I am investigating the effect of different structural properties on mechanical behavior of open-cell foams using compression tests. The structural properties that I have been considering are cell size, pore size, strut thickness as well as relative density. I am struggling on which surface area to consider for calculating the compression stress values, the "apparent" area which contains struts and pores (calculated by external dimensions of the specimens) or the "real" area which contains the struts only (and not pores). I wonder if the difference between the stress responses of two foams when the "real" areas are taken for stress calculation would be similar to the difference between the stress responses when "apparent" surface areas are taken to calculate the stresses. Don't you think taking the real areas (struts only) better reflects the difference between the mechanical responses of two foams with different structures? Are stress values calculated by the "apparent" area_ while the "real" areas are different_ comparable at all?
Thanks,
Reza
