On surface stress and surface tension
1968; Elsevier BV; Volume: 12; Issue: 2 Linguagem: Inglês
10.1016/0039-6028(68)90118-0
ISSN1879-2758
AutoresJ. S. Vermaak, C.W. Mays, D. Kuhlmann‐Wilsdorf,
Tópico(s)Mechanical Behavior of Composites
ResumoThe physical significance of the difference between surface tension, σ, and surface stress, fij = δijσ + ∂σ∂eij, with δij the Kronecker delta, is investigated. It is concluded that the strain eij concerned is not the total strain, which may be composed of elastic and plastic contributions, but only the elastic component of the strain. It follows that the value of the surface stress depends on experimental conditions and it is concluded that measurements of surface stress are possible from the effect of the hydrostatic pressure due to all curved surfaces as well as from the mechanical forces exerted by planar surfaces of crystals, amorphous substances and liquids when the strain rates are sufficiently large so as to inhibit plastic deformation, causing the strains to be elastic. Conversely measurements of surface tension via mechanical forces exerted by surfaces require sufficiently slow strain rates so that all strains utilized in the experiment be fully plastic.
Referência(s)