基于蒙特卡罗法的行星齿轮机构稳健性分析

以行星齿轮机构体积最小为优化目标,以太阳轮齿数、齿宽、模数、行星齿轮个数为设计变量,以齿轮轮齿接触强度、齿轮轮齿弯曲强度、相邻条件等为约束条件,建立了某行星齿轮机构数学模型,并应用遗传算法求解了优化结果.将设计变量考虑为具有正态分布特征的随机变量,应用蒙特卡罗方法对行星齿轮机构进行稳健性分析,包括随机变量影响下的目标函数、约束条件的概率分布.分析表明,设计变量存在微小变化时,行星齿轮机构稳健性差.重新设定精度后,行星齿轮机构稳健性得到提高,满足了设计要求.     

基于KISSsoft的采煤机齿轮箱参数优化设计

以某采煤机齿轮箱第四级行星齿轮传动系统为研究对象,通过KISSsoft软件建立齿轮组参数化模型,分析了在传动过程中主要参数对齿轮系统的影响。以最小齿根弯曲疲劳强度安全系数和最小齿面接触疲劳强度安全系数为目标函数,以螺旋角、模数、传动比、齿数、齿宽比和内孔径及轮缘厚度为约束条件,构建数学模型对齿轮设计参数进行优化,改善了采煤机齿轮箱传动中存在的问题。通过对比分析优化前后的齿轮传动性能,优化后的传动模型表现出了更高的可靠性和使用寿命。研究了优化后的齿轮箱传动模型各参数指标,确保最佳优化方案。所进行的研究工作对其他齿轮传动装备的优化与设计具有重要的参考价值。     

机床零件的袖诊计算机计算程序(五)

机床标准直齿、斜齿圆柱齿轮的强度设计及校核计算(一) 1.概述 机床齿轮计算一般分为二种情况,一种按接触疲劳强度设计模数、齿数,再按弯曲疲劳强度校校。另一种是在初步设计齿轮的基础上进行接触疲劳强度及弯曲疲劳强度的校校。其公式为。(外啮合) (1)直齿轮传动接触疲劳强度计算(根据《机床设计手册》2册上266页)。 a.设计公式:(3)直齿轮传动弯曲疲劳强度计算。a.设计公式:b.校核公式:(4)斜齿轮传动弯曲疲劳强度计算a.设计公式:b .校核公式 m、mn──模数及法面模数(cm)。 [σ]──齿轮材料的许用接触应力(kgf/cm2)。 [σw]──齿轮材料的…     

纯滚动单圆弧齿轮多目标模糊优化设计

文章综合利用模糊评判方法和多目标优化设计方法,以相对主曲率半径最大、重合度最大和齿轮传动总体积最小为优化目标,建立了纯滚动单圆弧齿轮传动机构的多目标模糊优化模型,并对其进行单目标分析和多目标优化设计。设计分析得出：法向模数对纯滚动单圆弧齿轮的相对主曲率半径影响权重最大,其次是齿数、齿廓系数、螺旋角、齿宽系数。其中齿数、齿宽系数、螺旋角对纵向重合度影响大,并且随之增加而减小;法向模数、齿数、齿宽系数则对齿轮体积和影响大,并且随之增加而增加。影响程度从高到低的排序为：法向模数、齿数、齿宽系数、螺旋角、齿廓系数。所得结论为纯滚动单圆弧齿轮的受力改善和轻量化设计提供了理论参考和依据。     

采煤机摇臂齿轮传动系统的可靠性优化设计

针对采煤机摇臂齿轮传动系统的设计,以可靠性设计理论为基础,推导出在齿轮强度、应力都服从正态分布时的齿面接触疲劳强度和齿根弯曲疲劳强度为约束条件,齿轮系体积最小为目标函数的优化数学模型,通过Matlab的遗传算法优化工具箱对其进行优化求解。实例结果表明,方法得到的设计参数能有效地提高摇臂齿轮传动系统的可靠度,减小齿轮传动系统的体积、重量,有利于实现产品轻量化,节约成本。     

大型行星齿轮系统可靠性设计的多目标优化

大型行星齿轮传动系统工况复杂,安全性能要求高,常规的设计方法因过于注重安全性,设计的结果偏于保守,技术经济指标不佳.以行星齿轮传动系统为对象,提出了大型机构可靠性设计的多目标优化模型,即以齿轮的关键参数——齿数、齿宽、模数为设计变量,充分考虑工程设计的约束性、多解性等特征,建立数学模型,进行可靠性分析计算,并在MATLAB优化工具箱里采用积极集策略进行多目标优化.将得到的结果与传统设计方案结果相比较,为大型行星齿轮系统的优化设计提供新思路.     

基于遗传算法的圆柱齿轮变位系数的优化选择方法

合理地选择和分配齿轮传动机构中两齿轮的变位系数 ,能较大幅度地提高其齿面接触疲劳强度与齿根弯曲疲劳强度 ,减轻齿面磨损及防止胶合 ,从而设计出承载能力大、效率高、体积小、重量轻的齿轮机构。鉴于遗传算法的特点 ,提出了基于 GA的圆柱齿轮变位系数的优化方法 ,优化计算实例说明了该方法的可行性     

基于MATLAB的齿轮减速器优化设计

以减速器中齿轮的齿数、模数、齿宽及轴的直径等作为设计变量，以减速器的体积为目标函数，利用MATLAB的优化工具箱，对减速器进行优化设计，简化了复杂的编程，提高了设计效率和质量。     

智能排爆机器人机械手部设计及其优化

利用排爆机器人技术结合现代设计方法,并根据结构特点,以质量最轻最优为目标,以几何尺寸、蜗轮齿面疲劳强度、蜗杆特性系数、模数、齿数、等为约束条件,对排爆机器人的机械手部进行了结构优化,使得机械手部结构好、质量轻、运动灵活.     

基于行星减速器的多目标可靠性优化设计方法研究

将优化技术与可靠性设计理论相结合,以齿轮疲劳强度可靠度和行星轮系配齿条件等为约束,以行星齿轮减速器传动效率高、重量轻、体积小为优化目标,根据工程实践和统一目标函数法建立其优化数学模型,应用混合惩罚函数法、Powell法等多种优化算法对其进行优化设计[1].通过实例说明,应用这种理论方法可在保证减速器使用寿命的前提下,得到满意的优化结果.     

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.