Stiffness Behaviour of GFRP Laminates: A Comparative Study of Analytical and Experimental Methods

Abstract

The study provides a critical comparison of micromechanically based methods, Classical Laminate Theory (CLT), and experimental validation for the prediction of mechanical properties of composite laminates. A symmetric and balanced ±37° glass fiber-reinforced polymer (GFRP) laminate was manufactured via the vacuum infusion technique, and its mechanical performance was evaluated by flexural tests and measurements of fiber volume fraction. Micromechanical models were used to calculate the properties of UD laminas, which have been incorporated within CLT to predict engineering constants at the laminate level. Parametric studies were carried out to explore the effect of the fiber orientation and Vf on the associated E_x, E_y, and G_xy. The results of the theoretical predictions have been found to be in good agreement with the experimental observations, with some discrepancies less than 3% for both longitudinal and transverse elastic moduli. The results indicated a highly anisotropic response that was controlled by fiber orientation, and an increase in fiber volume fraction increased stiffness in all directions markedly. The present work validates the accuracy of analytical modelling based on CLT for FRP laminates and develops critical understanding in terms of interaction between material components, fibre directionality and laminate mechanical behavior.