3. Two textbook cases

Whether the aim is to predict the foam's rheological properties or to assess its overall expansion, we must return to solving the problem of mechanical equilibrium of the mixture in the mold. The mechanical behavior of foam depends primarily on its compressibility and rheological evolution. Predicting the mechanical evolution of foam therefore requires the definition of a behavior law and a number of assumptions.

• Main assumptions

  • The mixture is assumed to have viscoelastic behavior. A Maxwell-type mechanical behavior law is used.

  • Temporal changes in mixture viscosity (and elasticity) are assumed to be known (they are a function of chemical reactions, but chemo-rheological couplings are not explicitly introduced at this level).

  • ...