Abstract

This study is motivated by the need to understand the effect of elliptical cutouts on the buckling and vibration characteristics of stiffened composite panels under the influence of various types of non-uniform in-plane edge loads. The study is carried out by using a Finite Element (FE) formulation wherein the plate, and the stiffener are discretized by employing a 9-noded heterosis plate element and a 3-noded isoparametric beam element, respectively. The contributions of shear deformation and rotary inertia are considered in the FE formulation. Since the stress distribution within the panel is highly non-uniform for a given loading and geometric imperfection, a dynamic approach has been adopted to solve the buckling problem wherein two sets of boundary conditions are used to calculate the pre-buckling stresses and the buckling load of the stiffened panel. A new structured mesh pattern is proposed to house the stiffeners attached to the centrally located elliptical cutout panel in the form of a grid so that the stiffener can be attached anywhere and in any direction as per the requirements. The influences of various parameters, such as ply orientation, cutout size, cutout orientation, boundary conditions and depth to width ratio of the stiffener, are examined in detail. From the analysis, it is noticed that the depth of the stiffener has a significant effect on the buckling and vibration characteristics of the panel.

摘要

这项研究的动机是需要了解在各种类型的非均匀面内边缘载荷的影响下，椭圆形切口对加筋复合材料板的屈曲和振动特性的影响。该研究是通过使用有限元 (FE) 公式进行的，其中板和加劲肋分别通过采用 9 节点异质板单元和 3 节点等参梁单元进行离散化。有限元公式中考虑了剪切变形和旋转惯性的贡献。由于对于给定的载荷和几何缺陷，面板内的应力分布高度不均匀，采用动态方法来解决屈曲问题，其中使用两组边界条件来计算加筋板的预屈曲应力和屈曲载荷。提出了一种新的结构化网格图案，以网格的形式容纳连接到位于中心的椭圆形切口面板的加强筋，以便加强筋可以根据要求以任何方向连接到任何地方。详细研究了各种参数的影响，例如铺层方向、切口尺寸、切口方向、边界条件和加强筋的深度与宽度比。从分析中可以看出，加劲肋的深度对面板的屈曲和振动特性有显着影响。提出了一种新的结构化网格图案，以网格的形式容纳连接到位于中心的椭圆形切口面板的加强筋，以便加强筋可以根据要求以任何方向连接到任何地方。详细研究了各种参数的影响，例如铺层方向、切口尺寸、切口方向、边界条件和加强筋的深度与宽度比。从分析中可以看出，加劲肋的深度对面板的屈曲和振动特性有显着影响。提出了一种新的结构化网格图案，以网格的形式容纳连接到位于中心的椭圆形切口面板的加强筋，以便加强筋可以根据要求以任何方向连接到任何地方。详细研究了各种参数的影响，例如铺层方向、切口尺寸、切口方向、边界条件和加强筋的深度与宽度比。从分析中可以看出，加劲肋的深度对面板的屈曲和振动特性有显着影响。详细检查了加强筋的边界条件和深度与宽度之比。从分析中可以看出，加劲肋的深度对面板的屈曲和振动特性有显着影响。详细检查了加强筋的边界条件和深度与宽度之比。从分析中可以看出，加劲肋的深度对面板的屈曲和振动特性有显着影响。