某型飞机前起落架焊接部位应力应变分析

起落架是飞机起飞和着陆的关键部位。某型飞机前起落架的缓冲支柱与横梁通过焊接连结,而焊接部位的性能受焊接质量影响很大,准确分析不同焊接部位的焊接质量及在各种情况下的应力应变,对于该飞机前起落架的使用和维修具有深远的意义。本文利用有限元软件,建立焊接部位实体模型,通过模拟加载,对起落架的焊接部位进行应力应变分析,找到应力最大的危险点。     

基于子模型算法的某螺旋桨遥测盘局部强度计算与分析

针对传统有限元对大型旋转件进行数值模拟时网格数量多、计算精度低、应力集中难以表征等缺点,应用有限元子模型算法,对某旋转遥测盘的局部旋转强度进行了详细计算分析。在ANSYS软件中建立了基于循环对称的全局有限元模型,计算最大工作转速的应力分布情况,确定高应力区。根据全局模型结果建立高精度的子模型,进一步模拟子模型的应力分布情况,得到危险点应力,进行了强度校核,结果表明考核部位的局部强度满足设计要求。     

SGA3723 45t矿用自卸车驱动桥的强度分析

建立了SGA3723型矿用汽车驱动桥壳及A形架的有限元模型,对极限工况利用ANSYS软件进行了结构强度分析,计算出危险点的最大应力值。结果表明,该驱动桥壳和A型架的应力符合强度要求。     

36t集装箱门式起重机吊具上架疲劳寿命估算

用有限元分析软件ANSYS对吊具上架结构进行静态应力分析,获得结构的危险点位置,通过利用起重机动力学求出载荷时间历程,结合由Matlab软件产生的随机起重量获得典型载荷循环块。之后,基于载荷时间历程,危险应力分布和Miner损伤理论,利用FE-FATIGUE软件计算出吊具上架的疲劳损伤。     

液压镦锻机下横梁结构的静态有限元分析

在对某液压机下横梁结构特点研究的基础上,以有限元软件ANSYS为工具,选用实体单元建立下横梁结构的有限元模型,并对模型进行了整体静态有限元分析,揭示下横梁结构的应力和应变的分布规律,获得了受力及变形危险点的位置,为其进行结构改进提供了重要的依据。     

5kW离网小型风力发电机主轴的疲劳分析

以处于试制阶段的新型5 kW离网小型风力发电机主轴为研究对象,对该主轴进行了两种工作位置下的极限载荷分析.在确认分析结果正确后找出了该主轴上可能发生疲劳破坏的两个危险点,并得出这两个点的应力变化规律,通过有限元软件ANSYS求出这两个危险点在发生疲劳破坏前应力循环的次数,验证了该主轴能满足设计疲劳寿命.     

汽车车轮弯曲疲劳试验分析研究

针对车轮动态弯曲疲劳试验, 对车轮结构在三种作用力( 螺栓预紧力、离心力和试验弯矩)下的应力分布情况,分别进行有限元分析,可以有效反映离心力对车轮结构应力分布的影响,以及动态弯矩作用下车轮结构的危险点和应力分布的变化情况.结构危险点的计算应力反映该处的应力集中程度.进行螺栓孔变形试验,验证螺栓预紧力作用下螺栓孔变形量的有限元计算结果.对车轮结构危险点进行静态和旋转一周的实验应力分析,验证动态弯矩有限元分析结果.分析表明,采用材料线性有限元分析并不能有效模拟螺栓孔变形量,离心力对车轮结构应力分布影响不大,可以忽略,动态弯曲疲劳试验中,车轮结构各点承受的是非对称应力循环,弯曲试验的动态弯矩有限元分析能较好地模拟出车轮结构的应力水平,给后续的疲劳寿命分析提供更可靠的依据.     

汽车车轮结构强度分析

针对车轮动态弯曲疲劳试验建立了两种轿车车轮的静态线性有限元模型，它们可以有效地用来确定车轮结构的危险点，即结构中计算应力（von Mises应力）比较大的点。结构危险点的计算应力反映该处的应力集中程度。对车轮结构上计算应力较大的测点进行实验应力分析，验证有限元分析结果。对结构危险点的应力状态进行分析，有助于预测车轮疲劳裂纹的发生方向和引起疲劳损伤的主要应力循环，在所研究的车轮结构中也就是沿着车轮径向的正应力变程。分析还表明，在动态弯曲疲劳试验中，车轮结构各点所承受的可能是非对称应力循环。     

石油钻头的实体建模及有限元分析

石油钻头是一种形状较复杂的孔加工工具,其参数不易获取,通过光学测量技术对钻头扫描,逆向工程软件对钻头的点云数据进行处理,再利用三维软件实现三维建模;应用有限元分析软件对钻头进行有限元的数值模拟分析,可较精确地掌握钻头在工作过程中各点的受力情况,了解钻头内部应力应变的分布规律,获得应力分布图并方便地找出钻头上的危险点,为今后改进钻头的受力情况、合理设计钻头结构以及对钻头进行失效分析提供理论依据。     

基于ANSYS的驱动桥壳瞬态动力学和疲劳寿命分析

以有限元法为基础,在建立驱动桥桥壳的有限元力学模型的基础上,先借助有限元软件ANSYS的瞬态动力学分析找出桥壳上的危险点,再通过ANSYS-Fatigue疲劳分析模块对桥壳进行疲劳寿命分析,得到桥壳整体的疲劳寿命分布。桥壳的危险部位主要分布于圆弧过渡区域,与台架实验结果基本一致。从而验证了有限元软件对驱动桥壳理论分析的正确性,为驱动桥壳的设计和相关性能的分析提供了一种方法。     

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.     

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....     

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.     

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.