基于MSC有限元分析的五缸往复泵曲轴疲劳强度校核

针对五缸往复泵曲轴结构形状和受力情况都比较复杂的状况,通过对五拐三支承曲轴建立整体三维模型,在MSC.Patran/MSC.Nastran软件环境下对其进行有限元模态分析,并联合动力学仿真软件MSC.Adams对该曲轴进行瞬态动力学有限元分析,得到曲轴在工作循环中的最大危险点及其应力值,并利用这些数据进行疲劳强度校核.提出了一种基于模态法瞬态有限元分析的曲轴疲劳强度校核的方法,为往复泵曲轴设计和疲劳强度校核计算提供了有价值的指导参考.     

M型高压水泵曲轴断裂机理分析及改进设计

为了解决M型高压水泵曲轴断裂的问题,在对M泵曲轴断裂情况进行充分分析的基础上,应用Ansys有限元对曲轴进行了受力分析,通过仿真分析发现其应力集中严重的部位与断裂部位重合,同时根据实际的断裂情况对曲轴倒角的设计进行了仿真计算,重新确定了倒角的大小。为了进一步验证断裂的情况,应用解析法对其断裂截面的疲劳强度进行了校核计算,计算结果表明,原4 mm倒角情况下曲轴的疲劳强度安全系数低于许用安全系数,改进为8 mm倒角后疲劳强度安全系数满足设计要求。在此基础上对M泵的曲轴进行了改进设计,改进后的应用效果显著,解决了困扰企业的曲轴断裂问题。     

高强度曲轴静态特性仿真与试验研究

采用ANSYS有限元软件,建立了480柴油机整体和单拐曲轴的静态特性分析模型,针对不同的约束条件,对两种模型的弯曲疲劳强度进行计算,指出了两种模型下的应力集中区域以及应力分布和变形情况;两种模型应力值均未超出曲轴的许用应力。通过曲轴弯曲疲劳强度试验,对480柴油机单拐曲轴进行了弯曲疲劳试验,测量了弯矩随循环基数的变化情况。结果表明,采用整体和单拐曲轴的静态特性分析模型,应力集中比较危险的区域出现在主轴颈、连杆轴颈与曲柄臂的过渡圆角区域;整体较于单拐模型可以更全面、真实反映曲轴各拐的静态特性。     

基于多体动力学的曲轴疲劳强度分析

以某六缸柴油机曲轴为研究对象,运用多体动力学和有限元相结合的方法对其进行疲劳强度计算。首先建立曲柄连杆机构多刚体动力学模型,进行动态仿真分析,获得曲轴有限元分析的载荷边界条件,然后建立能模拟曲轴与轴承间接触状态的有限元模型,对曲轴危险工况进行接触有限元分析,最后校核了曲轴的疲劳强度。计算结果表明,分析方法合理,所研究曲轴的疲劳强度满足设计和运行工况要求,同时,该计算方法能够较真实地模拟曲轴的实际工作状况,可为曲轴的强度计算提供一定的参考依据。     

基于有限元法的柱塞泵曲轴疲劳强度分析

该文基于有限元分析方法,将曲轴划分为89个形状规则的组成部分,创建了72个用于施加连杆力载荷的工作坐标。在设计工况(柱塞推力6500kg)下,对曲轴按照每隔15°一个角度工况,共24个不同角度上的工作载荷情况进行静力有限元分析,共得到24种工况的应力场及应力强度。对曲柄销与曲柄过渡的圆角面进行了详细的疲劳强度分析,并对安全系数最小节点的应力值变化规律进行了描述。     

6108柴油机曲轴有限元分析

应用有限元分析软件ANSYS,建立了6108柴油机曲轴的三维有限元模型,按标准工况求出曲轴各连杆轴颈载荷,模拟曲轴的力边界条件和位移边界条件进行了曲轴静力学分析;并校核了在危险载荷作用下曲轴的疲劳强度;同时对曲轴进行了自由模态分析,得出各阶振型和频率,计算结果较真实地反映了曲轴固有频率特性,为柴油机曲轴的改型设计提供了一些参考。     

基于虚拟样机的汽车空调压缩机曲轴力学分析

按虚拟样机思想,利用动力学分析技术和有限元分析技术相结合的方法,快速精确地对汽车空调压缩机在三种不同转速下,曲轴曲柄销受力、应力分布情况和疲劳强度进行分析比较。为改进压缩机的曲轴设计提供了参考依据。     

连杆动应力及疲劳寿命分析

连杆在发动机中直接与活塞销、曲轴连杆轴颈相连接,它们之间通过弹性接触传递力。所以,活塞销、曲轴连杆轴颈决定了连杆的受力分布情况。采用有限元分析中的接触法对某型号发动机的连杆进行有限元分析,得出接触面之间的压力分布情况、连杆的应力分布情况及连杆变形情况,并对连杆的疲劳强度进行校核。     

柴油机曲轴三维有限元可靠性分析

运用有限元软件分析了柴油机曲轴在交变弯曲载荷下的应力分布和疲劳强度。以最大爆发压力工况和最大拉力工况作为计算工况,计算了曲轴的应力分布;对最大爆发压力工况和最大拉力工况下的应力进行等效转化疲劳应力计算;最后采用安全系数判断了曲轴的疲劳强度。     

基于UG环境下的压缩机曲轴强度计算与分析

利用有限元分析的方法和UG软件的功能,对活塞压缩机的曲轴创建三维力的分析模型,探讨进行曲轴的静强度和疲劳强度的校核方法,并结合曲轴实例建模、解算.     

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.     

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....     

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.     

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.