STABILITY ANALYSIS OF MULTi~CELLU'LAR FRP PANELS

Abstract

Over the past decade, FRP is gaining popularity in civil engineering and infrastructure building applications due to their inherent capabilities of possessing high specific strength and stiffness. Further, the capability to tailor these products into the required shape and size by varying their fiber orientations, number of layers etc. have enhanced the usage of such materials in our day to day requirement. Though FRP, being a high strength material, the thickness required to satisfy the strength constraint is very less resulting in a thin walled structure where the design is governed by stability requirements. Since very few studies have been carried out in this field, it is imperative to understand and study the stability characteristics of multi cellular FRP panels when subjected to varying parameters like fiber orientation, number of cells, boundary conditions and loading conditions. This buckling study will not only help us to understand the performance of these thin walled structures but shall also help in creating a data base for further analysis and research on the subject. In this thesis, numerical studies have been carried out to understand the buckling characteristics of graphite epoxy composite multi cellular box sections when subjected to in-plane and out of plane loading conditions where the panels have been subjected to IRC Class AA tracked loading. The results presented have been determined through the use ANSYS.10 software analysis. The effect of variation in fiber orientation and increase in number of cells on buckling response has been examined in some detail. It is shown that variation in fiber orientation and increase in number of cells can substantially improve the buckling capability of the box sections. The buckling mode shape is shown to depend significantly on the fiber orientation. The relative ease with which the ANSYS modeling method can accommodate changes in material properties and structural geometry permits the close examination of a wide range of the design variables and thus more efficient structural components can be realised. Optimised fiber orientation with regard to buckling of the composite box sections are indicated in the project for increase in number of cells and constant dimensions of the box as well as loading.