Perforated composite laminates are frequently encountered in multiple engineering applications as sub-components of complicated structures. In many of these applications, the primary objective of using the panel is to resist buckling under diverse environmental and loading conditions. This paper is mainly focused on the vibration and buckling responses of composite laminates with elliptical cutouts subjected to localized edge loads under different hygrothermal environments. Toward this, a nine-noded heterosis plate element has been utilized to discretize the plate by adopting a refined meshing pattern around the elliptical cutout. The geometric nonlinearity has been incorporated to predict free vibrations under the hygrothermal environment. Considering the plethora of applications of composite laminates in hygrothermal conditions, a new temperature/moisture-dependent model is presented by taking into consideration various mechanical loadings. For a given environmental and loading condition, the stress distribution within the perforated panel is highly non-uniform in nature and hence, a novel dynamic approach has been proposed to solve buckling problems by adopting two sets of boundary conditions. A MATLAB program has been developed to investigate the effect of various parameters such as elliptical cutout size, elliptical orientation, elliptical cutout eccentricity, thickness and boundary conditions of the laminated composite plate under diverse hygrothermomechanical loading conditions. A notable difference in the critical buckling load is observed when the locally prestressed perforated panels are subjected to complex hygrothermal environments, especially at larger elliptical cutouts and hence the importance of localized edge loads under hygrothermal environment is emphasized.

中文翻译：

---

局部边缘载荷下椭圆切口复合层压板的湿热机械振动和屈曲分析

穿孔复合层压板作为复杂结构的子组件在多种工程应用中经常遇到。在许多这些应用中，使用面板的主要目的是在不同的环境和负载条件下抵抗屈曲。本文主要关注具有椭圆切口的复合材料层压板在不同湿热环境下受到局部边缘载荷的振动和屈曲响应。为此，通过在椭圆切口周围采用精细的网格模式，利用九节点杂种优势板单元对板进行离散化。几何非线性已被纳入预测湿热环境下的自由振动。考虑到复合层压板在湿热条件下的大量应用，通过考虑各种机械载荷，提出了一种新的温度/湿度相关模型。对于给定的环境和载荷条件，穿孔板内的应力分布本质上是高度不均匀的，因此，提出了一种新的动态方法，通过采用两组边界条件来解决屈曲问题。已经开发了一个MATLAB程序来研究各种参数的影响，例如椭圆切口尺寸、椭圆方向、椭圆切口偏心率、厚度和层压复合板的边界条件在不同的湿热机械载荷条件下。当局部预应力穿孔板经受复杂的湿热环境时，观察到临界屈曲载荷的显着差异，