大功率膜片联轴器扭转刚度计算研究

作为轴系扭振分析中最重要的参数之一,联轴器扭转刚度是联轴器良好特性必须考虑的基本指标;本文应用有限元法对传递较大转矩的膜片联轴器的膜片应力做出了详细分析,指出了膜片应力分布状况;并对其扭转刚度作了计算分析,计算结果与国外同类型产品非常接近.论文结果为研发大功率膜片联轴器提供了重要参考.     

Analysis of rectangular laminated composite plates via FSDT meshless method

A meshless approach based on the reproducing kernel particle method is developed for the flexural, free vibration and buckling analysis of laminated composite plates. In this approach, the first-order shear deformation theory (FSDT) is employed and the displacement shape functions are constructed using the reproducing kernel approximation satisfying the consistency conditions. The essential boundary conditions are enforced by a singular kernel method. Numerical examples involving various boundary conditions are solved to demonstrate the validity of the proposed method. Comparison of results with the exact and other known solutions in the literature suggests that the meshless approach yields an effective solution method for laminated composite plates.     

Free vibration of a laminated composite shell of revolution: Effects of shear non-linearity

Effects of shear non-linearity on free vibration of a laminated composite shell of revolution are investigated using a semi-analytical method based on the Reissner–Mindlin shell theory. The coupling between symmetric and anti-symmetric vibration modes of the shell is considered in the shear deformable shell element employed in this study. The Hahn–Tsai non-linearly elastic shear stress–shear strain relation is adopted. Numerical examples are given for laminated composite circular cylindrical and conical shells with various boundary conditions. The numerical results indicate that shear non-linearity may reduce significantly the fundamental frequencies of cross-ply composite shells of revolution.     

250 t高速动平衡机摆架的动刚度分析

高速动平衡机摆架的动力学性能直接影响动平衡试验的准确性及安全性。采用三维有限元法建立某公司250 t高速动平衡机摆架的计算模型,并对其动刚度进行计算分析,且与试验值进行比较。在此基础上计算4种主刚度杆改进方案下摆架的动刚度特性,分析主刚度杆的刚度对高速动平衡机摆架的动刚度曲线的影响。结果表明,计算所得摆架的动刚度曲线与实测值吻合较好,该计算模型接近实际情况。主刚度杆的结构尺寸及材料的弹性模量的增大均会使摆架的动刚度增大,适当地改变主刚度杆的结构尺寸及材料特性,可使高速动平衡机摆架满足大质量转子的高速动平衡试验要求。通过主刚度杆的改进并不能使摆架的动刚度随转速变化的曲线趋于平缓。     

基于ANSYS的闩体刚强度有限元分析

闩体的刚度和强度必须满足设计要求。用有限元法对复杂结构件进行力学性能分析是非常有效的方法。采用ANSYS软件对闩体进行了刚度和强度分析,得出了有用的结论,可供相关设计借鉴。     

一种夹层板结构车厢的有限元简化模型及模态分析

以某型车的车厢夹层复合板结构为例,研究了夹层板结构的有限元建模方法,建立了车厢的有限元简化模型并进行了模态分析。与传统上使用的板梁单元相比,单元自由度数减少了66.7%,大大缩短了分析时间,提高了计算效率。     

MARC有限元分析在钢板弹簧设计中的应用

应用MARC有限元分析技术,不需要任何假设,尽量考虑到钢板弹簧实际受力的情况,实现比传统设计方法更为精确的计算。较为精确地计算出组装后各片板簧的预应力、共同曲率、U形螺栓夹紧后的总成弧高、总成刚度及指定载荷下的位移、应力和应变值。     

Dynamic stability of cross-ply laminated composite cylindrical shells

The dynamic stability of thin, laminated cylindrical shells under combined static and periodic axial forces is studied using Love’s classical theory of thin shells. A normal-mode expansion of the equations of motion yields a system of Mathieu–Hill equations. Bolotin’s method is then employed to obtain the dynamic instability regions. The present study examines the dynamic stability of antisymmetric cross-ply circular, cylindrical shells of different lamination schemes. The effect of the magnitude of the axial load on the instability regions is also examined.     

一种结合部法向刚度的预估方法

提出一种结合部法向刚度的预估方法.通过表面形貌测量仪获取粗糙表面的轮廓数据,拟合生成粗糙表面轮廓曲线,在此基础上建立考虑摩擦的二维粗糙表面的有限元弹塑性接触模型,用罚函数法计算压力在0～0.8 MPa的加载过程中接触层的应力、位移和接触面积.计算结果表明,粗糙表面真实的接触面积在低载荷下快速增大,高载荷下的增大速度很缓...     

Free vibration of laminated composite plates using two variable refined plate theory

Free vibration of laminated composite plates using two variable refined plate theory is presented in this paper. The theory accounts for parabolic distribution of the transverse shear strains through the plate thickness, and satisfies the zero traction boundary conditions on the surfaces of the plate without using shear correction factors. Equations of motion are derived from the Hamilton's principle. The Navier technique is employed to obtain the closed-form solutions of antisymmetric cross-ply and angle-ply laminates. Numerical results obtained using present theory are compared with three-dimensional elasticity solutions and those computed using the first-order and the other higher-order theories. It can be concluded that the proposed theory is not only accurate but also efficient in predicting the natural frequencies of laminated composite plates.     

单刚矩阵计算用神经网络结构的实验确定

提出将BP网络与函数型网络相结合用于有限元单元刚度矩阵的实时计算,给出了网络结构的设计依据,对不同阶数输入向量的网络的收敛速度进行了对比分析,为网络输入参数数目的确定提供了参考。     

轻型客车车身结构刚度与模态的有限元分析

建立了某轻型客车车身结构详细的有限元模型。分析了符合轻量化设计要求的新型的半承载式车身结构的刚度与模态。通过研究主要零部件对结构扭转刚度及低阶模态的影响 ,明确了车身结构设计中的主要影响因素。为轻型客车车身设计提供了参考依据     

Prediction of actuating displacement in a piezoelectric composite actuator with a thin sandwiched PZT plate by a finite element simulation

This paper presents the evaluation of a plate-type piezoelectric composite actuator (PCA) with a thin sandwiched plate having four kinds of lay-up configurations by analyzing the flexural displacement For this, a three-dimensional finite element simulation considering the thermal deformation effect of PCA during manufacturing is conducted based on a thermal analogy model. The distribution of residual thermal stresses and the dome height caused by the mismatch in coefficient of thermal expansion (CTE) between the layers of PCA are predicted with the aid of a classical laminated plate theory (CLPT). Results of finite element analyses have revealed that the flexural displacement of PCA subjected to electric fields is considerably affected by the variation of lay-up configuration, the thickness of an embedded PZT wafer and boundary conditions. In particular, as the thickness of the PZT ceramic increases, the bending stiffhess of PCA increases faster than the actuation distance does, which leads to the overall reduction in flexural displacement. It is therefore suggested that the electrically induced flexural displacement of unimorph-type PCA depends more on the bending stiffhess than on the actuation distance.     

叠片式双钩强度的有限元分析研究

炼钢车间的铁水罐倾倒铁水的过程中的倾翻吊钩是一个特殊的双吊钩,传统的方法是采用锻造的方法生产.应用传统的强度校核方法研究双钩的工作应力分布,然后采用有限元分析对拟采用的叠片式结构的强度进行了三种状态下的强度计算与分析,结果表明采用叠片式铆接双钩完全可以代替传统的锻造双钩,为大型单件结构的生产工艺改进进行了有益的探索.     

风力发电机齿轮箱扭力轴的疲劳分析

应用有限单元法,对风力发电机齿轮箱中的扭力轴的进行了疲劳寿命分析.利用Solid-works和ANSYS-Workbench软件建立了扭力轴的三维有限元模型,并在ANSYS-Workbench中对轴进行了结构疲劳分析,证明其疲劳寿命符合设计要求.     

UWQ40型板式楔横轧机模板刚度的三维有限元分析

板式楔横轧机可以辊轧精度高、稳定性好的轴类零件 ,但刚度较差且主要由模板变形引起 ,模板的刚度性能在很大程度上影响着产品质量。本文采用弹性有限元法 ,以立式UWQ4 0型板式楔横轧机模板为研究对象 ,对其进行了刚度计算和分析 ,提出了改进方法 ,得到了模板的最大变形量及等效应力分布等信息 ,同时对模板刚度和变形进行了改进前、后的对比分析。结果显示 :板式楔横轧机结构改进后 ,在最大轧制力作用下模板的最大变形量从改进前的 3.7× 10 -2 mm降低到 2 .89× 10 -2 mm ;改进后模板装置的材料节约了近 17.1%。最后 ,为进一步提高板式楔横轧机的模板刚度提出了一些建议。     

Analytical solutions for bending analysis of rectangular laminated plates with arbitrary lamination and boundary conditions

The intent of the present study is to employ the extended Kantorovich method for semi-analytical solutions of laminated composite plates with arbitrary lamination and boundary conditions subjected to transverse loads. The method based on separation of spatial variables of displacement field components. Within the displacement field of a first-order shear deformation theory, a laminated plate theory is developed. Using the principle of minimum total potential energy, two systems of coupled ordinary differential equations with constant coefficients are obtained. The equations are solved analytically by using the state-space approach. The results obtained are compared with the Levy-type solutions of cross-ply and antisymmetric angle-ply laminates with various admissible boundary conditions to verify the validity and accuracy of the present theory. Also, for other laminations and boundary conditions that there exist no Levy-type solutions the present results are compared with those obtained by other investigators and finite element method. It is found that the present results have very good agreements with those obtained by other methods. This paper was recommended for publication in revised form by Associate Editor Heoung Jae Chun Ali Mohammad Naserian Nik received his M.S. in Mechanical Engineering from Ferdowsi University of Mashhad, Iran, in 2006. Currently, he is a doctoral student at the Department of Mechanical Engineering, Ferdowsi University of Mashhad, Iran. His research interests are in the area of computational mechanics and nanobiotechnology. Masoud Tahani is currently an Associate Professor at the Department of Mechanical Engineering at Ferdowsi University of Mashhad, Iran. He received his B.S. in Mechanical Engineering from Ferdowsi University of Mashhad, Iran, in 1995. He then received his M.S. and Ph.D. degrees from Sharif University of Technology, Iran, in 1997 and 2003, respectively. Dr. Tahani’s research interests include design of structures using advanced composites, mechanics of anisotropic materials, smart materials and structures, mechanics of plates and shells and biomechanics.     

波纹管换热管刚度计算模型研究

波纹管换热器管板的设计中,一般都是将波纹管简化为相应规格的光管来进行计算.然而波纹管不同于光管,波纹管的轴向刚度比光管的轴向刚度小得多,造成其对管板的支撑与光管有明显不同,最终波纹管换热器管板的设计计算结果存在着很大的不确定性.文中从波纹管刚度的计算方法入手,用有限元方法计算出波纹管换热管刚度值,进而分析了不同尺寸参数对于波纹管刚度的影响,并在此基础上建立针对工程上常用规格的波纹管刚度计算模型,经参数关联后,该模型具备了较佳的波纹管刚度预测能力,从而为波纹管换热器管板的强度计算提供方便.     

具有横向裂纹转轴耦合刚度的数值模拟和实验研究

采用有限元和实验分析研究轴向、剪切、弯曲及扭转载荷耦合作用下,含裂纹转轴刚度随各种影响因素的变化规律.采用Dimarogonas法推导6×6维裂纹转轴有限元刚度矩阵.确定网格划分方案,同时考虑d/l、a/R以及加载点与裂纹的位置关系.模拟计算结果表明,随着裂纹深度的增大,ξ向无量纲刚度的变化最快;裂纹深度在3 mm～4 mm时,ξ向、η向的弯曲无量纲刚度差有峰值.随着裂纹细长比的增大,弯曲和轴向的耦合刚度降低.随着裂纹深度比增大,弯曲和轴向的耦合刚度增大.结果与实验结果比较表明,文中方法是正确有效的,且接近实验结果.     

Generalized buckling analysis of laminated plates with random material properties using stochastic finite elements

A generalized layer-wise stochastic finite element formulation is developed for the buckling analysis of both homogeneous and laminated plates with random material properties. The pre-buckled stresses are considered in the derivation of geometric stiffness matrix and the effect of variation in these stresses on the mean and coefficient of variation of buckling strength is studied. The mean buckling strength of plates under uniform stress assumption exactly matches with those reported in the literature. However, it is shown that the actual mean buckling strength of plates can be significantly different based on the pre-buckled stress analysis which depends on boundary constraints, principal material directions, aspect and thickness ratios of plates. The statistics of buckling strength is determined using a Taylor series expansion based mean centered first order perturbation technique. The stochastic finite element solutions obtained using layer-wise plate theory is also validated with analytical solutions presented in this paper. Parametric studies are conducted for different aspect ratios, ply orientations and boundary conditions.