商用车驱动桥壳CAE分析

文中主要针对某商用车驱动桥壳半轴套管出现大量断裂问题,采用UG软件进行了三维实体建模,通过导入Hypermesh进行划分网格等前处理,利用MSC.Nastran对其进行有限元分析.并按照驱动桥壳静强度分析理论对车桥壳体进行了分析计算.结果表明:该驱动桥壳半轴套管的静强度安全系数和疲劳安全系数均小于许用极限值,从理论上验证了半轴套管会发生疲劳断裂;并提出了改进材料重新选用40钢的新方案,使其静强度和疲劳强度在理论和试验中均能满足桥壳的设计和运行工况的要求.     

汽车离合器传动片可靠性分析

文中针对应用离合器中的传动片进行静强度和疲劳强度分析。首先建立了离合器传动片的力学模型,通过有限元分析得到了传动片的应力分布和疲劳寿命,最后通过试验验证传动片分析的正确性。在对传动片有限元分析中,首先采用Hypermesh软件针对三维模型进行网格划分,把划分好网格后把网格导入到abaqus软件中,根据建立好的力学模型,对模型施加边界条件,并求解得到传动片应力分布云图。然后根据线性疲劳累积损伤理论,采用应变-寿命法对模型进行疲劳分析,得到传动片的疲劳寿命。     

基于ANSYS Workbench的热压机框架疲劳强度分析及优化

以某型号人造板热压机为分析对象,基于材料力学、断裂力学和局部应力应变法,给出了热压机框架的疲劳寿命计算方法.通过CATIA建立其三维实体模型,在ANSYS Workbench中进行有限元网格划分,并进行了静力学分析,再通过ANSYS Workbench中的Fatigue Tool模块进行了基于静力学分析的疲劳强度分析.结果表明:构件的疲劳寿命主要受薄弱环节的疲劳状况影响,应力集中部位的疲劳寿命最低.根据有限元仿真分析,对框架结构进行了优化设计,使得应力集中有了一定的减小,疲劳寿命有了明显提高.     

新型反应釜釜内螺旋叶片强度分析与疲劳寿命预测

使用大型有限元分析软件ANSYS对新型反应釜釜内螺旋叶片进行三维有限元建模,并建立相应的力学模型.通过有限元分析对螺旋叶片进行静强度校核,同时利用相关标准中的数据预测了螺旋叶片的疲劳寿命,为螺旋叶片的设计选择提供可靠的理论依据.     

微车半轴轴承的计算校核探讨

主要针对半轴轴承的计算校核进行探讨分析,完善轴承的计算校核,确保轴承的强度、寿命以及保证轴承在许用轴向力和偏摆角内工作。同时解决以往校核不完善而导致半轴轴承异常磨损及异响问题,为后续车型开发提供参考。     

基于接触分析的高强度螺栓疲劳寿命分析

针对结构复杂的螺栓连接及螺栓受力的复杂性,提出一种新的计算螺栓疲劳寿命的方法.本文通过有限元建模对某MW级风力发电机组塔筒法兰螺栓进行强度分析,并对应力最大螺栓进行分布加载计算;在MATLAB/simulink中对计算结果进行编程运算,拟合出螺栓载荷应力曲线;采用雨流计数法对载荷谱进行处理,结合材料的S-N曲线在Palmgrem-Miner理论准则下,并借助于MSC.Fatigue软件计算得到螺栓的疲劳寿命.同时应用Schmidt-Neuper理论及VD12230对螺栓疲劳寿命进行校核验证,得出这种新的螺栓疲劳方法的合理性.     

基于nCode的新型汽车半轴的疲劳分析

根据汽车半轴实际受力状况和摆线型面联接的特点提出一种新型半轴,并且运用有限元理论和疲劳分析理论对其进行有限元分析和疲劳可靠性分析。首先对新型半轴的简化结构进行了建模和有限元静态特性分析,然后定义了载荷谱和材料参数,选用S-N疲劳设计,利用疲劳分析软件n Code Design-Life对该结构进行了疲劳可靠性分析,得出模型的疲劳损伤云图和各节点的疲劳寿命,确定了容易发生疲劳破坏的位置和各节点的疲劳寿命,为半轴结构的进一步优化设计提供了理论依据。     

汽车后桥半轴的疲劳寿命预测分析

为了提高汽车后桥半轴疲劳寿命检验的效率以及检测的安全性,基于虚拟现实技术提出了一种台架试验与仿真相结合的复合分析检验方法.在一定量台架试验基础上,利用Pro/E参数化设计方法,对汽车后桥半轴进行三维实体建模,ANSYS WorKbench有限元疲劳分析模块对后桥半轴进行疲劳寿命预测分析,获得的结果与一定量台架检验的结果对比分析,得出预测结果与试验结果一致,验证了方法的正确性.这种复合的检验方法相对于单-的台架检验方法,减少了产品的试验样品数量,缩短了开发周期,提高了安全性,降低了开发成本,同时也为农用、工程车辆传动系冲击性能的研究提供了参考.     

某型主战坦克扭力轴的疲劳断裂分析与寿命计算

应用断裂力学理论和有限元分析方法对某型主战坦克扭力轴进行疲劳断裂计算和分析，论述裂纹尖端的奇异三角形单元划分技术，在有限元法计算的基础上求解裂纹尖端应力强度因子和裂纹形状系数，并结合Paris公式对某坦克扭力轴的疲劳寿命进行计算。     

单元大小对货车车体强度及疲劳有限元分析结果影响研究

对C70敞车车体进行三维几何建模,然后分别使用边长为20 mm和30 mm的壳单元对其进行有限元划分,最后基于铁路相关规范分析计算不同单元大小的敞车车体强度,根据IIW标准对敞车车体进行疲劳寿命评估。计算结果显示,在同种工况下,单元大小的改变对车体强度的计算结果影响较小,对疲劳寿命的计算结果影响较大,即车体强度的计算结果对单元大小不敏感,疲劳寿命的计算结果对单元大小敏感。在使用IIW标准计算疲劳寿命时,为了避免单元大小敏感特性,需要在焊缝处进行单元节点细化,保证疲劳寿命计算结果的稳定性。     

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...     

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。     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.