重轨水平矫直规程对矫后残余应力的影响

建立了具有原始曲率的60kg/m重轨九辊水平矫直有限元模型,应用显式动力学软件ANSYS/LS-DYNA对矫直过程进行了数值模拟,对不同矫直规程矫后重轨残余应力的大小和分布状态进行了研究,得到了各辊压下量对残余应力的影响规律,对提高重轨矫直质量和矫直规程的制定具有参考价值.     

重轨复合矫直参数控制模型

作为重轨生产中最后变形工艺,矫直对提高重轨质量、提高成材率等具有重要意义.按照重轨生产的需要,建立了重轨平立复合矫参数控制模型,模型包括结构参数模型、力能参数模型、工艺参数模型、平直度模型,对重轨的矫直工艺进行控制,如果工艺参数不能满足要求,再由自学习模型和应力应变模型通过智能学习数据库中历史数据参数相互关系,给出优化的调整值.模型不仅实现了对复合矫直工艺的控制,也很好满足了企业对多规格重轨工艺参数的控制需求.     

大型H型钢矫直规程对矫后残余应力的影响分析

通过现场数据采集和实验研究,建立了规格为HN1000X300的最大型H型钢九辊平行辊矫直实体模型和有限元模型,把模型导入Workbench LS-DYNA显示动力学软件模块中,进行材料参数、网格划分、初始条件及边界条件设置并计算,成功的完成了大型H型钢HN1000x300在现场生产矫直规程及不同矫直规程下进行的矫直过程数值模拟,对各矫直规程下的矫后残余应力大小和分布规律统计对比分析,得出矫后残余应力值最小且分布状态合理的最佳矫直规程,最佳矫直规程的设定对提高矫直质量和生产率具有十分重要的意义。     

拉弯矫直延伸率的计算及试验分析

针对目前拉弯矫直过程缺少完整的数学求解模型的问题,根据矫直带材在拉弯过程中,中性层偏移量及延伸率的计算模型,给出了拉弯矫直张力、矫直力和延伸率的计算方法。通过计算与工业试验,分析了拉弯矫直机矫直规程对残余延伸率的影响,并验证了计算模型的精确性。     

新型钢轨矫直机

针对传统重轨矫直机在使用中暴露出来的问题,构想了新型钢轨矫直机,有重量轻、易维护、矫直质量高等优点。     

新型钢轨矫直机

针对传统重轨矫直机在使用中暴露出来的问题,构想了新型钢轨矫直机,有重量轻、易维护、矫直质量高等优点.     

新型钢轨矫直机

针对传统重轨矫直机在使用中暴露出来的问题，构想了新型钢轨矫直机，有重量轻、易维护、矫直质量高等优点。     

中厚板矫直机的压下规程对矫直精度的影响模拟分析

针对实践需求及存在问题,在大变形矫直原理的基础上,对某公司改进设计后的九辊中厚板辊式矫直机,建立了矫直辊压下量的数学模型。并采用LS-DYNA软件对40 mm厚度的Q345中厚板模拟矫直过程,通过分析矫后板材残余应力及板形平直度的变化情况,研究矫直辊的压下规程对中厚板矫直精度的影响。结果表明:矫后中厚板纵向上的残余应力最大、厚度方向上的残余应力最小;合理地矫直辊的压下规程,不仅可以使矫后板材的残余应力最小,还能明显地改善板材的平直度。     

横切机组矫直过程板形变化机理及其预报模型

充分考虑横切矫直机组设备和工艺特点,对矫直机组成品板形的变化机理进行了分析,并在此基础上进行了试验研究,探究矫直辊系对板形的影响,得出矫直机组的矫直过程是通过对带钢的多次弯曲拉直实现的;对试验数据分析处理后,进行带钢所受矫直辊的压应力和摩擦力求解,得出矫直过程板形变化数学模型,从而建立了一套完整的适合横切机组矫直过程的板形预报模型。在此基础上编制了相应的横切机组矫直过程板形预报软件,该软件能够快速求出矫直后带钢的板形分布。将软件应用到某1220横切机组的生产实践,可以明显地看出矫直后带钢的板形计算值和实测值几乎相等,板形预报结果符合现场生产实际。     

薄壁管材矫直曲率半径数学模型及其验证

矫直曲率半径作为矫直工序的核心工艺参数,对管材特别是薄壁管材的矫直精度起到决定性作用。而目前在薄壁管材的矫直生产中,仍然沿用经典理论的数据图表,结合人工经验和反复试矫对其进行估定,亟待建立精确的矫直曲率半径数学模型以指导生产,为此基于薄壳构件弹塑性理论及其相关假设建立了针对薄壁管材矫直变形区的应力应变关系模型,进而对变形区弯曲力矩进行解析,运用经典卸载规律建立薄壁管材矫直曲率半径的数学模型方程,同时给出求解方法。通过有限元仿真分析和现场试验,并与经典矫直理论的计算结果进行对比,证明该模型在处理薄壁管材矫直问题时是正确和有效的,为继续深入研究矫直相关工艺参数的合理设置、完善薄壁管材矫直理论体系奠定基础。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.