冷锻厚壁加强三通有限元分析

本文介绍了对冷锻厚壁加强三通限元分析的方法和结果。分析结果表明三通满足强度设计要求，但是复杂工况条件下三通的母管与支管相贯肩部的应力值很大。所得结论为进一步改进三通设计提供了理论依据。     

有限元法在结构分析中的应用

主要介绍了有限元法的现状及发展趋势,有限元法的技术路线及有限元分析软件ANSYS。     

Buckling analysis of laminated composite rectangular plates reinforced by SWCNTs using analytical and finite element methods

In this paper, the buckling analysis of laminated composite plates reinforced by single-walled carbon nanotubes (SWCNTs) is carried out using an analytical approach as well as the finite element method. The developed model is based on the classical laminated plate theory (CLPT) and the third-order shear deformation theory for moderately thick laminated plates. The critical buckling loads for the symmetrical layup are determined for different support edges. The Mori-Tanaka method is employed to calculate the effective elastic modulus of composites having aligned oriented straight nanotubes. The effect of the agglomeration of the randomly oriented straight nanotubes on the critical buckling load is also analyzed. The results of analytical solution are compared and verified with the FEM calculations The critical buckling loads obtained by the finite element and the analytical methods for different layup and boundary conditions are in good agreement with each other. In this article, the effects of the carbon nanotubes (CNTs) orientation angle, the edge conditions, and the aspect ratio on the critical buckling load are also demonstrated using both the analytical and finite element methods.     

Elasto-plastic co-indentation analysis of a bounded solid using finite element method

The present investigation deals with the elastic and elasto-plastic finite element analyses of the simultaneous indentations of a bounded solid by two flat plane rigid smooth punches under plane-strain conditions. It also extends the earlier work of Meguid et al. [1], in which the present problem was investigated experimentally using etching techniques and theoretically using the upper-bound theorem. The extension of that work, reported herein, is devoted mainly to studying the effect of the interference ratio, the height and the strain-hardening characteristics of the bounded solid upon the plastic zone development, the indentation pressure-punch displacement relationships and the unloading residual stresses using the finite element method. Some of the results are compared with the earlier findings of Meguid et al. [1] of the same problem. The importance of the present contact problem is realised in many engineering applications, e.g. impact treatment processes, friction and wear, adhesion and surface finish studies.     

Suspension modeling and optimization using finite element analysis

A finite element based optimization software Altair OptiStruct is used to optimize the design of suspensions in hard disk drives. Topology optimization, topography optimization and combinations of both techniques are used to optimize a contact start-stop suspension with respect to torsion, bending and sway mode frequencies. The suspension, gimbal, slider and airbearing are modeled. The airbearing is modeled with linear springs to represent stiffness in the z-direction, pitch and roll. Modal analysis is compared to experimental resonance data to verify the model. The results show that improvements of more than 50% can be achieved with respect to increasing sway or torsional modes.     

Dynamic analysis of a car chassis frame using the finite element method

An automobile chassis structure has been analysed dynamically using the finite element method, and the results have been compared with those obtained experimentally. The first nine natural resonances of the frame up to 100 Hz have been examined.

Two basic methods of predicting the dynamic response have been used involving different computing techniques. Since computing costs are of prime importance in any practical application of the finite element method, the modes of operation of the programs have been briefly described and running times are compared for a number of structural idealizations.

The results presented show for a relatively simple structure that simple idealization concepts can give good results.     

高速动车组列车制动缸体ANSYS有限元分析

采用Pro/E对高速动车组列车制动缸进行了三维实体建模,并进行虚拟组件装配,利用ANSYS10.0软件对制动缸体进行有限元强度分析,计算结果表明最大应力出现在缸底与缸体连接处,此处由应力集中引起的,从整体看压应力大于拉应力.     

压缩机曲轴的有限元分析

为了研究曲轴的动力学特性,利用ANSYS软件的模态分析模块,采用了BLOCK LANCZONS算法对双拐曲轴进行了模态分析,求出了其前6阶固有频率和振型,并且计算出了曲轴的各阶临界转速,为了曲轴的优化设计、制造以及维修都提供了理论指导。     

过盈联接的有限元分析

介绍了过盈联接结构与原理,和传统计算方法。使用ADINA有限元软件对轴孔经常应用的过盈配合联接进行分析,通过有限元的模型建立,有限元单元类型的选择,有限元网格的划分,解题程序的控制和后置处理结果的分析,说明ADINA在过盈联接的分析中是完全适用的及其的精确性。     

盘式制动器的结构场有限元分析

首先探讨盘式制动器在制动过程中的摩擦接触和非线性动力学问题.具体的分析方法包括:摩擦接触算法,非线性有限元方法.按照制动盘与摩擦片的实际几何尺寸,建立了具有速度可变效应的三维瞬态结构应力有限元模型,利用非线性有限元方法,较真实地模拟了制动器的制动过程.通过以上分析得出制动过程的一些结构上的性能变化.将同相同制动条件下的实心盘式制动器和通风盘式制动器对比,得出通风盘式制动器在制动过程中的接触应力,各向位移等.     

Diametral compression test: validation using finite element analysis

The validation of the diametral disk compression test with a small flat ground and soft pad utilization has been established. The stress distribution was determined by the finite element analysis for a range of loading conditions. The results showed that for the case of a point load, the fracture is due to shear and compressive stresses at the loading point. The application of the diametral disk test for a flat ground, as well as the use of soft pads at loading regions were proposed and tested. The results showed that both grounds, flat areas and soft pads, have a significant effect on the stress distribution patterns and values in the compression disk test. The stress distributions obtained in both cases, as loading continued, are found to deviate immediately from the assumed ideal point load condition. The obtained results and data, particularly at the disk center, were manipulated in order to obtain a correction equation. Thus, the maximum tensile stress variations, at the center, with the different loading conditions over a wide range ratio of the width of the loading area to the diameter of 0.5 were recorded. Consequently, the stress differences from the ideal case (i.e., the point loading condition) were calculated and fitted with a correction equation. The use of this correction equation can be used to obtain accurate results of the diametral compression test.     

Multi-domain structural-acoustic coupling analysis using the finite element and boundary element techniques

A new approach to analyze the multi-domain acoustic system divided and enclosed by flexible structures is presented in this paper. The boundary element formulation of the Helmholtz integral equation is used for the internal fields and the finite element formulation for the structures surrounding the fields. We developed a numerical analysis program for the structural-acoustic coupling problems of the multi-domain system, in which boundary conditions such as the continuity of normal particle velocity and sound pressure in the structural interfaces between Field 1 and Field 2 are not needed. The validity of the numerical analysis program is verified by comparing the numerical results with the experimental ones. Example problems are included to investigate the characteristics of the coupled multi-domain system.     

Development of thermal models of footwear using finite element analysis

Thermal comfort is increasingly becoming a crucial factor to be considered in footwear design. The climate inside a shoe is controlled by thermal and moisture conditions and is crucial to attain comfort. Research undertaken has shown that thermal conditions play a dominant role in shoe climate. Development of thermal models that are capable of predicting in-shoe temperature distributions is an effective way forward to undertake extensive parametric studies to assist optimized design. In this paper, two-dimensional and three-dimensional thermal models of in-shoe climate were developed using finite element analysis through commercial code Abaqus. The thermal material properties of the upper shoe, sole, and air were considered. Dry heat flux from the foot was calculated on the basis of typical blood flow in the arteries on the foot. Using the thermal models developed, in-shoe temperatures were predicted to cover various locations for controlled ambient temperatures of 15, 25, and 35 degrees C respectively. The predicted temperatures were compared with multipoint measured temperatures through microsensor technology. Reasonably good correlation was obtained, with averaged errors of 6, 2, and 1.5 per cent, based on the averaged in-shoe temperature for the above three ambient temperatures. The models can be further used to help design shoes with optimized thermal comfort.     

Vibration analysis of delaminated composite beams and plates using a higher-order finite element

In order to analyze the vibration response of delaminated composite plates of moderate thickness, a FEM model based on a simple higher-order plate theory, which can satisfy the zero transverse shear strain condition on the top and bottom surfaces of plates, has been proposed in this paper. To set up a C⁰-type FEM model, two artificial variables have been introduced in the displacement field to avoid the higher-order derivatives in the higher-order plate theory. The corresponding constraint conditions from the two artificial variables have been enforced effectively through the penalty function method using the reduced integration scheme within the element area. Furthermore, the implementation of displacement continuity conditions at the delamination front has been described using the present FEM theory. Various examples studied in many previous researches have been employed to verify the justification, accuracy and efficiency of the present FEM model. The influences of delamination on the vibration characteristic of composite laminates have been investigated. Especially the variation of ‘curvature of vibration mode’ (i.e., the second-order differential of deflections in vibration mode) caused by delamination has been studied in detail to provide valuable information for the possible identification of delamination. Furthermore, two approaches have been investigated to detect a delamination in laminates by employing this information.     

Fast visualization of finite element analysis results using multiresolution meshes

Journal of Mechanical Science and Technology - This paper presents a new method for fast visualization of finite element analysis results using multiresolution meshes. The original mesh of a finite...     

Process parameter selection for the consolidation of continuous fiber reinforced composites using finite element simulations

The foil/fiber/foil process is one of the most common techniques used to fabricate continuous fiber reinforced composites. In composites consisting of several alternate layers of foils and fibers, some of the fibers form a triangular array, while others are arranged in a rectangular pattern directly one above another. A finite element analysis using the commercial code ABAQUS has been employed in order to determine which of these fiber arrays densifies at a slower rate, and hence controls the densification process. The simulation results, based on composites comprised of Ti-6A1-4V foils and SCS-6 silicon carbide fibers, showed that the triangular array densifies much faster than the rectangular. Foils comprising the rectangular array must undergo much higher strain than those comprising the triangular array in order to produce a fully densified composite. A slowing of the densification in both types of fiber arrays was observed in the latter stages of pore closure after two neighboring foils had estabished contact with each other. This slowing may be attributed to the required increase in strain as well as the low stress levels existing in the vicinity of the pore. The simulation results were used to describe the process by a closed form relationship, and to generalize our results so they may be applied to any composite system, since it includes the processing parameters, as well as fiber spacing (or fiber volume fraction), foil thickness and fiber diameter.Densification maps showing the change of density with time for a range of processing temperatures and applied stresses were also constructed. These maps may be used to select the consolidation parameters that will minimize the reaction zone formation at the matrix-reinforcement interface, the residual stresses and other adverse effects.     

Thermo-mechanical finite element analysis of a rail wheel

The rail wheel, which is acted upon by mechanical forces also experiences thermal stresses due to braking, during service. The coupled nature of these forces is analysed using a three-dimensional elasto-plastic finite element model. Contact stresses at the rail–wheel interaction location are analysed using a global–local approach on a three-dimensional elasto-plastic finite element model. The paper also brings out the size and shape of the plastic zone at the contact region. Commercial finite element code ABAQUS has been used for the analysis and SDRC’s I-DEAS has been used for modelling. American Association of Railroad’s standards, available for the purpose of analytical evaluation of the rail wheel, has also been critically evaluated in this work.     

轮毂结构有限元分析

随着数字化油田的全面展开,作为机械产品设计工作的数字化工作也随之展开。以轮毂为出发点,首先应用大型软件Pro／ENGINEER对轮毂进行三维建模,然后应用分析软件Pm／MECHANICA对轮毂的结构失效从结构静力学、动力学及疲劳分析三个方面进行了深入的研究。通过分析发现,虽然轮毂的静强度能满足设计要求,但其动力学响应的最大应力值已很接近轮毂材料的屈服强度,同时,通过疲劳分析,在该工况条件下,轮毂已经达不到相应的设计要求。     

轮式装载机湿式驱动桥结构有限元分析

轮式装载机的湿式驱动桥结构是由多个零、部件装配起来的复杂结构,由于该结构造型复杂并存在零、部件间的接触非线性、螺栓预紧力施加以及轴承合理简化等问题,其结构有限元分析具有较大难度。经反复研究实验,利用商用软件ANSYS成功地对该结构进行了详尽的有限元分析计算,获得了该结构的变形及应力分布,据此可以对车桥进行强度校核、结构改进,并为车桥结构的优化设计提供了重要依据。     

排油泵体的有限元分析

直线共轭内啮合齿轮泵是一种新颖的液压动力元件,靠外齿轮与内齿轮作内啮合运动进行工作。本文通过三维CAD软件建立齿轮泵的实体模型,利用Solidworks Simulation有限元分析软件,对实体的主要运动部件如排油泵进行分析,计算出排油泵体的应力、位移、应变及安全系数的变化范围,得出最大和最小值,通过分析结果对所设计的零件进行校核,计算出零件运作时的安全范围。