Nonlinear Constitutive Model for Anisotropic Biobased Composite Materials: Fid-Bau Portal

Nonlinear Constitutive Model for Anisotropic Biobased Composite Materials

Michel, A. T. / Billington, S. L.

Abstract

Biobased composites have been widely proposed in the literature as suitable replacements for a variety of engineered materials, with applications ranging from biomedical devices to automotive components to construction materials. Previous research has primarily focused on engineering biobased alternatives with mechanical and physical properties that either duplicate or exceed those of their synthetic counterparts. Although several elastic biobased composite design techniques have been proposed, modeling the complete material constitutive response, including the significant anisotropy and nonlinearity exhibited by many biobased composites, has not yet been explored. In this research, a transversely isotropic nonlinear constitutive model is modified and implemented in a finite-element framework to predict the mechanical response of natural woven fabric biopolymeric composites. A novel method for indirect calibration of constitutive model parameters from simple tension and flexure tests is proposed using a fiber section analysis and nonlinear optimization. Numerical predictions of anisotropic elastic and nonlinear hardening behavior are demonstrated in a comparison between experimental and finite-element analysis results for oriented hemp fabric–reinforced poly(3-hydroxybutyrate)-co-poly(3-hydroxyvalerate) (PHBV) polymer composites tested in flexure. Model results for 0, 45, and 90° and ${[\pm 30 / \pm 60 / 0]}_{s}$ oriented laminates tested in uniaxial tension and three-point bending closely matched the results of experiments. This modeling technique is proposed within the context of developing effective design tools that facilitate the adoption of engineered biobased composites into practice.