An orthotropic hyperfoam-based model for the compressive response of aged polyurethane foams
Journal
Engineering Research Express
ISSN
2631-8695
Publisher
IOP Publishing
Date Issued
2025-11-27
Type
text::journal::journal article
Abstract
<jats:title>Abstract</jats:title>
<jats:p>This study presents a constitutive modeling framework to characterize the uniaxial compressive response of polyurethane foams subjected to nine distinct accelerated aging conditions. A new orthotropic, three-term Hyperfoam-based model was simultaneously calibrated for two principal material directions using previously published experimental data. The unified model was successfully fitted to the experimental stress-strain curves, achieving coefficients of determination greater than 0.78 in all cases. This demonstrates its capability to capture the material’s characteristic response, even under severe degradation that significantly increases experimental variability. Analysis of energy absorption and efficiency revealed that while the model is accurate for mild to moderate degradation states, deviations are observed at high strains (above a compressive strain of 0.7) for severely degraded samples. Crucially, the analysis of the fitted orthotropic response quantitatively demonstrates that severe aging accentuates the foam’s mechanical anisotropy. This work establishes a quantitative link between aging conditions, the evolution of mechanical properties, and the orthotropic constitutive parameters, providing a predictive tool for evaluating the material’s directional performance.</jats:p>
<jats:p>This study presents a constitutive modeling framework to characterize the uniaxial compressive response of polyurethane foams subjected to nine distinct accelerated aging conditions. A new orthotropic, three-term Hyperfoam-based model was simultaneously calibrated for two principal material directions using previously published experimental data. The unified model was successfully fitted to the experimental stress-strain curves, achieving coefficients of determination greater than 0.78 in all cases. This demonstrates its capability to capture the material’s characteristic response, even under severe degradation that significantly increases experimental variability. Analysis of energy absorption and efficiency revealed that while the model is accurate for mild to moderate degradation states, deviations are observed at high strains (above a compressive strain of 0.7) for severely degraded samples. Crucially, the analysis of the fitted orthotropic response quantitatively demonstrates that severe aging accentuates the foam’s mechanical anisotropy. This work establishes a quantitative link between aging conditions, the evolution of mechanical properties, and the orthotropic constitutive parameters, providing a predictive tool for evaluating the material’s directional performance.</jats:p>