20CrMnMo齿轮弯曲疲劳性能试验研究

将同一批次加工的20CrMnMo齿轮分为两组,其中一组经过齿根喷丸强化后,分别对两组齿轮进行弯曲疲劳强度试验,通过对试验数据的处理,获得两组齿轮的R-S-N曲线和不同可靠度的极限应力,为后续齿轮设计制造提供了必要的试验数据。     

25Cr2Ni4WA合金钢渗碳淬火齿轮的弯曲疲劳试验分析

采用双齿弯曲脉动加载试验法,进行了25Cr2Ni4WA齿轮弯曲疲劳强度试验.根据试验所得数据,按统计学原理,拟合出S-N曲线,并获得不同置信度、可靠度下的弯曲疲劳极限应力值;能为该材料齿轮的弯曲疲劳可靠性设计提供了实践基础数据.     

42CrMo钢渗碳淬火齿轮弯曲疲劳极限快速测定

针对42CrMo钢生产新齿轮的需要,进行了齿轮弯曲疲劳强度试验。在对该材料进行化学成分分析和硬度检测后,提出基于LOCATI方法进行双齿脉动加载试验。根据试验所得数据,按统计学原理,拟合出S-N曲线,并获得置信度为95%、可靠度为95%的弯曲疲劳极限应力值。为该材料齿轮的弯曲疲劳可靠性设计、有限寿命设计提供了真实的试验依据。     

37SiMn2MoV调质齿轮弯曲疲劳强度的试验研究

论述37SiMn2MoV调质齿轮弯曲疲劳强度的试验研究.在试验数据的基础上,根据统计学原理,拟合出完整的C-R-S-N曲线,并获得指定置信度下,各种可靠度时的弯曲疲劳曲线,从而为国产材料齿轮设计提供了必要的基础数据.     

齿轮强化喷丸在岸边集装箱起重机齿轮箱中的应用

以岸桥集装箱起重机齿轮箱中各级齿轮为研究对象,介绍了一种利用高频疲劳试验机,对喷丸和未喷丸渗碳淬火齿轮做脉动试验的方法,得出各试验齿轮的弯曲疲劳强度及存活率、应力、寿命曲线,通过弯曲疲劳强度试验对比,以验证实施强化喷丸处理。     

服从正态分布随机载荷作用下齿轮弯曲疲劳试验研究

根据齿轮传动过程中普遍承受的高斯分布载荷谱,编制了试验用随机变幅疲劳载荷谱,在MTS电液伺服疲劳试验机上利用成组试验方法完成了该随机载荷作用下全寿命齿轮弯曲疲劳试验,得到了特定变差系数高斯分布载荷谱下齿轮弯曲强度的R-S-N曲线。试验结果证明,随机变幅疲劳试验得出的轮齿疲劳寿命低于由疲劳载荷上限值取为载荷谱均值的恒载荷疲劳试验得出的疲劳寿命,因此,如果采用后者的试验结果去估算实际服役中的齿轮的弯曲疲劳寿命是非常危险的。对随机载荷下的齿轮设计的疲劳极限的理论值进行了预测,并与试验结果进行了比较。结果表明,理论分析结果与试验结果基本相符。     

齿轮疲劳极限应力快速测定法

本文提出了一种新的快速齿轮疲劳试验方法。即基于Miner理论的Locati方法应用于齿轮的疲劳试验。这种方法仅用一对齿轮,采用台阶增载的加载方法,一次试验即可测出齿轮的疲劳强度极限值(齿面接触疲劳强度极限值或齿根弯曲疲劳强度极限值)。文中叙述了用这种方法所做的六对齿轮试验情况,其中两对齿轮做齿根弯曲疲劳试验;四对(两种不同材质的)齿轮作齿面接触疲劳试验。试验结果表明:测定出的疲劳强度极限值相当接近于用常规试验所测定的值。本文还对快速试验方法进行了分析讨论。     

35CrNiMo感应淬火齿轮接触疲劳强度试验

限于大模数齿条新材料35Cr Ni Mo弯曲接触疲劳基础数据的空白,采用成组与爬山试验方法,获得了三峡升船机大模数齿条新材料35Cr Ni Mo感应淬火齿轮接触疲劳极限,基于labview软件的数据处理方法,得到了齿轮的疲劳极限应力、接触疲劳寿命分布和不同可靠度下的R-S-N曲线族,为该材料齿轮齿条可靠性设计提供了基础数据。     

升降法测定齿轮的弯曲疲劳极限

齿轮弯曲疲劳强度是衡量齿轮性能的重要指标,开展齿轮试验是获得齿轮弯曲强度的有效方法。针对20Cr Mo H渗碳齿轮,采用升降法开展单齿弯曲疲劳强度试验研究,基于脉动加载法和成组试验方案,在电磁谐振疲劳试验机上对齿轮轮齿进行了5个应力级的疲劳强度试验;依据平截面和折截面两种方法计算轮齿齿根应力,分析得到了该齿轮的弯曲疲劳极限;结合轮齿裂纹位置和断口形貌,分析了形成原因,结果表明,折截面法确定的危险截面位置更加符合实际,为进一步研究齿轮的弯曲疲劳强度提供了基本思路。     

齿轮弯曲概率强度研究

本文在讨论齿轮弯曲载荷谱的基础上,借助疲劳寿命和疲劳强度之间的破坏率等同性原理,根据齿轮弯曲疲劳寿命分布求出其疲劳强度概率分布.应用实例显示了该模型能反映出齿轮弯曲疲劳强度随时间延续而变化的动态关系.     

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.