基于ANSYS的铁路客车车体结构参数化研究

根据我国通用铁路客车车体钢结构的特点,基于大型有限元分析软件ANSYS,应用参数化程序设计语言APDL对铁路客车车体进行参数化建模,并采用TCL/TK语言为界面二次开发语言,实现ANSYS内部参数与对话框输入参数间的相互传递,更好地适应了人机交互。通过对话框调整车体结构相应参数,便可自动生成车体钢结构几何模型,大大缩短了设计周期,提高了设计效率,为后续快速进行有限元分析奠定了基础。     

基于构件的高速列车车体有限元模型快速生成

高速列车车体属于典型骨架型结构产品.在高速列车车体方案设计阶段为了快速实现设计模型和有限元模型的生成和修改,提出一种基于构件理论的车体快速设计体系.研究了车体零件的定位关系,对车体零件提取构件,应用知识工程和强力拷贝技术建立自顶向下的车体三维模型;并应用车体定位装配关系生成硬点硬线,将三维模型几何数据与来自零件的关联知识通过算法自动生成车体有限元模型,实现车体三维设计模型和有限元仿真模型的快速迭代设计.     

高速列车有限元参数化

铁路车辆的性能一直都是运输行业的重要课题,对于车辆的研究会影响到整个铁路交通的发展。将列车车体分成底架、侧墙、车顶等几个模块,每个模块都有自己的子模块,将车体结构模块细化到钢板、槽钢等板材结构,用有限元软件ANSYS的参数化语言APDL语言,对车体模型以命令流的形式表示,最终达到对车体结构模型参数化,方便车体结构优化,有利于对车体进行有限元仿真分析,提高车体建模分析效率,缩短车体技术更新时间,并且有助于技术交流。     

铁路客车车体轻量化问题的研究

在车辆轻量化的过程中,车体承载结构的轻量化显得尤为重要。车体承载结构的轻量化,要保证车体的强度、刚度和动态特性等满足提速客车的要求。文中利用ANSYS软件建立25K型硬卧客车车体轻量化前后的有限元模型,计算车体的强度、刚度和模态,并对轻量化前后的车体作对比分析;然后,用NUCARS动力学分析软件建立25K型硬卧客车系统的数学模型,分析弹性振动对平稳性的影响,并就刚性车体模型和轻量化前后的弹性车体模型对平稳性和加速度响应的影响作对比分析。     

基于刚体预处理的客车侧翻安全性建模方法研究

将侧翻安全性仿真过程中客车模型的翻转、跌落阶段作为刚体绕定轴的转动过程处理,基于该假设进行了客车模型与地面的碰撞初始条件的分析计算,并通过修改原始侧翻有限元模型生成了碰撞阶段的侧翻有限元模型。基于方法对某型号全承载大客车进行了碰撞阶段的侧翻安全性仿真,验证了建模方法的可行性及高效性,并根据仿真结果对客车上部封闭杆系结构进行改进设计,提高了该车型上部结构的安全性。     

基于NX的航空发动机测试受感部参数化设计

为了缩短航空发动机测试受感部的设计周期,提出了参数化设计方法。基于结构尺寸参数化,采用NX表达式建模方式,构建不同结构特征的受感部参数化模型,并在Teamcenter中建立受感部参数化模型库。采用C#语言对NX进行二次开发,构建模型检索和重用、数值仿真、仿真报告生成等功能集成模块,最终建立了受感部参数化设计系统,提高了受感部的设计效率。     

桥式起重机参数化工程图模板制作方法研究

针对机械产品零部件参数化驱动后,工程图的自动生成方法及其生成工程图视图质量差等,研究了SolidWorks参数化工程图模板制作方法,该技术以模板最大化原则为依托建立参数化工程图模板,从而实现智能化快速出图,避免了重复性劳动,提高了效率。     

差动变压器式位移传感器参数化仿真技术研究

在建立合理的差动变压器式位移传感器(LVDT)电磁仿真模型的基础上,提出了一种基于脚本模板的电磁仿真参数化建模方法:首先将仿真建模过程录制成脚本,然后在脚本中添加标记形成脚本模板,最后将脚本模板中的标识动态修改为参数数值,实现了仿真模型的参数化建模;开发了LVDT参数化仿真系统并在工程中得到应用,显著提高了设计效率.     

复合材料热压罐模具温度场分析及二次开发

在复合材料热压罐成型工艺中,常用有限元分析技术对复合材料成型模具进行温度场分析.针对在仿真过程中存在的关键性问题,研究了参数化建模方法、网格生成方法、复合材料等效方法.并结合ANSYS Workbench软件平台,通过二次开发技术将温度场分析流程、参数化建模方法和网格生成方法开发成一套快速设计模板,以便提高仿真分析的效...     

基于梁单元的车身结构性能快速评估系统的开发

采用模板的方法构建了参数化的白车身概念设计线框模型,基于梁单元建立了柔性的车身结构有限元分析模型;建立了基于真实截面形状的参数化车身梁截面库,可直接计算截面的特性参数;实现了单元接头实现了对接头参数化精细模拟,提高了车身结构有限元模型的仿真分析精度;最后以实例的形式给出了该模型和详细车身结构模型的结构仿真分析的结果对比,结果表明采用梁单元模型构建车身结构符合车身设计初期的精度要求,并具有结构简单、计算速度快、易实现参数化等优点,适合在车身设计概念阶段快速评估车身的结构性能。     

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.