EFFECT OF HYGROTHERMAL LOADING ON LAMINATED FRP PLATES

Abstract

The use of fiber reinforced plastic (FRP) composite laminated plates is rapidly increasing all over the world due to its superior performance over conventional metal structures. But FRP composite material is subjected to stresses due to variation of temperature and moisture in various exposure conditions other than those due to mechanical loadings. The action of this variation of temperature and moisture is known as Hygrothermal loading. The laminated FRP composite is also relatively weak in shear compared to extensional rigidity. The Hygrothermal loading may further reduce the shear resistance of these laminated structures and may result delaminations. The aim of the present study is numerical modeling of Hygrothermal stresses of the FRP composite laminated plates. Thermal stress analysis of FRP composite laminated plates subjected to uniform temperature throughout the plate and linear thermal gradient across the thickness of the plate is done. This is presented in a simple and computationally efficient finite element analysis using general purpose Finite element software, ANSYS. Three finite element models for the analysis of thermal stress problems of FRP are presented and validated by comparing the obtained results with the existing literature. Studies have clearly shown the importance of appropriate finite element mesh for reliable prediction of thermal stresses and vertical deflection. A good number of cases are studied with varying parameters like stacking sequence, thickness ratio, aspect ratio, ply orientation. The parametric study is done both in case of uniform temperature through out the plate and in case of linear thermal gradient across the thickness of the plate and the effects are observed on thermal stresses and vertical deflection. Effect of skew angle in a FRP composite laminated skew plate subjected to linear thermal gradient across the thickness of the plate is also highlighted.