有限元的因次分析法

利用因次分析法对用有限元法所分析的结构进行分析,求得了模型和原型之间相似准则,对于同种材料的结构,当结构几何比为λl,外加动载荷之比为λl^2,振动频率之比为时1／λl,结构满足相似准则,则结构的振动加速度之比为1／λl,辐射声功率之比为λl^2。     

相似理论在大型复杂构件有限元分析中的应用

为克服一般有限元软件在分析大型复杂工程构件中的局限性,在有限元分析流程中引入相似理论,通过两者的结合可以有效地解决大型构件有限元分析中单元数量大、节点多和求解困难等缺点。以龙门起重机为例说明相似理论在有限元分析中的应用,分析表明相似理论在大型机械工程有限元分析中有重要的应用价值。     

有限元分析法在接触现象中的应用研究

主要研究了有限元方法在接触现象分析中的应用，提出了用有限元分析方法对接触问题进行求解的一般方法。同时给出了一个用大型有限元分析软件Marc来进行接触分析的实例。     

有限元在压机结构分析中的应用

根据压机结构的工作特点,应用有限元分析技术,对压机结构的强度、刚度进行分析计算,提高了压机设计质量和安全性.     

有限元分析法及其软件在齿轮接触强度分析中的应用

有限元分析法由于其快速、准确可靠、灵活的分析计算,因而在国内、外广泛采用.有限元分析软件有很多,其中ANSYS软件是一大型通用有限元分析软件.它能够计算在约束和载荷作用下离散化模型的应力和变形,并得出应力应变图和模拟动画.     

有限元分析法在挖掘机工作装置分析中的应用

将有限元分析法应用在液压挖掘机的工作装置中。分析了挖掘过程中承受的交变复合外力,以及工作装置的强度和变形情况;从而更好地了解动臂和斗杆是否坚固可靠,用以指导结构改型,使其设计更加合理。     

冲击破碎机冲击时间的因次分析及数值仿真研究

采用因次分析技术与数值仿真技术相结合的方法，对冲击式破碎机锤头与物料之间的冲击时间进行了研究。研究分两种情况进行，即锤头质量为有限值和锤头质量无穷大，分别得到了两种情况下的冲击时间计算式。结果表明：当锤头质量为无穷大时，冲击时间是无因次量可v^2ρ／E的函数；当锤头质量为有限值时，冲击时间为3个无因次量E2R2^3／（m1v1^2）、ρ2R2^3／m1、E1R2^3／（m1v1^2）的函数。     

利用有限元分析法预测楔横轧件心部缺陷

利用有限元分析预测楔横轧件的心部缺陷，预测时使用了两种积分塑性断裂准则。通过分析圆柱试样在拉伸试验时环形缺口的变化形状得到临界破坏值。试验研究了楔横轧模具的初始压缩量和模具轧制工件成形质量的关系。比较了理论分析与试验结果验证了破坏准则的有效性。最后，叙述了最佳成形工艺条件。     

有限元分析技术在注塑机拉杆结构分析中的应用

拉杆是注塑机提供合模力的重要构件。这里用有限元法对拉杆进行了有限元分析，并对拉杆的关键部位进行了材料力学测试，表明拉杆螺纹处的应力集中现象比较明显，并在此部位容易形成裂纹。测试和计算结果可为注塑机拉杆结构的改进设计提供参考。     

平衡条件在机械结构静态有限元分析中的应用

简要介绍了有限元分析及建立刚度矩阵的直接法,指出平衡条件是构成刚度矩阵和矩阵方程的基本条件,并通过实例说明在结构静态分析中应用平衡条件可以验证结论的精确性、求解未知载荷及消除无约束的结构静态分析中的奇异矩阵。     

Proximal-point method for finite element model updating problem

The problem of finding the optimal approximation to analytical stiffness matrix modeled by the finite element method is considered in this paper. Desired matrix properties, including satisfaction of the dynamic equation, symmetry, positive semidefiniteness and physical connectivity, are imposed as side constraints of the minimization problem. To the best of the author's knowledge, the finite element model updating problem containing all these constraints simultaneously has not been proposed in the literature earlier. By partial Lagrangian multipliers technique, the optimization problem is transformed into a matrix linear variational inequality and the proximal-point method is first used to solve the equivalent problem. The results of numerical examples show that the proposed method works well even for incomplete measured data.     

Polyhedral smoothed finite element method for thermoelastic analysis

Thermoelastic analysis by means of three-dimensional polyhedral elements based on the Smoothed Finite elements method (S-FEM), for example nodal Cell-based S-FEM (CS-FEM), Node-based S-FEM (NS-FEM), and Edge-based S-FEM (ES-FEM), was studied. S-FEM allows implicit shape functions, making it possible to construct shape functions of S-FEM based polyhedral elements in a straightforward manner. The performance of S-FEM based polyhedral elements was compared with one another and with the conventional finite elements including hexahedral and tetrahedral element. Numerical examples show that the polyhedral elements by means of CS-FEM and ES-FEM provide better accuracy and convergence rate than conventional hexahedral finite elements, while the polyhedral elements by means of NS-FEM leads to spurious mode.

     

Performance of the p-version finite element method for limit analysis

In this paper, we investigate the use of the p-version finite element method in carrying out limit analysis using a mathematical programming-based static approach. An important motivation for this study is to overcome the well-known locking behavior—caused by the incompressibility constraint—that may occur in plane strain and 3D problems for such common yield criteria as von Mises’. Quadrilateral elements and plane stress or plane strain structures are specifically considered. Various examples are provided to highlight the robustness and accuracy of the approach.     

A new method for finite element model updating in structural dynamics

A method is propounded in this paper to update finite element models in the field of structural dynamics. It is especially intended to solve cases for which other methods either cannot be applied or are inefficient. It is posed as the minimization of an error function defined in the time domain. The minimization is carried out by a novel adaptive sampling algorithm, which constitutes the main contribution in this work. In this algorithm, the solution is searched by sampling the parameters to be updated within a bounded space in an iterative form. The Beta distribution, which is consistent with the bounded character of the search space, is chosen for the sampling. The characteristics of the distributions are changed in each step of the process depending on the results of the previous ones. The method has been tested through a simulated dynamic model and an experimental case. In these particular cases, the performance of the proposed adaptive algorithm was better than those of other related stochastic algorithms it was compared with.     

Kineto-elastodynamic analysis of mechanisms by finite element method

In the present paper a systematic finite element method for kineto-elastodynamic analysis of high speed mechanisms has been presented. Effects of number of divisions have been investigated and it is found that a certain minimum number of divisions of links is necessary to yield accurate results. A new approach for eliminating the singularity in the stiffness matrices of mechanisms has been developed and it has been shown in this paper that this new approach yields improved results with negligible additional effort. Finite element expressions for the coriolis, tangential and normal components of elastic accelerations have been derived for a moving link and a new geometric stiffness matrix has been developed to include the effects of the rigid body pinforces and the distributed axial rigid body inertia forces on the transverse vibrations of the links. The method has been further extended to take into account the nonlinear elastic axial forces. Several examples have been solved.     

Nodeless variable finite element method for stress analysis using flux-based formulation

A nodeless variable element is combined with an adaptive meshing technique to improve solution accuracy of the finite element method for analyzing two-dimensional elasticity problems. The nodeless variable element employs quadratic interpolation functions to provide higher solution accuracy without requiring additional actual nodes. The fluxbased formulation is developed for the nodeless variable finite element to reduce the complexity in deriving the finite element equations as compared to the conventional finite element method. The superconvergent patch recovery procedure is implemented to compute accurate stresses from the nodeless variable finite element solutions. The effectiveness of the combined procedure for providing higher solution convergence rate from the proposed formulation is evaluated by two well-known examples.     

Acoustic analysis of lightweight auto-body based on finite element method and boundary element method

A lightweight automotive prototype using alternative materials and gauge thickness is studied by a numerical method. The noise, vibration, and harshness (NVH) performance is the main target of this study. In the range of 1–150 Hz, the frequency response function (FRF) of the body structure is calculated by a finite element method (FEM) to get the dynamic behavior of the auto-body structure. The pressure response of the interior acoustic domain is solved by a boundary element method (BEM). To find the most contributing panel to the inner sound pressure, the panel acoustic contribution analysis (PACA) is performed. Finally, the most contributing panel is located and the resulting structural optimization is found to be more efficient. __________ Translated from Journal of Shanghai Jiaotong University, 2006, 40(1): 177–180 [译自: 上海交通大学学报]     

箔式应变片结构模型与有限元分析

长期以来，人们一直关心应变片的应变传递机理，以及应变片各组成部分对其性能的影响。Larry Burrow用有限元方法对应变片结构模型进行了分析，并分析了应变片系统中各组成元件对其性能的影响。     

隔离体法在有限元接触分析中的应用

这里针对施加初始预紧力时超高压密封容器有限元整体接触计算不收敛的情况,给出一种近似的计算思路—隔离体法。运用此方法,建立了该容器密封接触计算的等效隔离体模型,并运用有限元软件对该模型进行了计算,同时利用密封线比压判断准则对计算结果进行等效判断。经工程试验验证,计算结果合理,表明该近似方法的有效性。