含损伤复合材料AGS板的屈曲特性

BUCKLING BEHAVIOR OF COMPOSITE AGS WITH DELAMINATION

采用有限元数值模拟方法,研究了蒙皮内含分层损伤复合材料格栅加筋板结构(AGS)的稳定性问题。对蒙皮和肋骨分别采用基于Mindlin一阶剪切理论的复合材料层合板单元和层合梁单元来模拟,推导了相应的有限元列式,并通过坐标变换,利用蒙皮与肋骨的几何连续条件,形成了AGS的单元刚度阵和几何刚度阵,建立了含损伤AGS稳定性分析的有限元控制方程。通过典型算例,研究了压缩载荷作用下,分层形状、分层大小、分层深度、肋骨的高度和宽度、布置方式等因素对AGS的稳定性特征的影响。数值结果表明,含分层损伤的AGS具有十分复杂的屈曲性态。屈曲临界力和屈曲模式与分层面积、分层形状、分层深度、肋骨的高度和宽度、布置方式和位置均密切相关。

A finite element method was developed for tbe numerical analysis of advanced grid stiffened structure （AGS）, and tbe stability problem of AGS with an embedded delamination was investigated. Based on the Mindlin first-order shear deformation theory, a composite laminates element and a beam element were adopted to model the skin and the stiffener, respectively, The corresponding formulae for finite element analysis were deduced. Bycoordinate transformation and the geometry continuom condition of tbe skin and the stiffener, the element stiffness matrices and geometrical stiffness matrices for the AGS were deduced. The governing equation for the stability problem of the composite grid stiffened plate and shell was established. The effects of configuration, size, and location of the delamination, and the height, the width, the distribution of the stiffeners on the stability cbaracteristics of the AGS subjected to a compressive load are discussed. The numerical investigation indicates that the buckling behavior of the AGS is much more complicated, The buckling load and modes relate to the configuration, size, and location of the delamination, and the heigbt, the width, the distribution of the stiffeners closely.