共查询到19条相似文献,搜索用时 125 毫秒
1.
对两个有限长,外载荷又集中作用的圆拄体,在接触面上的应力分布是不均匀的.为了获得接触应力,本文应用弹性力学的理论、光弹性应力分析方法和有限元计算概念,提出了一种混合计算法.最后给出一个应用实例,讨论了某轧机轧辊的接触问题. 相似文献
2.
本文研究覆盖在一个钢辊上薄弹性层的厚度、材料性质对辊柱间接触面的应力分布和微小滑移的影响。基于弹性理论,以试凑法求解一组接触面间位移的协调方程。并用FORTRAN语言编写了计算程序,计算表明在无滑移的自由辊压条件下,法向应力沿接触长度与中心对称,而切应力呈反对称。随着厚度和弹性性质的变化,切应力不仅大小而且方向也发生变化。在有微小滑移的自由辊压和受拖动辊压时,沿接触长度存在三个滑移区,并随拖动力的增加而变化。 相似文献
3.
叶片榫头接触应力的求解研究 总被引:2,自引:0,他引:2
接触应力分析是不易检测、难于计算,但对于设计又是非常重要的一个难题。文中将实验检测技术与数值计算方法相结合,求解飞机发动机叶片榫头上的接触应力分布。基本思路是:1)用实验检测技术求出叶片榫头接触面上若干点的应力或应变值;2)通过给叶片根部接触面施加一定的约束条件,用数值计算法计算发动机叶片在离心力载荷作用下的全场应力分布,并进一步求出接触面上的接触应力分布;3)解除接触面上的约束条件,代之以计算获得的接触载荷,计算叶片在离心力载荷以及接触载荷共同作用下的全场应力或应变分布,并比较计算结果与实验结果;4)修改约束条件或计算模型,重复上述操作,直至计算结果与实验结果比较一致。研究表明,本文提出的方法能够较准确地给出接触面的载荷分布,判断约束条件的合理性具有简单、易行的特点。由于接触应力的复杂性,本问题还有深入研究的必要。 相似文献
4.
轧机油膜轴承频繁出现巴氏合金剥落、龟裂等现象,直接影响到油膜轴承的使用寿命和轧制生产的正常进行,应用三维弹性接触问题的边界元法对宝钢2050支承辊油膜轴承载荷分布进行分析研究,建立了油膜轴承的接触模型,模拟真实的约束与受力,结果轴承出现严重偏载现象,通过改善约束条件,在自位情况下轴承偏载现象大幅度降低,同时接触应力也在一定程度上减小,从而使得轴承的承载能力得到提高,由于考虑了弹性变形的影响,该方法具有计算精度高,收敛速度快等优点。 相似文献
5.
采用边界元法对高度非线性的滚动轴承接触问题进行了研究。利用轴承边界单元模拟轴承接触单元,采用赫兹接触理论对滚动体与轴承内外圈的接触宽度进行修正;根据轧机圆锥滚子轴承安装配合时轴承内圈与轧辊、轴承外圈与轴承座均采用松配合的特点,在多物体有摩擦弹性接触的边界元法基础上,编制了四物体有摩擦弹性接触的专用轴承边界元法计算程序;并对轧机四列圆锥滚子轴承进行了数值分析,验证了算法的可行性和有效性。结果表明:四列滚动体上圆锥滚子小端受较大的压力,且滚动体端部压力远大于中部压力;滚动体承受的轴向压力与四列圆锥轴承的锥度分布一致,最大应力出现在第一列滚动体靠近辊身侧的位置;各个滚动体的接触宽度与滚动体上承受的径向载荷分布规律一致,非轴承接触面所受载荷的分布与承受载荷的滚动体的位置相对应。 相似文献
6.
7.
考虑接触应力非线性分布的接触力元模式及其验证分析 总被引:1,自引:0,他引:1
在作者提出的非连续变形计算力学模型中,采用接触力元模型描述多体接触界面上的接触特性.由于这种模型中假定接触应力沿接触界面为线性分布,从而得到的接触界面应力分布往往出现跳跃等非光滑性特征,该文对此进行了改进,采用具有高阶光滑性的非线性函数建立了能够考虑界面上接触应力非线性分布的接触力元模式,以期合理地揭示多体系统中界面的接触特性.对某一典型算例进行了数值计算,通过与大型通用非线性有限元结构分析软件ABASQUS的计算结果对比,验证了所建议计算模型的合理性与有效性.两种方法计算得到的界面接触对上的接触力基本相同;而由于采用的应力分布模式的假定不同,接触应力有所差别,由于在该文计算模型中接触对上的接触应力是按照未知量直接求得的,因此按照所建议的非线性接触力元模式所得到的接触应力更为合理. 相似文献
8.
基于无梯度思想,针对弹性接触问题中存在的应力集中问题提出了一种形状优化方法.研究发现:通过改变接触面和非接触面形状的方法,均能够有效地减轻弹性接触面上的接触应力集中.结合 ABAQUS 有限元分析软件,直接变动有限元模型中的接触面或非接触面单元节点的位置,进而改变优化边界的形状,最终达到减小接触面上应力集中的目的.通过两个优化算例分别展示了所提出的方法在处理二维和三维弹性接触问题中的可行性.算例结果表明:优化后,接触应力值分布在一个预定的区间内,接触面上的集中应力得到了显著的优化.本方法为处理工程接触优化问题提供了新的思路. 相似文献
9.
10.
基于所有接触面间光滑的假设,研究了同时受压的功能梯度层与弹性层间的单退让平面接触问题.假设功能梯度层是各向同性的非均匀材料,其剪切模量按照指数函数形式变化.利用Fourier积分变换把问题转化为求解奇异积分方程.然后利用Gauss-Chebyshev求积公式和迭代法得到下层接触应力和退让接触半径的数值解.最后在数值算例中,分别讨论了两层间的厚度比值,功能梯度层的硬度参数,以及上层接触半径对退让接触半径与下层接触应力的影响. 相似文献
11.
12.
四辊轧机辊系变形分析的有限元方法 总被引:14,自引:0,他引:14
采用有限元方法求解四辊轧机辊系变形问题,由于在工作辊及支承辊之间存在着未知接触压力和位移因而该问题无法用简单方法求解;根据辊系变形与受力的特殊性对方程进行变换可解出辊系各点位移,从而实现对辊系变形及辊缝形状进行较为准确的预报及控制。 相似文献
13.
The mill roller bearing is made up of an internal ring, middle rolls and an external ring, the analysis of which is a multi-bodies
contact problem. In this paper, based on the three-dimensional elastic contact BEM without friction, and using the structural
characteristics of roller bearings, middle rolls are described by elastic plate units of different shapes, which is placed
on the internal ring. The discontinuous traction problem of the contact element can be dealt with by the traction sub-element
method. Therefore the contact problem can be changed from one of multi-bodies to one of two-bodies. As an elastic deformation
of the plate element, it can be calculated by an elastic contact formula and is regarded as an equivalent gap to be put into
the total matrix equality. The face-to-face contact condition of displacement and traction on the element will serve as the
convergence judging condition. So convergence solution can be obtained before any geometry inconsistent on the contact element
may take place. Therefore, the three-dimensional distribution of load of the mill roller bearing can be achieved. It has been
proved that the calculating model of this method is visualized and simple, has fast convergence solution and higher accuracy,
making it an effective numerical method of designing and analyzing load characteristics of the mill roller bearing.
Project supported by the National Natural Science Foundation of China (50075075). 相似文献
14.
15.
An analytical model is presented for determining surface residual stress using continuous indentation. The elastic residual
stress is assumed to have no influence on contact area or hardness and to be uniform over a volume that is several times larger
than the indentation mark. A step-by-step analysis for the residual-stress-induced load difference at a given depth is outlined
here and such concepts as stress interaction, stress-sensitive contact morphology, and reversible contact recoveries during
a stress relaxation are described. Finally, the proposed method is applied to the interpretation of the continuous indentation
results obtained from an SS400 steel beam in which controlled bending stresses are generated. The stress estimated, however,
showed a high scatter due to plastic pile-up deformation. When the optically measured contact area is used as an alternative
of the contact area calculated from the unloading curve, the re-evaluated stress agrees well with the already known applied
stress. 相似文献
16.
17.
The coupling of the local contact problems between the components and the deformation of the components in the mechanical system were discovered. A series of coordinate systems have been founded to describe the mechanical system with the contact proble.ms. The method of isolating the boundary of contact body from others has been used to describe the constraint between the contacting points. A more generalized static mechanics model of the mechanical system with the contact problems has been founded through the principle of virtual work, As an application, the model was used to study the multi-teeth engagement problems in the inner meshed planet gear systems. The stress distribution of contact gears was got. A test has verified that the static contact model and the computational method are right. 相似文献
18.
Y. M. Tsai 《Journal of Elasticity》1986,16(2):179-188
The symmetrical problem of the contact between a spherical indenter and a thick transversely isotropic plate is solved using the techniques of the Hankel transform. Solutions are written as the sums of the associated half-space solution and plate thickness effect terms. The normalized normal contact stress and the surface radial stress are obtained and calculated numerically for both composite materials and metallic substances. The example materials give both real and complex characteristic roots. A general method of calculation is described to determine the maximum tensile radial stress and the maximum compressive normal contact stress.The plate thickness effects on the contact stress and on the tensile radial stress are shown to be increasingly important with decreasing thickness. The effects that the material anisotropy has on the magnification of the contact stress and the maximum tensile radial stress are clearly revealed in the numerical results presented. The effects of material anisotropy for the composite are compared to those for the metallic substances. 相似文献
19.
Normal and tangential stresses acting over a contact interface of a tire driven on dry sand were investigated to expand the applicability of our model incorporating 2D FE–DEM with proportional–integral–derivative (PID) control. A simple averaging method for contact reaction was introduced: computational segments were defined over the lower half part of the tire circumference that translates without rotation with the tire; then the contact stresses were calculated segment by segment. For the analysis, it was assumed that the tire was in rigid contact mode and that it would travel on the model sand terrain in stationary condition. The integration of normal and tangential contact stresses with respect to the angle of rotation was then applied to calculate the vertical contact load, gross tractive effort, net traction, and running resistance of the tire by parametric (or semi-empirical) analysis. The result of tractive performance obtained through the parametric analysis was found to be similar to the result of tractive performance obtained directly using FE–DEM analysis. A forward shift of the consistent angle of rotation for maximum normal contact stress and that for maximum tangential contact stress with the increase of slip from 22% was also observed in the FE–DEM result. 相似文献