胶印机匀墨系统运动及变形特性分析

为分析胶印机匀墨系统的运动和变形,利用ANSYS建立了匀墨系统中串墨辊和匀墨辊的模型,分析了匀墨辊运动、变形、剪切应力、正应力的特点及影响因素。分析结果显示：匀墨辊运动主要受串墨辊转速和串墨辊窜动量的影响;匀墨辊正应力主要受其硬度的影响;匀墨辊剪切应力主要受其硬度和两墨辊间摩擦因数的影响;匀墨辊变形主要受其硬度、串墨辊窜动量、串墨辊转速的影响。     

流体密封的磁流变流体粘度特性分析

叙述了流体密封中磁流变流体(Magnetorbelogical Fluid，简称MRF)的磁变效应。介绍了纳米Fe3O4磁流变流体的粘度特性实验，并对磁流变流体的粘度特性进行分析。为磁流变流体在流体密封中的应用提供参考依据。     

慎用运动粘性系数比较流体的粘性大小

粘性是流体的一种物理性质,其大小代表了流体流动的难易程度。通常用动力粘性系数的数值衡量流体粘性的大小。而运动粘性系数与动力粘性系数有本质的区别,只能代表流体粘性的相对大小,若用来比较不同流体之间的粘性就会引起严重的错误。     

移动槽轮机构的运动特性与动力特性分析

对移动槽轮机构作了运动分析和动力分析。在阐明其运动特征和动力特征的基础上，导出了便于设计参考的动力常数τ，并绘制了有关线图。为正确设计移动槽轮机构提供了依据。     

流体应力方向、运动方程、广义应力公式综述

目前流体力学教材上,关于流体中应力分量的定义、微元六面体上应力分量方向的假设方法各不相同,与此相对应,用应力表示的流体运动微分方程及广义应力公式也必须采取不同形式。若上述对应关系搞错势必得出错误结果。这种问题可能被忽视,为解决此问题,对流体中应力分量的定义、应力方向假设方法、用应力表示的流体运动微分方程及广义应力公式进行了分析和归纳总结,用具体例子加以说明。并给出如何根据应力计算结果的正负判断应力方向的方法。     

慎用运动粘性系数比较流体的粘性大小

粘性是流体的一种物理性质，其大小代表了流体流动的难易程度。通常用动力粘性系数的数值衡量流体粘性的大小。而运动粘性系数与动力粘性系数有本质的区别，只能代表流体粘性的相对大小，若用来比较不同流体之间的粘性就会引起严重的错误。     

单叶片推进器及其运动特性

提出了一种新型的流体推进器——单叶片推进器,通过对叶片的运动学和负载的分析,建立了该推进器的运动方程。基于ADAMS环境,建立了单叶片推进器的虚拟样机,并进行了推进器系统的动力学仿真。仿真分析表明:单叶片推进器能够在设定转速下稳定运行;有效推力是脉动变化的,但在稳定转速下,有效推力的幅值和频率是稳定的,可以产生稳定的推动效果。     

一体化预制泵站的流体分析

基于计算流体动力学方法,对一体化预制泵站进行流体分析。对一体化预制泵站进行三维建模,抽取全流道水域,对水域进行网格划分,采用RNG k-ε模型对湍流进行求解,并对数值模拟结果进行后处理。基于数值模拟结果,分别在筒体内部不同位置设置截面,查看流线和矢量分布,从而对一体化预制泵站的运行流态进行评估。分析结果表明,运行时启用两台泵,筒体内部流动状态达到最佳,可以最大程度提高泵机组的运行效率和稳定性。     

曲柄连杆机构运动及动力特性分析

曲柄连杆机构在高温高压条件下作变速运动,因此它在工作中的受力极其复杂。本文针对柴油机曲柄连杆机构进行了运动和动力特性分析,得出了机构中主要零件的运动规律和所承受的力厦力矩。从而为设计曲柄连杆机构和减小发动机振动提供了重要的依据。     

分析规模超临界流体萃取技术

介绍了一种很有发展前途的样品制备方法－分析规模的超临界流体萃取技术基础和仪器进展，其特点是快速，方便高效，无污染，并能与多种分析技术联用，已在环保分析，药物分析等方面显示了广阔的应用前景。引用主要文献２４篇。     

基于有限元对箱体装夹变形的分析研究与实践

通过采用有限元技术,对箱体加工过程中的铣削力、夹紧力、夹紧布局对发动机箱体加工变形的影响进行分析,以及对相应的变形控制技术进行研究。在优化的夹紧布局下通过变化夹紧力,研究夹紧力大小对工件加工变形的影响,最终得出夹紧布局及夹紧力对工件加工变形的影响规律,获得了较奸的夹紧布局和恰当的夹紧力参数,为大型框架式壳体件加工质量提供了可靠保证。     

四杆张拉整体单元的弯曲变形

为了扩大张拉整体的内部空间,实现展开前空间占用小,展开后内部空间的有效利用率高,对张拉整体轴向折叠方式及折展特性进行了研究.根据张拉整体的理论基础,介绍了节点矩阵、连接矩阵和构件矩阵,分析了张拉整体轴向折叠的意义以及存在的问题,并介绍了两种张拉整体沿轴向折叠的方法.在这两种折叠方式的基础上提出弯杆张拉整体,并给出弯杆张...     

铝合金薄壁件侧壁加工变形有限元分析

在分析现有文献有关铣削加工力学模型的基础上,利用有限元分析软件ANSYS10.0,针对铝合金薄壁板进行铣削力求值及变形分析.对薄壁件加工变形有限元分析过程进行关键技术讨论,为实际切削做出理论性的探索.     

立辊轧机机架强度和变形的有限元分析

对某厂新改造的立辊轧机机架进行了有限元分析,得出了符合实际情况的应力场和变形状况,根据该轧机全液压压下方式的特点,对机架立柱和横梁区域进行了重点分析,得出结论机架的强度和刚度完全可以满足生产的需要,为更深入研究该立辊轧机提供了可靠的依据.     

离合器摩擦片热变形有限元分析

建立了摩擦离合器接合过程热分析数学模型,并利用有限元技术对离合器外摩擦片进行了热变形分析,结果显示离合器外摩擦片在一定工况条件下会发生翘曲变形,与实际外摩擦片变形情况一致,证明了热变形分析的正确性.该分析也为摩擦离合器安全工作提供了一定的理论依据.     

Finite element simulation of deformation processes of micro-components

The aim of this paper is to improve the understanding of deformation of micro medical needle and thread during assembly and then to develop an economical and flexible deformation method. Therefore, the swaging process is computationally simulated with the finite element method in this paper. A commercially available explicit nonlinear finite element analysis code, LS-Dyna, is used to model the 3-D deformation and contact problem. As the firmness of the assembly on the needle depends on the contact force and friction, the contact and the slide between the needle and thread are taken into account in the simulation. The general surface-to-surface contact algorithm (STS) is used to simulate the contact. The paper provides an insight into the deformation of the micro products.     

万向轮螺旋滚子受压变形的有限元分析

根据螺旋滚子曲面重构得到的数据,利用Pro/E软件进行了三维实体建模,在ANSYS软件中建立滚子的有限元模型,并进行受力变形的有限元仿真,得到了变形图和位移云图.对仿真结果进行了分析,找到了滚子在轴线方向和垂直方向的最大位移处,为合理选材提供了依据.结果证明,螺旋滚子在受压变形下,实际轮廓线会偏离理论理想轮廓线.为了使全方位移动平台运行平稳精确,需要在滚子设计制造时,考虑受力变形的影响.分析结果对于提高平台的运动精度和承载力,使其更好地推广应用具有重要意义.     

Inclusion of elastic deformation in rigid-plastic finite element analysis

A rigid-plastic finite element method combined with the effect of elastic deformation is proposed. In the present method, elastically and elastic-plastically deforming elements are mixed with rigid-plastically deforming elements in the deforming material. In this formulation based on an implicit scheme, the nodal forces for the rigid-plastic elements are equilibrated with those for the elastic and elastic-plastic elements at the end of each deformation step. The nodal forces for the elastic and elastic-plastic elements are derived by considering the effect of rigid-body rotation during deformation increment. The elastic-plastic element is transformed into the rigid-plastic one during the loading when the elastic strain increment is small. The reverse transformation is carried out in the unloading. This leads to a comparatively small computing time and the improvement of the calculated results. Plane-strain bending of a plate with a round punch is simulated by the present method under a mixed condition of elastic, elastic-plastic and rigid-plastic elements in the plate. Deformation behaviour in early stages of bending is successfully calculated. The calculated amounts of springback are in reasonable agreement with the experimental ones for aluminium plates because the stress distribution in the elastic regions without achieving yielding around the edges of the plate is taken into consideration.     

自动铆接过程中铆钉变形的有限元分析

飞机薄壁结构件铆接过程中产生的装配变形不仅在装配体中留下残余应力和挤压裂纹,而且增加连接结构的脆性,降低飞机的疲劳寿命,给飞机的精准装配和装配寿命造成巨大的威胁.用ANAYS软件,以铝合金材料(2A10)建立铆钉有限元模型,模拟铆钉应力、应变的变化过程及变形情况,反求出精确的压铆力.为自动钻铆过程中压铆力的施加与控制提供参考,对探索铆钉变形修正方法、控制装配误差有积极意义.     

Finite element analysis and experimental investigation on deformation mechanism of non-axisymmetric tube spinning

This paper developed 3D elastoplastic finite element analysis (FEA) models to investigate non-axisymmetric tubes neck spinning. The three-roller mandreless neck spinning process was simulated by commercial FEA software, MSC. Marc. The distribution of the transient von Mises stresses in the contact zone between the roller and the blank, and the equivalent plastic strains after spinning were obtained. The locations and causes of fractures were analyzed. The thickness distribution of the spun workpiece was investigated numerically and experimentally. It shows that during 3D non-axisymmetric tubes spinning, diametral elongation and fractures mostly occur at the opening end of workpiece, which considered as the primary location of defects. Fractures may also occur easily at the initial spinning area, which may be considered a secondary location of defects. The distributions of equivalent stresses and strains are non-uniform during both offset and oblique 3D non-axisymmetric tubes spinning. The maximum stress and strain values occur at the location where the biggest offset or inclination is induced, while the minimum values occur at the opposite location of 180° away from the maximum values. For the oblique tube, however, the strain distribution changes gradually along the axial direction, which is different from that of the offset tube. Thinning occurs during forward path spinning and thickening occurs during backward path spinning. Therefore, for multipath neck spinning processes, forward and backward paths should be applied alternately to avoid excessive thinning or thickening of workpiece.