楔形工形柱平面内稳定极限承载力研究

通过对12根楔形柱进行静态加载试验,分析和研究楔率及偏心距对楔形柱平面内极限承载力的影响.试件的主要参数为荷载作用的偏心距和楔率.试验在5 000 kN试验机上进行,主要测量了型钢的纵向应变、试件的变形过程、荷载-挠度曲线及试件的极限承载力.试验结果表明,随着楔率的增大,构件的极限承载力也随之增加;荷载偏心距的增大将降低构件的极限承载力.     

电磁轴承电气系统可靠性分析

为了提高电磁轴承的可靠性,对电磁轴承的电气系统进行了分析,绘制了可靠性框图,针对乙烯制冷压缩机中的电磁轴承的可靠性进行了计算,提出了电磁轴承电气系统中各组件的可靠性技术要求,并对故障原因及其影响作了分析,提出了提高电磁轴承可靠性的方法.     

Intelligent fault diagnosis for rolling bearings based on graph shift regularization with directed graphs

Graph shift regularization is a new and effective graph-based semi-supervised classification method, but its performance is closely related to the representation graphs. Since directed graphs can convey more information about the relationship between vertices than undirected graphs, an intelligent method called graph shift regularization with directed graphs (GSR-D) is presented for fault diagnosis of rolling bearings. For greatly improving the diagnosis performance of GSR-D, a directed and weighted k-nearest neighbor graph is first constructed by treating each sample (i.e., each vibration signal segment) as a vertex, in which the similarity between samples is measured by cosine distance instead of the commonly used Euclidean distance, and the edge weights are also defined by cosine distance instead of the commonly used heat kernel. Then, the labels of samples are considered as the graph signals indexed by the vertices of the representation graph. Finally, the states of unlabeled samples are predicted by finding a graph signal that has minimal total variation and satisfies the constraint given by labeled samples as much as possible. Experimental results indicate that GSR-D is better and more stable than the standard convolutional neural network and support vector machine in rolling bearing fault diagnosis, and GSR-D only has two tuning parameters with certain robustness.     

国家自然科学基金项目（51769017、51969018）

针对现有碾压混凝土坝温度场预警多是基于单个测点进行分析这一不足,提出了利用多测点综合信息预警的模式和方法。采用概率原理对温度监测值的有序度和无序度进行了定义,基于投影追踪法,确定了各测点的权重分布;根据温度场有序到无序的演变规律,结合有序度和测点权重分布,构建了能描述碾压混凝土坝温度场有序性的权重熵;借助典型小概率原理,提出了碾压混凝土坝温度场预警准则。实例分析表明：权重熵的变化规律与温度实测值变化规律相吻合,从而验证了该方法的可行性和有效性。     

高温气候下沥青混凝土心墙连续碾压施工结合面温控试验研究

在夏季高温气候沥青混凝土心墙连续多层施工时,为减少等待结合面温度降至规范要求上限值90℃的时间,通过室内试验模拟结合面温度提高后心墙连续两层铺筑的情况,分别研究了结合面温度在90℃、100℃、110℃情况下沥青混凝土的压实性和变形情况,并进行了现场试验论证。室内试验结果表明:心墙沥青混凝土结合面温度降至100℃时,上层沥青混凝土的孔隙率为2.88%,下层沥青混凝土的最大侧向应变值为2.78%;结合面温度为110℃时,上层沥青混凝土的孔隙率为3.85%,下层沥青混凝土的最大侧向应变值为4.00%。现场试验结果表明:结合面温度为100℃时的上层沥青混凝土孔隙率和渗透系数均满足规范要求。因此,沥青混凝土心墙连续多层碾压时,结合面温度提高至100℃的施工质量可以得到保证。     

Characteristics of Left-Right Spiral Hollow Cylindrical Roller

Based on new rolling-sliding compound bearings,the wear between the one-way spiral hollow cylindrical roller and the ribs of the inner and outer ring of rolling-sliding compound bearings is reduced by innovational structural design. A new left-right spiral hollow cylindrical roller is proposed to replace the one-way spiral hollow cylindrical roller. The finite element analysis models of ordinary cylindrical rollers,one-way spiral hollow cylindrical rollers and left-right spiral hollow cylindrical rollers are respectively established by ABAQUS.The axial displacement of their center mass and the stress distribution of left-right spiral hollow cylindrical rollers are compared and analyzed. Theoretical study results show that this new left-right spiral hollow cylindrical roller not only inherits the advantages of one-way spiral hollow cylindrical rollers,but also avoids the axial offset and the serious wear of the one-way spiral hollow cylindrical roller. And the theory research conclusion is verified by the experiment. The left-right spiral hollow cylindrical roller has the advantages to overcome boundary stress concentration like logarithmic convex roller. The rolling-sliding compound bearings equipped with the new rollers can be better to adapt to the impact of vibration load.     

江垭水电站碾压混凝土重力坝的温度应力分析

为研究温度荷载对江垭水电站碾压混凝土重力坝的影响,以其非溢流坝段为研究对象,建立有限元模型,根据江垭水电站的水温、气温、坝体温度、地基温度等监测资料,计算分析了大坝运行期的温度场,研究了大坝在温度场影响下的应力变化规律.研究结果表明:温度荷载对大坝运行有较大影响,但是大坝仍满足规范设计要求;夏季持续高温时,应避免大坝在高水位下运行;冬季持续低温时,应避免大坝在低水位下运行.     

接触角螺旋升角对滚柱丝杠副传递效率的影响

建立行星滚柱丝杠副的传递效率数学模型,对行星滚柱丝杠副的正传递效率进行研究,并对传动效率影响较大的接触角和螺旋升角进行定量定性的分析,得出了螺旋升角最优值为5°,接触角45°为最佳值,为行星滚柱丝杠副的结构参数优化及产品系列化设计提供参考。     

镀锡K板板面烧蚀缺陷形成机理研究

宝钢在生产K板过程中,在高锡层面易产生针尖状烧蚀缺陷．本文通过扫描电镜和光学轮廓仪观察了其微观形貌,应用能谱仪分析了烧蚀内部成分,并分析了缺陷的产生原因．结果表明,烧蚀呈火山口形貌,大小为0．2～0．6mm．其产生是由于带钢与软熔接地辊辊面接触不良引发局部大电流电弧放电,导致带钢局部温度急剧升高,引起板面锡层熔化而形成的．提出了预防该缺陷的措施：保持软熔接地辊辊面及淬水槽溶液清洁,并在软熔接地辊前增加热风喷吹装置．将上述措施应用于实际生产中,避免了镀锡K板板面烧蚀缺陷的产生．     

9Cr3Mo冷轧辊钢的热处理

采用分析对比的方法，研究了９Ｃｒ３Ｍｏ钢与制造冷轧辊常规用９Ｃｒ２Ｍｏ钢在热处理制度、金相组织和力学性能诸方面的异同，为开发９Ｃｒ３Ｍｏ冷轧工作辊，制定合理的热处理工艺奠定了基础。