;然后对可调滤波器的端口电抗特性进行了分析,设计了实现双频可调谐滤波器;最后设计加工了工作于330~400 MHz之间的双频可调谐滤波器,两个通频带之间可以独立调谐,并且通带互相之间的影响很小。     

ANSYS在计算钢水包倾翻特性中的应用

以钢水包为例,提出了一种运用ANSYS软件对冶金容器倾翻特性进行分析计算的方法,得出了倾翻过程中质心、转动惯量、转动力矩的变化情况以及钢水包的出水角度等数据.同时,还可以对得到的模型进行有限元分析.     

基于小波能量和RBF网络的钢水下渣自动检测

由于采用振动监测的方法进行钢水连铸下渣检测时,通常在整个频段上很难获得钢水下渣这一突变信号。提出了一种基于小波能量和RBF神经网络相结合的钢水连铸下渣的自动检测方法。首先,利用小波包分析的高时频分辨特性将振动信号分解到各个频带上,并以各频带信号的能量来构造用于下渣检测的特征参数。然后,利用RBF神经网络实现正常浇铸和下渣信号的自动识别。实验表明,该方法可有效地进行下渣的自动检测。     

基于模型参考自适应控制的力协调加载系统

本文针对力协调加载系统的特点,提出了模型参考自适应控制系统的设计方法,并阐述了系统结构及工作原理,软件设计及控制算法。为提高加载系统控制精度和加载速度,在系统结构设计过程中,分别设计了应变放大器和双恒流源等电路,并采用了智能接口和双机通讯技术,软件设计具有模块化,结构化等特点。加载试验证明了控制方法的可行性。     

EPS疲劳试验转矩加载模型分析

目前EPS(电动助力转向系统)越来越多地应用在汽车中,因此对其寿命的估计就变得尤为重要。EPS测试系统主要分为两部分,分别为转矩加载部分和中间轴末端振动加载部分。针对前者,先进行转矩加载来源分析,并在此基础上搭建其动力学模型,再根据建模给出扭矩疲劳测试台的动力学描述,这将成为后续理论计算的根据,更好地为试验台的搭建提供理论基础,具有一定的实际意义。     

钢包回转台提升梁的焊接

通过对蝶式钢包回转台提升梁材料Q345B-Z15厚板焊接工艺分析,以及提升梁焊装难点、重点详细分析,采取了一些新型实用的方法,并阐述了该方法的要点。通过实际制作证明,采用此方法确保产品质量,降低了制造成本,缩短生产工期,为类似大型焊接件焊装积累宝贵经验。     

Improving the accuracy of Laplacian estimation with novel multipolar concentric ring electrodes

Conventional electroencephalography with disc electrodes has major drawbacks including poor spatial resolution, selectivity and low signal-to-noise ratio that are critically limiting its use. Concentric ring electrodes, consisting of several elements including the central disc and a number of concentric rings, are a promising alternative with potential to improve all of the aforementioned aspects significantly. In our previous work, the tripolar concentric ring electrode was successfully used in a wide range of applications demonstrating its superiority to conventional disc electrode, in particular, in accuracy of Laplacian estimation. This paper takes the next step toward further improving the Laplacian estimation with novel multipolar concentric ring electrodes by completing and validating a general approach to estimation of the Laplacian for an (n + 1)-polar electrode with n rings using the (4n + 1)-point method for n ⩾ 2 that allows cancellation of all the truncation terms up to the order of 2n. An explicit formula based on inversion of a square Vandermonde matrix is derived to make computation of multipolar Laplacian more efficient. To confirm the analytic result of the accuracy of Laplacian estimate increasing with the increase of n and to assess the significance of this gain in accuracy for practical applications finite element method model analysis has been performed. Multipolar concentric ring electrode configurations with n ranging from 1 ring (bipolar electrode configuration) to 6 rings (septapolar electrode configuration) were directly compared and obtained results suggest the significance of the increase in Laplacian accuracy caused by increase of n.     

Frequencies of circular plate with concentric ring and elastic edge support

Exact solutions for the flexural vibrations of circular plates having elastic edge conditions along with rigid concentric ring support have been presented in this paper. Values of frequency parameter for the considered circular plate are computed for different sets of values of elastic rotational and translation restraints and the radius of internal rigid ring support. The results for the first three modes of plate vibrations are computed and are presented in tabular form. The effects of rotational and linear restraints and the radius of the rigid ring support on the vibration behavior of circular plates are studied over a wide range of non-dimensional parametric values. The values of the exact frequency parameter presented in this paper for varying values of restraint parameters and the radius of the rigid ring support can better serve in design and as benchmark solutions to validate the numerical methods obtained by using other methods of solution.     

Vibration of circular Mindlin plates with concentric elastic ring supports

This paper studies the vibration behaviour of circular Mindlin plates with multiple concentric elastic ring supports. Utilizing the domain decomposition technique, a circular plate is divided into several annular segments and one core circular segment at the locations of the elastic ring supports. The governing differential equations and the solutions of these equations are presented for the annular and circular segments based on the Mindlin-plate theory. A homogenous equation system that governs the vibration of circular Mindlin plates with elastic ring supports is derived by imposing the essential and natural boundary and segment interface conditions. The first-known exact vibration frequencies for circular Mindlin plates with multiple concentric elastic ring supports are obtained and the modal shapes of displacement fields and stress resultants for several selected cases are presented. The influence of the elastic ring support stiffness, locations, plate boundary conditions and plate thickness ratios on the vibration behaviour of circular plates is discussed.     

GD20型飞机悬挂物挂装车举升机构的设计与有限元分析

以GD20型飞机悬挂物挂装车举升机构为研究对象,设计了满足功能要求的举升机构,对举升机构的主要承力构件举升臂进行了详细的受力分析与计算,在此基础上,对举升臂进行了结构设计,并对其最低位置、水平位置和最高位置3个工位的受力状态进行了有限元分析,验证了零件结构满足强度设计要求。     

三轴激光陀螺温度误差动态建模及补偿技术

提出了一种新的三轴激光陀螺温度误差动态建模及测试方案,并进行了实验。实验结果表明,新的动态模型能够对大变温率、大范围温变条件下陀螺的漂移进行有效补偿,且补偿后陀螺精度在全温度范围内优于0.05 °/h 。与静态模型相比,动态建模方法具有测试时间短、模型精度高及易于工程实现等优点。     

新型环式减速器动态特性分析

根据一种新型环式减速器内的结构,利用ABQUS建立了有限元模型,并针对该减速器进行了模态分析,获得了内齿环板的振动频率及相应的振型特征;然后,进行了动力学稳态响应分析。为下一步进行新型环式减速器的改进及优化设计提供了可靠的依据。     

推力轴承套圈平面磨削方法浅析

对两种推力套圈平面磨削方法进行了分析,指出其加工特点、精度、效率和适用范围。     

Analysis of retaining ring using finite element simulation in chemical mechanical polishing process

During the chemical mechanical polishing process (i.e., CMP for short), it is expected to attain the requirement of global planarization. However, the stress concentration, which occurred when approaching the wafer edge, has resulted in over-grinding. The increasing material removal rate has also contributed to the wafer’s nonuniformity. In this paper, a retaining ring surrounding the wafer carrier was added to the conventional CMP mechanism in order to improve the over-grinding phenomenon and avoid the wafer sliding from the carrier as much as possible. The revolutions of the wafer and the pad were assumed to be the same, and the force forms of the carrier and the retaining ring were axisymmetric uniformly-distributed. In addition, when the principle of minimum potential energy was applied, a two-dimensional axisymmetric quasi-static finite element model for CMP including the carrier, the retaining ring, the film, the wafer and the pad could be established. Following this model, the von Mises stress distribution of the wafer surface without a retaining ring was analyzed to verify the model. The effects of the gap between the ring and the pad and the ratio of the ring load and the carrier load on the stress and the wafer’s nonuniformity were investigated. The results indicated that the von Mises stress distribution of the wafer surface was almost uniform near the wafer center, and the maximum value appeared near the edge. The value decreased as the edge was approached, but it rose again very close to the edge. Besides, the wafer’s nonuniformity would be prohibited while the gap and the load were designed within the certain range to supply the retaining ring.     

Fundamental buckling of circular plates with elastically restrained edges and resting on concentric rigid ring support

This work presents the existence of buckling mode switching with respect to the radius of concentric rigid ring support. The buckling mode may not be axisymmetric as previously assumed. In general, the plate may buckle in an axisymmetric mode but when the radius of the ring support becomes small, the plate may buckle in an asymmetric mode. The optimum radius of the concentric rigid ring support for maximum buckling load is also determined. Introducing internal rigid ring support, when placed at an optimal position increases the elastic buckling load capacity by 149.39 percent. The numerical results obtained are in good agreement with the previously published data.