共查询到19条相似文献,搜索用时 109 毫秒
1.
结合面的建模是结合面特征参数识别的关键问题.结合面建模时,分别用传统方法(基于弹簧-阻尼单元)和改进方法(基于接触单元和弹簧-阳尼单元)进行建模.根据两种等效模型,分别建立CK1632数控机床床身与底座固定结合面的有限元模型,用有限元分析软件ANSYS10.0进行模态分析,同时进行结合面参数的优化设计,先优化出刚度,再优化出阻尼值.模态振型分析的结果表明,基于接触单元及弹簧-阻尼单元的结合面模型比较合理.利用ANSYS的命令流输入方法计算出结合面的参数识别结果.这对机床整机动态特性的分析和优化设计具有重要意义. 相似文献
2.
3.
4.
机械结构中螺栓结合面动力学建模的准确性会直接影响其固有频率的准确性。通过计算模态分析与实验模态分析,以某床身螺栓结合面为例,对比分析了弹簧阻尼单元法与虚拟材料法等效螺栓结合面动力学模型,发现运用虚拟材料法等效螺栓结合面动力学模型准确性更高。 相似文献
5.
6.
7.
8.
针对考虑粗糙度影响的螺栓连接结构动态特性建模问题,建立了由弹簧-阻尼模型代替粗糙表面结合面的螺栓连接新模型,该模型综合考虑了螺栓、垫片、粗糙结合面等多种因素对振动特性的影响,纠正了以往模型不考虑表面粗糙度对振动频率的影响的弊端,更符合真实情况.该模型基于机械表面几何分形理论,得到结合面刚度特性计算公式.基于有限元接触分析结果确定弹簧-阻尼模型弹簧的布局域,同时研究了弹簧布局数量对振动特性的影响.实验结果显示,方法结果与实验结果非常接近,说明方法有效. 相似文献
9.
轮盘-轴组件的结合面特性对转子静动特性有着重要的影响,并且螺栓紧固质量是其中重要因素之一。本文以某燃机轮盘-轴组件为研究对象,采用弹簧阻尼单元等效处理结合面的螺栓连接,建立组件整体有限元模型。然后,基于吉村允孝的结合面等效刚度计算理论,提取试验测得的轮盘-轴组件结合面的面压参数,对等效模型中的弹簧阻尼单元各向刚度进行校准。对计算结果进行对比分析,并结合了模态测试的振型和固有频率数据,结果表明,该等效模型能够很好地模拟螺栓连接特性对轮盘-轴组件动态特性的影响。最后,基于该等效模型计算分析了螺栓连接的等效连接刚度大小和离散度对组件动态特性的影响规律。 相似文献
10.
考虑摩擦因素影响的结合面切向接触阻尼分形预估模型及其仿真 总被引:5,自引:0,他引:5
为准确计入结合面表面微观形貌对结合面的影响,提出结合面的“固-隙-固”接触模型。基于该接触模型和接触分形理论以及赫兹理论,建立考虑摩擦因素影响的结合面切向接触阻尼的分形预估模型,并通过数值仿真研究揭示有关参数对结合面切向接触阻尼的影响,为后续结合面动力学建模和动力学特性分析做准备。仿真分析结果表明:结合面的切向接触阻尼随结合面实际接触面积的增大而增大;随结合面法向载荷的增大而减小;随结合面间摩擦因数的增大而趋于恒定;实际接触面积影响cte*-μ曲线转折点(即临界摩擦因数μc)的位置,随着实际接触面积的增大,临界摩擦因数μc亦同时增大;不同的分形维数取值,尤其是分形维数取值在临界值(D=1.55)的两侧时,结合面间的接触行为存在较大差异。 相似文献
11.
基于材料弹塑性变形理论,采用激光测量仪测取零件表面微观形貌数据,使用小波对测量数据进行处理,提取不同层次的粗糙度,利用有限元分析软件ANSYS及其APDL工具,建立真实粗糙表面不同尺度上的微观接触参数化有限元模型,仿真分析了粗糙表面接触的弹塑性变形全过程。提出了基于ANSYS重启动分析、网格重划的多载荷步求解算法,以解决有限元微观接触分析过程中的网格畸变问题。通过通用后处理模块/POST1,提取了有限元分析结果文件中的真实接触面积、接触载荷、接触微凸体个数等接触参数,分析了多种不同粗糙度表面相互接触时接触参数的关系,以及不同尺度的粗糙面对接触参数的影响,为研究结合面的接触机理和连接性能提供了方法。 相似文献
12.
建立了一种用于磨床砂轮破裂后防护罩变形过程分析的有限元模型。采用显式时间积分格式,磨床安全防护罩采用一点积分的4节点双线性壳单元。材料服从等向强化塑性准则。砂轮、法兰、主轴及支座采用一点积分的8节点实体单元。接触搜寻采用主从面法,接触力由罚参数计算,摩擦力由经典摩擦定律决定,砂漏控制采用前置参数方法。采用间接方法验证了本文力学模型的正确性。实例表明,本文的模型切实可行。 相似文献
13.
A surface contact model that takes account of flattening, roughening and tool elastic microwedge effects on workpiece surface is developed. The model can be implemented in FEM codes to predict the final surface qualities of the products in metal forming. As an example, the proposed model has been combined with a membrane finite element code of sheet metal forming process to predict the contact area ratio, surface roughness and mean asperity spacing. Numerical results showed good agreement with the experiments. 相似文献
14.
基于统计学方法,Greenwood和Tripp(GT模型)提出双粗糙平面法向接触(双粗模型)可以等效为单粗糙平面与刚性平板之间的接触(单粗模型),但这种等效处理缺乏对接触应力场分析以及材料硬化的考虑。为进一步研究GT模型,基于高斯粗糙表面数字化表征,通过控制自相关长度和滤波方法,得到双粗糙平面及其等效单粗糙平面;借助有限元软件ABAQUS对2组模型法向接触进行建模及分析。结果表明:2组模型预测的接触刚度和接触面积符合较好,但接触压力与接触面积关系存在差异;2组模型预测的等效应力和接触压强的应力幅值以及云图的分布区域大致相近,但双粗模型由于存在大量微凸体侧接触,弱化接触状态以及材料硬化,因而应力幅值偏低。 相似文献
15.
Xiang Zhang Klaus Kneupner Bernd Kuhlenkötter 《The International Journal of Advanced Manufacturing Technology》2006,27(7-8):726-732
Industrial robots have been introduced to the belt grinding of free-form surfaces in order to obtain high-quality products
and high-efficiency. One of the critical problems of high-precision belt grinding is to compute the force distribution in
the contact area between the workpiece and elastic grinding wheel. The finite element method (FEM) is the traditional way
to solve such a contact problem. However, the FEM model is too time-consuming. Normally, a single calculation takes several
minutes on a powerful PC, which is unacceptable for real-time simulations and on-line robot control. A new model based on
a neural network (NN) technique is developed instead of the FEM model to calculate the force distribution. The new model approximates
the old FEM model with an acceptable tolerance but can be executed much faster than FEM model. With this new model, real-time
simulation and on-line robot control of grinding processes can be further conducted. 相似文献
16.
AbstractThe objective of this study is to investigate the effects of the contamination of lubricants on denting in rolling element bearings. A dynamic, explicit finite element model (FEM) is developed to reproduce and analyse the elastic–plastic response of the surfaces when a spherical particle passes through a heavily loaded contact area. To cope with mesh distortion issues due to the high deformation of the debris along the process, a novel Eulerian approach is used to model the particle. A parametric study is conducted with the coupled Euler-Lagrange (CEL) model to determine the influence of the debris size, bearing loading, friction coefficient, material properties, and relative sliding between the surfaces on the indentation features. The FEM results emphasize the major role of the material properties of the three bodies on the dent geometry, pointing out that the softer surface undergoes more severe damage. In the same way, the protection of one of the surfaces by a specific heat treatment such as nitriding leads to more severe damage on the other one. The results exhibit a direct link between the particle and dent sizes. For large particles, a change in the dent geometry is observed when the deformed particle size overcomes the contact width because the particle is no longer enclosed in the contact and is therefore spread more easily. The model reproduces two important aspects of the indentation in rolling element bearings, which are the asymmetry of the dent and the residual stresses distribution, providing interesting prospects for future work on the fatigue failure caused by these defects. 相似文献
17.
18.
采用三维设计软件SolidWorks建立数控平面磨床床身 ,导入ANSYS软件后进行三维有限元分析 ,并与以往的二维有限元分析计算作比较 ,为床身的改造和优化提供了重要的依据 相似文献
19.
An enriched finite element algorithm for numerical computation of contact friction problems 总被引:2,自引:0,他引:2
In this paper, the extended finite element method (XFEM) is employed to model the presence of discontinuities caused by frictional contact. The method is used in modeling strong discontinuity within a standard finite element framework. In extended finite element method (XFEM) technique, the special functions are included in standard FEM to simulate discontinuity without considering the boundary conditions in meshing the domain. In this study, the classical finite element approximation is enriched by applying additional terms to simulate the frictional behavior of contact between two bodies. These terms, which are included for enrichment of nodal displacements, depend on the contact condition between two surfaces. The partition of unity method is applied to discretize the contact area with triangular sub-elements whose Gauss points are used for integration of the domain of elements. Finally, numerical examples are presented to demonstrate the applicability of the XFEM in modeling of frictional contact behavior. 相似文献