Modeling of failure mechanisms using the true stress-strain response of polymeric foam materials

Polymeric foams are widely used in various engineering applications. Understanding and quantitative modeling of foam load-displacement behavior is important for design and development of engineering structures with foams. In this paper we analyze three main micro-mechanisms of foam macroscopic deformation and failure using stress-true-strain diagram of loading cycle. Specifically, connection between 1) large reversible deformation and buckling, 2) large elasto-plastic deformation and 3) brittle fracture of individual cell structural elements on one side and macroscopic foam behavior on the other is discussed. Identification of specific micro-mechanism responsible for macroscopic behavior foam is suggested on the basis of detailed analysis of unloading part of stress-true strain diagram, i.e., strain recovery process.