Optimization of Tensile Strength in Glass Fiber-Reinforced Composites using Regular and Bio-Based Epoxy using Taguchi Approach

Abstract

The tensile strength of glass fiber-reinforced composites, using both regular and bio-based epoxy resins, was investigated through a series of tensile tests. The study analyzed composites with 30° and 45° fiber orientations and varying numbers of fiber layers (1 to 4). For regular epoxy at a 30° orientation, tensile strength improved by 41%, 65%, 92%, and 120% as the layer count increased. Bio-based epoxy composites outperformed these, showing tensile strength increases of 51%, 88%, 122%, and 159%. Similar trends were observed for 45° fiber orientation, where regular epoxy improved by 56%, 83%, 114%, and 147%, and bio-based epoxy composites improved by 67%, 110%, 153%, and 189%. While bio-based epoxy exhibited superior percentage improvements, its absolute tensile strength remained lower due to its flexible polymer network compared to the rigid structure of regular epoxy. This disparity is linked to differences in polymer architecture, with regular epoxy's tightly cross-linked chains providing higher rigidity. Additionally, the 45° fiber orientation consistently resulted in higher tensile strength improvements, attributed to better stress distribution and resistance to shear forces. Taguchi optimization was employed, using an L16 orthogonal array to systematically explore the effects of fiber orientation (30°, 35°, 40°, 45°) and the number of layers (1-4). The "larger is better" signal-to-noise (S/N) ratio was applied, with the optimal configuration identified as 45° fiber orientation with 4 layers, offering the most substantial tensile strength improvement, aligning with established materials science findings.