High temperature mechanical behavior of tube stackings - Part II: Comparison between experiment and modeling

This paper is the second part of a set of two papers dedicated to the mechanical behavior of cellular materials from room temperature to high temperatures. For that purpose, some monotonic and creep compression tests have been performed on a small tube stacking structure. In parallel, a finite-element model of these experiments has been proposed, using the constitutive elasto-viscoplastic behavior identified for the tube material in Part I [1] as input data. The comparison between the experiment and the modeling has provided many items of information regarding the collapse mechanisms of this kind of cellular structure at high temperatures and the role of the contacts created between the tube walls at large deformations. Especially, a competition between both relaxation and hardening phenomena locally has been revealed at high temperatures, resulting in some softening of the stacking effective behavior.