Effect of cell structure on elastoplastic behavior of closed-cell foam material

Abstract

This study conducts a numerical investigation to explore the influence of cell structure, relative density, and loading ratio on the elastic and plastic properties of closed-cell foam materials under uniaxial and multiaxial loadings. The characteristic stress-strain curves of closed-cell foam with the relative density, inner cell structure, and loading ratio are compared. Since the mechanical properties of foam materials are mainly affected by large pores, we applied the parameters: the characteristic diameter Dch and characteristic shape anisotropy αch proposed by Ref.40,41 to measure large pore size and shape in order to analyze. For better comparison, we have normalized the characteristic stress-strain data based on the uniaxial yield strength. Our findings indicate that the impact of relative density under trial loading is more significant than that under uniaxial loading. And the characteristic diameter Dch has virtually no effect on the dimensionless characteristic stress-strain curve. The characteristic shape anisotropy αch has minimal impact on the distribution of the characteristic stress-strain curves under uniaxial loading, in constract, for various values of characteristic shape anisotropy αch, significant disparities can be observed. Therefore, the early-stage elastoplastic behavior is also affected by the loading ratio. Furthermore, the stress-strain curve under different loading conditions can be modeled using Eq. 15. The parameters in Eq. 15 are determined by the loading parameters cos (3θ) and k.