载荷对球轴承振动特性的影响

运用滚动轴承振动的数字化测量和分析系统，通过试验全面研究了轴向载荷、轴向和径向联合载荷对全钢球轴承、陶瓷球混合球轴承和全陶瓷球轴承的振动特性，验证了轴承振动的弹性接触模型，得出的结论对以减振降噪为目的的滚动轴承设计、安装和使用具有实际的指导意义。     

经典弹性点接触问题的数值求解与应用

线弹性点接触问题是弹性力学中的一个经典问题。本文采用数值手段对其进行了求解 ,给出了精度较高的详细图表 ,可用于指导相关点接触高副机构的设计分析。     

圆柱体接触问题中弹性趋近量的计算

运用接触分析中的柔度法,分析了两圆柱体接触时的弹性趋近量计算,在大量数值计算的基础上总结出了弹性趋近量的拟合公式.该公式除了包含以往经验公式中已考虑的影响因素以外,还考虑了接触体半径和沿轴向修缘凸度对弹性趋近量的影响,因而比常规的计算公式更为合理、精确.     

风电齿轮三维接触有限元分析

采用弹性接触有限元方法对1兆瓦风力发电机增速齿轮副进行了接触仿真分析,研究了齿轮啮合计算中的相关问题。利用三维建模软件Pro/E,建立了风电齿轮增速齿轮组传动系统的实体模型,利用有限元分析软件ANSYS,得到了增速齿轮组的应力和应变规律。根据计算结果,找出了风电齿轮增速齿轮组的最危险部位,对提高风力发电齿轮传动系统的承载能力和性能有一定的指导意义。     

微观随机粗糙表面接触有限元模型的构建与接触分析

基于相关文献提出粗糙表面模拟方法,通过软件工具在ANSYS中建立微观粗糙表面接触有限元模型,利用该模型分析载荷对弹塑性变形和接触面积的影响。结果表明:随着正压力的增大,粗糙表面上不断地有微凸峰与平面发生弹性接触变形,接触斑点(或接触斑点群)的数目逐渐增加,斑点中心区域的弹性变形很快达到最大,微凸峰负荷变形的同时也使斑点四周区域受到挤压;初始接触时,轮廓高度较大的微凸峰率先发生弹性变形,随着压力的增大,金属材料所受应力达到屈服极限同时粗糙表面的弹性变形和塑性变形的集中区域不断增加,真实接触面积不断增大;接触区数目的增多和接触区面积的增加都可以导致接触面上真实接触面积增加;随着压力的增大,真实接触面积的增大并不是由于接触区数目的增多,而是微观接触区面积的增大。     

循环对称钢片叠层接触问题的有限元分析

水力锚锚定过程中,涉及到膨胀的钢片相互呈循环对称接触、钢片齿牙井壁的锚定啮合.通过分析和简化,建立了相邻两渐开线钢片的有限元模型,并利用有限元分析软件ANSYS对相互接触的钢片进行了分析计算.绘制了钢片厚度等参数对接触应力影响的分布云图.在此基础上,对钢片的相关尺寸进行优化设计,主要是渐开线钢片厚度以及对应基圆半径大小进行了大量的计算机模拟,从而得出钢片的结构的优化结果.     

赫兹接触理论在采用边界元法分析轧机轴承载荷中的应用

在采用边界元法分析轧机轴承载荷的研究中,提出了一种修正算法,即首先假设一个接触宽度,利用赫兹接触理论进行修正,使用迭代算法进行计算,直到假设的接触宽度与修正后的接触宽度的差值满足给定的收敛条件,从而得到一个精确的结果。以某二辊轧机的四列圆锥轴承系统为例说明了方法的精确性。     

挠性气体动压径向轴承的理论分析

本文对挠性气体动压径向轴承提出了一种新的理论分析方法。用等参有限元法分析二维动压润滑，借助于约束矩阵和简化递推算法求解弹性体变形，得到了一定转速和偏心距下的气膜厚度和压力分布，计算了轴承的承载能力，刚度和起动力矩等性能参数。     

角接触球轴承沟道直径设计及相关分析

介绍了角接触球轴承沟道直径的计算计算方向，并给出了相关的计算式。分析了有关参数之间的相互关系，并得出了相应结论。     

滚动轴承弹性接触问题的数值计算

结合滚动轴承的弹性接触特点 ,重点论述了弹性接触理论的建模方法及理论数值解法 ,根据柔度法的理论思想编制了基于VC 的弹性接触应力数值计算软件并给出了计算实例 ,以此作为开展轴承CAE分析工作的基础和尝试。     

线接触问题的弹性趋近量与滚子轴承的载荷分布

在对迄今为止所出现的各种线接触问题弹性趋近量分析方法进行全面阐述的基础上，就一些主要的弹性趋近量算式及其在滚子轴承载荷分布计算中的应用进行了求解和对比分析，分析表明三体接触时采用H．Zantopulos公式的结果最差，而在滚子轴承载荷分布的理论分析体系中，G.Lundberg、A.Palmgren、Luc Houpert以及改进的切片法等理论的计算结果相差不大，可以根据需要选用。     

用规划法的齿轮有摩擦三维连续弹性接触分析

提出了柔度张量的概念,应用此概念和规划法来求解齿轮有摩擦三维连续弹性接触问题,相啮合齿的有限元网格可以独立划分,并只须一次有限元计算齿面网格结点柔度张量,齿面可能接触点在任意方向的柔度可以通过多元插值得到,然后建立有摩擦三维接触模型,采用逐步加载规划求解。在不同接触位置上,只需计算插值和规划,极大地减少了计算工作量,便于工程应用和推广。     

歪斜状况下滚子轴承的接触应力求解与分析

根据弹性接触理论,建立了滚子与滚道在歪斜工况下的接触模型,并结合影响系数法,编程求解了歪斜工况下滚子与滚道的接触问题。通过与赫兹理论解及有限元结果的对比,验证了程序结果的准确性。通过分析歪斜角、外载荷及滚道半径对滚子与滚道接触应力分布的影响,得到如下结论：歪斜工况下,滚子与滚道接触时会出现歪斜效应,即滚子与内圈接触时接触应力在接触副中部增大、两端减小,滚子与外圈接触时接触应力在接触副两端增大、中部减小;歪斜效应随着歪斜角的增大、外载荷的减小及滚道半径的减小而逐渐明显。     

Note on the complete contact between a flat rigid punch and an elastic layer attached to a dissimilar substrate

The contact pressure distribution is found for a square ended rigid punch, pressing normally onto an elastic layer, itself attached to an elastically dissimilar half-plane, under plane deformation. Each interface may be either frictionless or adhesive, and it is shown that the shear traction assumption has only a very small influence on the contact pressure, which is found as a perturbation on the classical Flamant half-plane solution. For thin layers the contact pressure distribution is only weakly dependent on the pad aspect ratio.     

Flat and rounded fretting contact problems incorporating elastic layers

The problem of plane elastic contact between a thin strip and symmetric flat and rounded punches is studied. This geometry has recently been used by a number of researchers to assess life of various mechanical couplings undergoing fretting fatigue. Most of the experimental fixtures used do not allow the problem to be treated using the conventional half-plane approximation. Here we propose a numerical approach, which enables the solution of configurations characterised by finite strip thickness, avoiding the use of finite element analyses. Various loading regimes and contact configurations are treated in detail and both surface tractions and internal stresses are derived.     

弹性压杆稳定计算的方块脉冲函数法

弹性压杆特别是变截面压杆，要推导出其稳定方程和计算临界载荷是十分繁琐甚至是不可能的。这里利用方块脉冲函数(BPF)的良好运算性质直接求解弹性压杆稳定的能量泛函极值，将计算临界载荷转化为求矩阵的特征值问题，从而得到了计算弹性压杆失稳临界载荷的一种新的数值方法。该方法对于等截面压杆和变截面压杆均适用，具有计算简洁、便于计算机处理等优点，有很好的工程应用价值。     

Validation of a simplified numerical contact model

Surface roughness tends to have a significant effect on how loads are transmitted at the contact interface between solid bodies. Most numerical contact models for analyzing rough surface contacts are computational demanding and more computationally efficient contact models are required. Depending on the purpose of the simulation, simplified and less accurate models can be preferable to more accurate, but also more complex, models. This paper discusses a simplified contact model called the elastic foundation model and its applicability to rough surfaces. The advantage of the model is that it is fast to evaluate, but its disadvantage is that it only gives an approximate solution to the contact problem. It is studied how surface roughness influences the errors in the elastic foundation solution in terms of predicted pressure distribution, real contact area, and normal and tangential contact stiffness. The results can be used to estimate the extent of error in the elastic foundation model, depending on the degree of surface roughness. The conclusion is that the elastic foundation model is not accurate enough to give a correct prediction of the actual contact stresses and contact areas, but it might be good enough for simulations where contact stiffness are of interest.     

Elastic and elastic-perfectly plastic analysis of an axisymmetric sinusoidal surface asperity contact

ABSTRACT

Closed-form finite-element empirical models are available for elastic and elastic–plastic spherical and sinusoidal contact. However, some of these models do not consider the effect of interaction with adjacent asperities or require extensive numerical resources because they employ a full 3-D model. Therefore this work has analysed and quantified the behaviour of an elastic and elastic- perfectly plastic axisymmetric sinusoidal surface in contact with a rigid flat for a wide range of material properties and different values of the amplitude to wavelength ratio from initial to complete contact (high load). The numerical results agreed well with the Hertz model and the Jackson–Green elastic–plastic spherical contact model at low loads. Empirical equations for elastic and also elastic-perfectly plastic cases are formulated for the contact pressure, contact area and surface separation. From the current analysis, it is found that it is not any single parameter, but different combinations of material properties and surface roughness that govern the whole contact behaviour. The critical value of the amplitude of the sinusoidal asperity below which it will deform completely elastically from initial to complete contact is established. At low values of amplitude normalized by the critical amplitude, it was found that the contact behaved similar to a spherical contact, with the average pressure (hardness) always remaining lower than three times the yield strength. However, at higher values the average pressure increased toward a value as high as six times the yield strength at complete contact. All of these equations should be useful in rough surface contact modelling, lubrication analysis, electrical contact modelling and in many other applications.     

接触变形与点啮合共轭齿廓传动性能预控

本文采用ＢＡＸＴＥＲ方法首次根据空间啮合原理和弹性力学理论考虑齿廓点接触区变形,它着重说明收缩齿制螺旋齿轮副弹性失配点啮合的性能和齿接触迹的予控。     

On the elastic contact of rough surfaces: Numerical experiments and comparisons with recent theories

Some numerical experiments are conducted for studying the decrease of the elastic contact area in the elastic contact of fractal random surfaces when adding components of roughness of progressively smaller wavelengths. In particular, Fourier and Weierstrass random series are used, and a recent accurate and efficient method developed by the authors is used, involving superpositions of overlapping triangles. Some comparisons are made using two recent theories, that of Ciavarella et al. published in 2000 on the deterministic Weierstrass fractal profile, and that of Persson published in 2001 on random generic contact. We show that both theories tend to underpredict the contact area by a significant (and similar) factor in these representative cases in the region of light loads (partial contact), where the non-linearities of the contact mechanics are not included in neither of the formulations. In Persson's theory case, the discrepancy is particularly large at high fractal dimensions of the profile, where in theory the numerical experiments should be more closely reproducing a true Gaussian process. The Ciavarella et al. “Archard-like” theory, is only accurate when the parameter γ (the ratio of successive wavelengths) is unrealistically large. However, we only tested the Ciavarella et al. theory in the simplified “Hertzian approximation” form assuming partial contact at the peaks of contact, although we don’t expect the full version to improve dramatically the results.