...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Zeitschrift fur Angewandte Mathematik und Mechanik >A Generalized Nonlinear Finite Element Formulation for Composite Shells
【24h】

A Generalized Nonlinear Finite Element Formulation for Composite Shells

机译：复合材料壳体的广义非线性有限元公式

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In recent years the application of composite materials in structures has become increasingly popular. The large strength and stiffness ratios in a laminate demands new design requirements, such as estimation of interlaminar stresses along free edges, cutouts, rivet holes etc. which implies the accurate calculation of the stress field. This is in general not possible using a 'classical' or degenerated shell element with 5 or 6 degrees of freedom. These models do not account for continuity of the shear stress components acting on laminar interfaces and the normal stresses itself. Higher-order theories for multilayered plates/shells have been subject of much research since the early 1970_s, see e.g. the survey article of Noor, Burton and Peters ([2]). Cubic polynomials in thickness direction are used in third-order shear-deformation models to interpolate the displacements. However these models do not fulfill continuity of the stresses across the interfaces. In discrete-layer models the transverse variation of the displacement field is represented by piecewise linear functions (multi-director theory). Each layer is considered as a homogeneous shell with constant material properties. Numerical models for linear composite plate and shells have been considered among others in e.g. Reddy, Barbero and Teply ([5]). Geometrical nonlinear FE-formulations are presented in e.g. Reddy and Chandrashekhara ([4]), Wagner and Gruttmann ([6]). A multi-director-theory has been used in Gruttmann, Wagner, Meyer and Wriggers ([1]) to develop a layerwise composite shell element with improved through the thickness distribution of the transverse shear. The objective of this paper is to develop a geometrical nonlinear 2-D, displacement-based finite element model which is capable to predict the shear stresses and the normal stresses in thickness direction accurately. Thus we introduce a displacement field with piecewise polynomial functions through the thickness according to the theory of Reddy([3]), here applied to geometrically nonlinear shell-like structures. Within this formulation the theory accounts for all six strain components. Each layer has constant material properties thus may be treated as a homogeneous shell. Within a material formulation the kinematic of a shell is discussed. The shell consists of N numerical layers with thickness ~ih. The numerical layers are not necessarily identical with the n actual layers of thickness ~jh. Thus each actual layer can be subdivided into several sublayers or viceversa several layers can be summarized to an equivalent numerical layer. The position vector X_0 is labeled with convective coordinates (direct-)~α. An orthonormal basis system t_k((direct-)~α) is attached to this surface with t_3 as normal vector and (direct-)~3 the coordinate in thickness direction.
机译：近年来，复合材料在结构中的应用变得越来越流行。层压板中较大的强度和刚度比要求新的设计要求，例如，估算沿自由边缘，切口，铆钉孔的层间应力，这意味着必须精确计算应力场。通常，使用具有5或6个自由度的“经典”或退化的壳元素是不可能的。这些模型没有考虑作用在层流界面上的剪应力分量和法向应力本身的连续性。自1970年代初期以来，多层板/壳的高阶理论一直是许多研究的主题，例如参见Noor，Burton和Peters的调查文章（[2]）。在三阶剪切变形模型中使用厚度方向上的三次多项式对位移进行插值。但是，这些模型不能满足界面上应力的连续性。在离散层模型中，位移场的横向变化由分段线性函数（多指向理论）表示。每层都被视为具有恒定材料特性的均质壳。线性复合板和壳的数值模型已被考虑在内，例如。雷迪，巴贝罗和特普利（[5]）。几何非线性有限元公式在例如Reddy和Chandrashekhara（[4]），Wagner和Gruttmann（[6]）。在Gruttmann，Wagner，Meyer和Wriggers（[1]）中已经使用了一种多指导理论来开发一种层状复合壳单元，并通过横向剪切的厚度分布进行了改进。本文的目的是建立一个基于几何非线性二维位移的有限元模型，该模型能够准确预测厚度方向的切应力和法向应力。因此，根据Reddy（[3]）的理论，我们通过厚度引入了具有分段多项式函数的位移场，此处将其应用于几何非线性壳状结构。在这个公式中，理论考虑了所有六个应变分量。每一层具有恒定的材料特性，因此可以视为均质壳。在材料配方中，讨论了壳体的运动学。壳层由N个数字层组成，厚度为〜ih。数值层不必与厚度为〜jh的n个实际层相同。因此，每个实际层可以细分为几个子层，反之亦然，可以将几个层总结为等效的数值层。位置向量X_0用对流坐标（direct-）〜α标记。正交法系t_k（（direct-）〜α）以t_3为法向向量，（direct-）〜3为厚度方向的坐标附着到该表面。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号