Prediction of Orthotropic Hygroscopic Swelling of Fiber-Reinforced Composites from Isotropic Swelling of Matrix Polymer

Abstract

Swelling in fiber-reinforced composites is anisotropic. In this work, dealing with glass fiber epoxy composite immersed in distilled water, swelling coefficients are obtained in each direction experimentally. Swelling behaviour in the fiber direction was constrained by the non-swelling fibers and was close to null, while swelling in the transverse directions was found to occur freely—similar to the unconstrained polymer. An analytical method for predicting anisotropic swelling in composites from the swelling of the matrix polymer is reported in this work. The method has an advantage that it is simple to use in practice and requires only a swelling coefficient of the matrix polymer, elastic constants of the matrix and fibers, and a known fiber volume fraction of the composite. The method was validated using finite element analysis. Good agreement was obtained and is reported between experimental hygroscopic swelling data, analytical and numerical results for composite laminates, indicating the validity of this predictive approach.

Hygrothermal chamber aging effect on mechanical behavior and morphology of glass fiber-epoxy-nanoclay composites

“…From figures 5 (b), (d) and (f) and table 5, it can be observed that artificial aging has declined the tensile strength and modulus of GFENCs compared to unaged specimens. Absorbed moisture in the matrix induces swelling and de-bonding of the fiber-matrix [35]. Under artificial aging, molecules of water infiltrate into the micro-voids in GFENCs, leads to crack propagation.…”

Modelling of Environmental Ageing of Polymers and Polymer Composites—Modular and Multiscale Methods

“…The swelling strain increases linearly with increasing water concentration for both composites and polymers [ 93 , 96 ]. For orthotropic laminates, three CHEs; are needed to predict swelling [ 112 ].…”

“…Krauklis et al (2019) have shown that the hygroscopic swelling of FRPs can be analytically predicted from the swelling of the polymer using a model based on linear elasticity [ 112 ]. The model correlated well with experimental results and was validated by comparison with a Finite Element (FE) analysis.…”

Modular Paradigm for Composites: Modeling Hydrothermal Degradation of Glass Fibers

“…A composite's fiber fractions can be determined via density measurements [2,32,34,36] or burnoff tests following the ASTM Standard D3171 [58]. The volumetric and mass fiber fractions can be calculated using the following Equations ( 15) and ( 16), respectively:…”