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Present Element (present + element)
Selected AbstractsEight-node shell element based on incompatible modesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 2 2009Desheng Xu Abstract This paper concerns the shell element formulation used for linear analysis. Introduction of hierarchical incompatible modes into the ordinary 8-node solid element is very effective to obtain the rational deflection,rotation relationship. An efficient revision scheme without using numerical volume integration is developed to ensure the satisfaction of the patch test. A lot of numerical tests are carried out for the validation of the present element. Numerical results show that the element can give satisfactory accuracy and convergence, especially for moderately thick shells. Copyright © 2008 John Wiley & Sons, Ltd. [source] A new 3-node triangular flat shell elementINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 3 2002J. G. Kim Abstract The purpose of this work is to propose a new 3-node triangular flat shell element with 18 degrees of freedom. The element is constructed by superimposing the local membrane formulation due to Bergan and Felippa with the well-known DKT bending formulation due to Batoz. The numerical performance of the present element has been compared with several reported 18 degrees-of-freedom triangular shell elements in a number of benchmark test problems. Copyright © 2002 John Wiley & Sons, Ltd. [source] Optimal solid shell element for large deformable composite structures with piezoelectric layers and active vibration controlINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 15 2005X. G. Tan Abstract In this paper, we present an optimal low-order accurate piezoelectric solid-shell element formulation to model active composite shell structures that can undergo large deformation and large overall motion. This element has only displacement and electric degrees of freedom (dofs), with no rotational dofs, and an optimal number of enhancing assumed strain (EAS) parameters to pass the patch tests (both membrane and out-of-plane bending). The combination of the present optimal piezoelectric solid-shell element and the optimal solid-shell element previously developed allows for efficient and accurate analyses of large deformable composite multilayer shell structures with piezoelectric layers. To make the 3-D analysis of active composite shells containing discrete piezoelectric sensors and actuators even more efficient, the composite solid-shell element is further developed here. Based on the mixed Fraeijs de Veubeke,Hu,Washizu (FHW) variational principle, the in-plane and out-of-plane bending behaviours are improved via a new and efficient enhancement of the strain tensor. Shear-locking and curvature thickness locking are resolved effectively by using the assumed natural strain (ANS) method. We also present an optimal-control design for vibration suppression of a large deformable structure based on the general finite element approach. The linear-quadratic regulator control scheme with output feedback is used as a control law on the basis of the state space model of the system. Numerical examples involving static analyses and dynamic analyses of active shell structures having a large range of element aspect ratios are presented. Active vibration control of a composite multilayer shell with distributed piezoelectric sensors and actuators is performed to test the present element and the control design procedure. Copyright © 2005 John Wiley & Sons, Ltd. [source] Buckling analysis for delaminated composites using plate bending elements based on higher-order zig-zag theoryINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 11 2002Jun-Sik Kim Abstract A finite element based on the efficient higher-order zig-zag theory with multiple delaminations is developed. The bending part of the formulation is constructed from the concept of DKQ element. Unlike conventional elements, a developed element has its reference in the bottom surface which simplifies zig-zag terms on formulation. Exact patch solutions are developed on elements which have the bottom reference system. The present element passes proper bending patch tests in the arbitrary mesh configurations in isotropic materials. Zig-zag formulation is adopted to model laminated plates with multiple delaminations. To assess the accuracy and efficiency of the present element based on higher-order zig-zag theory with multiple delaminations, the linear buckling problem of laminated plates with multiple delaminations has been analysed. The results have been compared with three-dimensional elasticity solutions. The present element works as an efficient tool for analysing the behaviour of the laminated composites with multiple delaminations. Copyright © 2002 John Wiley & Sons, Ltd. [source] Thesis as Narrative or ,What Is the Inquiry in Narrative Inquiry?'CURRICULUM INQUIRY, Issue 2 2000Carola Conle I present elements of inquiry in a dissertation composed through experiential narrative. My account of the thesis process is interwoven with references to John Dewey's demonstrations of implicit inquiry in the creation and experience of art. Motivation, methodology, outcomes and literature review take on a narrative character and I show how aesthetic and reflective activities contributed to the inquiry. Conceptually, a ,tension-telos dynamic' characterizes the impetus for the work; ,resonance' is portrayed as the connecting principle among various narrative components of the thesis, and the function of a ,third term' in metaphorical relationships is presented as a structuring principle for these connections. Although my inquiry came about through personal stories, my narratives reached out to social, historical and philosophical contexts to gain a wider significance, academically and personally. [source] Learning Spaces: an ICT-enabled model of future learning in the Knowledge-based SocietyEUROPEAN JOURNAL OF EDUCATION, Issue 2 2007YVES PUNIE This article presents elements of a future vision of learning in the knowledge-based society which is enabled by ICT. It is not only based on extrapolations from trends and drivers that are shaping learning in Europe but also consists of a holistic attempt to envisage and anticipate future learning needs and requirements in the KBS. The ,learning spaces' vision puts learners at the centre of learning, but, at the same time, conceives learning as a social process. The potential of ICT-enabled learning spaces can only be realised, however, if it is embedded in a social and institutional context that is open to innovation and supported by a favourable policy environment. [source] | |||||||||||||