Shear Modulus, Effective Viscosity, and Yield Stress

Shear Modulus, Effective Viscosity, and Yield Stress 

Shear modulus. One of the most important characteristics of the foam elasticity is the shear modulus G, which is the coefficient of proportionality between the tangential stress t in solid-shaped foam (t to) and the shear strain 7. This variable was theoretically calculated by Derjagin [115] 

If we estimate the specific interfacial area e for a monodisperse foam by formula (7.1.4), then we can rewrite this relation as 

Later on Khan [225] also theoretically obtained the following estimate for the shear modulus of dry two-dimensional foam under the assumption that the foam cells are regular hexagonal cells and the deformation is not small  

We believe that the following semiempirical Princen-Kiss formula [380] is most reliable for practical computations  

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