Prediction of positive and negative elastic dilatancy in 2D and 3D liquid foams

Liquid foams have been observed to behave like immersed granular materials in at least one respect: deformation tends to raise their liquid contents, a phenomenon called dilatancy. We present a geometrical interpretation thereof in foams squeezed between two solid plates (2D GG foams), which contain pseudo Plateau borders along the plates, and in 3D foams. While experimental observations evidenced the effect of a continuous deformation rate (dynamic dilatancy), the present argument applies primarily to elastic deformation (static dilatancy). We show that the negative dilatancy predicted by Weaire and Hutzler (Phil. Mag. 83 (2003) 2747) at very low liquid fractions is specific to ideal 2D foams and should not be observed in the dry limit of real 2D foams. PACS numbers: 83.80.Iz Emulsions and foams – 83.60.Hc Normal stress differences and their effects – 45.90.+t Other topics in classical mechanics of discrete systems Electronic address: [email protected] Electronic address: [email protected] Electronic address: [email protected]