Static Shear Modulus of Gas–Liquid Foam Determined by the Punch Indentation Test
✍ Scribed by Mark F. Coughlin; Edward P. Ingenito; Dimitrije Stamenović
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 157 KB
- Volume
- 181
- Category
- Article
- ISSN
- 0021-9797
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✦ Synopsis
NOTE
Static Shear Modulus of Gas-Liquid Foam Determined by the Punch Indentation Test
where S is the total interfacial surface area, u is shear strain, and subscript 0 denotes the reference configuration; DP Å 2g 0 S 0 /3V 0 , where V 0 is the The punch indentation test was used to measure the static shear volume occupied by foam at the reference configuration. Equation [1] indimodulus (m) of shaving foam. Surface tension of the foaming cates that m is entirely determined by DP and by the geometrical features liquid, the mean foam cell diameter, and the volume fraction of the of the microstructure. Most theoretical studies of foam shear modulus m dispersed phase (f) were measured to determine the overpressure have been focused on determining Ì 2 (S/S 0 )/Ìu 2 É 0 using either different (DP) in foam cells. It was found that with increasing foam age m bubble geometries or assuming kinematics of liquid surfaces. decreased, reaching a steady value of Ç0.18DP when f Ç 0.94. Derjaguin (2) pictured foam as a network of interconnected flat liquid This is lower than the lowest values measured previously in gasfilms of equal g. By assuming that those films follow the affine strain field, liquid foams by nearly a factor of two. A possible reason could he obtained that m/DP Å 0.4. Stamenovic ´and Wilson (6) pointed out that be reduced artifacts and dynamic effects present in the previous the predicted value of 0.4 is an upper bound since the affine strain need measurements. This value agrees with values measured in oil-innot satisfy equilibrium at foam Plateau-Gibbs borders. Budiansky and Kimmel (8) obtained a much smaller value of m/DP Å water emulsions (J.