The p-version of finite element method for shell analysis

A new quadrature scheme and a family of hierarchical assumed strain elements have been developed to enhance the performance of the displacement-based hierarchical shell elements. Various linear iterative procedures have been examined for their suitability to solve system of equations resulting from hierarchic shell formulations.     

企业质量管理体系结构模型设计

在分析企业质量管理体系结构三种主要表述方法及其存在问题的基础上，运用系统工程原理及ISO9000族标准和TQM的基本原理建立了质量管理体系三维空间结构模型，并以产品实现过程维中的“生产和服务运作”为特例，探讨了产品实现过程维、过程策划维和质量改进维三维之间的网络关系。这一空间结构模型可用于评价企业质量管理体系的有效性，并为进一步研究质量管理体系的经济性奠定了基础。     

未来厨房系统的情感交互设计研究

目的研究信息时代未来厨房系统中用户与厨房间的人机交互和情感交互。方法分析未来厨房系统的内涵、组成元素和设计原则,总结人机交互及人际交互中情感的交流方式。结果绿色商业厨房与家庭成长模块化厨房设计实例进行的情感交互设计能使未来厨房系统的操作变得更加人性化,为人们的生活创造更好的体验价值和人机、人际情感交互,构建和谐稳定的家庭关系。     

A GENERAL FORMULATION OF EQUILIBRIUM MACRO-ELEMENTS WITH CONTROL OF SPURIOUS KINEMATIC MODES: THE EXORCISM OF AN OLD CURSE

This paper illustrates a method whereby a family of robust equilibrium elements can be formulated in a general manner. The effects of spurious kinematic modes, present to some extent in all primitive equilibrium elements, are eliminated by judicious assembly into macro-equilibrium elements. These macroelements are formulated with sufficient generality so as to retain the polynomial degree of the stress field as a variable. Such a family of macro-elements is a new development, and results for polynomials of degree greater than two have not been seen before. The quality of results for macro-equilibrium elements with varying degrees of polynomial is demonstrated by numerical examples.     

Anisotropic mixed finite elements for elasticity

In this paper, we present a family of mixed finite elements, which are suitable for the discretization of slim domains. The displacement space is chosen as Nédélec's space of tangential continuous elements, whereas the stress is approximated by normal–normal continuous symmetric tensor‐valued finite elements. We show stability of the system on a slim domain discretized by a tensor product mesh, where the constant of stability does not depend on the aspect ratio of the discretization. We give interpolation operators for the finite element spaces, and thereby obtain optimal order a priori error estimates for the approximate solution. All estimates are independent of the aspect ratio of the finite elements. Copyright © 2011 John Wiley & Sons, Ltd.     

Triangular finite elements for the generalized Bessel equation of order m

A new family of triangular finite elements is described, useful for solving the axisymmetric vector Helmholtz equation, and a variety of scalar Helmholtz equation problems which lead to generalized Bessel equations of some order m. This family is similar in principle to the scalar axisymmetric Helmholtz elements derived earlier, but requires both reformulation of its describing equations and corresponding new universal element matrices, for successful computational implementation. The necessary formulation is given in this paper. Matrix elements to the sixth-order inclusive have been calculated and extensively tested computationally.     

A comparison between isoparametric Lagrangian elements in 2D BEM

A comparison between a family of isoparametric C°-continucus elements in the context of two-dimensional elastostatics using the direct boundary element method is presented. The elements studied use Lagrangian shape functions of orders quadratic, cubic and quartic. The relative efficiencies of these elements from the viewpoint of accuracy of solution as well as cost effectiveness are examined through certain selected problems. It emerges from the present study that the quartic element is more reliable in accuracy than the lower members of the family without being necessarily more expensive.     

Product family formation and selection for reconfigurability using analytical network process

The paper develops a conceptual framework for product family formation towards reconfigurability through proposing a product-process reconfiguration link. Different decisive factors affecting product family formation and selection such as manufacturing requirements, market requirements, manufacturing cost and process reconfiguration are investigated. An analytical network process (ANP) model is proposed to incorporate all the outlined decisive factors and major criteria and elements influencing the product family formation and selection. As a consequence of the interactive nature of the product family selection problem, most of the children's’ elements within the same cluster and/ or different clusters are associated with each other. As a result, all the clusters are connected to each other (outer dependencies) as well as their connections to themselves (inner dependencies). The proposed ANP model is examined through a case study in a manufacturing company for validation. Synthesis judgments and sensitivity analysis are carried out for selecting the most appropriate product family along with analysing the influence of the selected critical elements.     

A quintic conforming plate bending triangle

A new family of conforming triangular plate bending elements, based on the Displacement Method of formulation, is developed in detail in Reference 9. The elements can be of any order n?4, and do not present excess nodal continuties at the corner nodes. For a given element, the assumed vertical displacement w consists of a polynomial expansion supplemented by three rational function. Polynomial completeness is of order n for even n, and of order n-1 for odd values of n. This family is proposed as a desirable alternative to refined triangular elements which incorporate all three curvatures as corner node variables,⁸ or require constraint equations to enforce inter-element compatibility,¹⁰ The purpose of this paper is to describe the quintic member of the family. The traditional difficulties associated with the discontinuous curvatures of the rational functions are solved in a straightforward fashion. The element has the same good accuracy as the other, well-known, quintic triangle, ^3,4,8 and some additional advantages accruning from the simplicity of its nodal variables. A similar performance can be anticipated with the other members of the family.     

基于心流理论的家庭智能健身心流体验要素分析

目的 基于心流理论,提炼家庭智能健身场景下的心流体验要素及其需求层级表。方法 首先通过定性定量研究,分析家庭健身场景及用户行为,提炼家庭智能健身心流体验要素,同时提出假设;然后将其要素分点转译为心流体验量表语句,采用5级李克特量表形式对所有健身用户进行问卷调研;最后对问卷回收数据进行信效度检验、相关性分析与回归分析。结果:提炼了家庭智能健身心流体验要素,在前人总结的9个心流体验要素基础上,新增“造型符合审美”“时空自由”“持续的监督与鼓励”“情境属性”4个要素;构建心流体验结果要素回归方程,描述了家庭智能健身场景中心流体验前兆要素、过程要素,以及其他潜在因子与心流体验结果要素之间的相关关系,否定了男女健身心流体验的差异,验证了其他假设的合理性。最后基于用户体验视角提出了心流体验要素需求层级表。结论 家庭智能健身心流体验要素兼具合理性与普适性,心流体验要素需求层级表对未来的家庭智能健身产品设计具有一定的理论指导意义。     

Two-dimensional elastoplasticity: Approximation by mixed finite elements

Two-dimensional elastoplastic problems are used to assess the performance of a family of mixed finite elements in the non-linear regime. In particular, four-node bilinear quadrilateral elements that exhibit high accuracy in coarse meshes are used to simulate plane stress, plane strain, axisymmetric and (shear-deformable) plate bending problems. The excellent performance of these elements is demonstrated with a number of discriminating examples selected from the literature. In addition, agreement is observed in the limit load predicted by the axisymmetric solid and plate bending elements.     

A family of ANS four‐node exact geometry shell elements in general convected curvilinear coordinates

The non‐conventional exact geometry shell elements based on the Timoshenko–Mindlin kinematics with five displacement degrees of freedom are proposed. The term ‘exact geometry (EXG)’ reflects the fact that coefficients of the first and second fundamental forms of the reference surface and Christoffel symbols are taken exactly at every Gauss integration point. The choice of only displacements as fundamental shell unknowns gives an opportunity to derive strain–displacement relationships, which are invariant under rigid‐body shell motions in a convected curvilinear coordinate system. This paper presents a newly developed family consisting of three hybrid and one displacement‐based four‐node EXG shell elements. To avoid shear and membrane locking and have no spurious zero energy modes, the ANS concept is employed. The ANS interpolations satisfy exactly the plate compatibility equation for in‐plane strains. As a result, all EXG shell elements developed pass membrane and bending plate patch tests and exhibit a superior performance in the case of distorted coarse mesh configurations. Copyright © 2010 John Wiley & Sons, Ltd.     

A family of variable section curved beam and thick-shell or membrane-stiffening isoparametric elements

A family of isoparametric curved beam elements of a general, compact cross-section is introduced. The formulation is based on beam theory and takes into account both transverse shear deformation and shear centre location. The elements exhibit the required displacement compatbility with Ahmad's superparametric thick-shell elements and isoparametric membrane elements. Examples presented at the end of the paper illustrate the validity of the formulation and the possibility of practical application of the elements.     

Finite-rotation shell elements via mixed formulation

Starting from a tensorial five-parametric finite-rotation shell theory a family of mixed finite elements is developed on the basis of a Reissner-Mindlin type functional. The family developed contains 4-node and 9-node quadrilateral shell elements. In each of them the displacement approximation is combined with various force variable interpolations in order to improve flexibility for numerical applications. The so-called difference vector occurring in the shell theory is expressed in terms of new rotational degrees of freedom which permit a unique determination of this variable in every deformed position. The corresponding constraints are then satisfied at the element level numerically. Due to the underlying theory the numerical models developed are able to predict the physical 2D force variables accurately. Their capability to deal with strongly nonlinear situations is demonstrated by several examples where numerical results due to Kirchhoff-Love type elements are also included for a systematical comparison.     

A family of conforming finite elements for deep shell analysis

The problem related to the derivation of conforming deep shell finite elements is examined in the light of the thin shell theory and using the classical Loves strain energy formulation. A family of quadrangular finite elements allowing for variable curvature is developed. It is shown how an exact conformity of the displacements can be ensured in a large number of cases. Various static and dynamic applications are used to illustrate the advantages of these elements.     

Assuring Product Quality in the Production of Nanoelectronic Components

Nanoelectronics, the next great change in product technology, offers the potential to revolutionize the electronics industry, spawn new product families, and change the way products are designed and manufactured. To accomplish this, product quality must be kept at levels heretofore unattainable. Using a system dynamics approach, this article examines the available cadre of measurement and control techniques for applicability. Changes in the way that the tools are used and the results interpreted are required. It will also be necessary to develop a new family of instrumentation that will allow real-time feedback and almost instantaneous correction to process elements.     

A variable thickness,curved beam and shell stiffening element with shear deformations

A family of 2-D and 3-D superparametric curved beam elements are introduced as a special form of general 2-D and 3-D isoparametric continuum elements. Each beam ‘subelement’ is rectangular incross section, however several elements may be offset and overlayed for the analysis of structural members of quite general section properties. A number of examples are presented in order to illustrate the validity and range of application of the element.     

A C1 finite element family for Kirchhoff plate bending

After a short introduction the possibilities and limitations of polynomial simple elements with C¹ continuity are discussed with reference to plate bending analysis. A family of this kind of elements is presented. These elements are applied to simple cases in order to assess their computational efficiency. Finally some conclusions are shown, and future research is also proposed.     

On enhanced strain methods for small and finite deformations of solids

Numerical simulations of engineering problems require robust elements. For a broad range of applications these elements should perform well in bending dominated situations and also in cases of incompressibility. The element should be insensitive against mesh distortions which frequently occur due to modern mesh generation tools or during finite deformations. Possibly the elements should not lock in the thin limits and thus be applicable to shell problems. Furthermore due to efficiency reasons a good coarse mesh accuracy is required in nonlinear analysis. In this paper we discuss the family of enhanced strain elements in order to depict the positive and negative aspects related to these elements. Throughout this discussion we use numerical examples to underline the theoretical results.     

A goal-oriented dual-weighted adaptive finite element approach for the optimal control of a nonsmooth Cahn–Hilliard–Navier–Stokes system

This paper is concerned with the development and implementation of an adaptive solution algorithm for the optimal control of a time-discrete Cahn–Hilliard–Navier–Stokes system with variable densities. The free energy density associated with the Cahn–Hilliard system incorporates the double-obstacle potential which yields an optimal control problem for a family of coupled systems in each time instant of a variational inequality of fourth order and the Navier–Stokes equation. A dual-weighted residual approach for goal-oriented adaptive finite elements is presented which is based on the concept of C-stationarity. The overall error representation depends on primal residuals weighted by approximate dual quantities and vice versa as well as various complementarity mismatch errors. Details of the numerical realization of the adaptive concept and a report on the numerical tests are given.