Deformation of momentless shells under internal pressure under conditions where the material undergoes creep

Relations are derived for the deformation of momentless shells under internal pressure and finite strains. The law governing the deformation of the material is assumed to be that for a typical, incompressible viscoelastic solid. The special cases of the behavior of a spherical shell under a constant internal pressure and for a constant amount of gas in the shell are solved. It is found that up to a given limit, at constant pressure the deformation of the shell falls off, while above this limit the deformation increases at an increasing rate. With a constant quantity of gas inside the shell the deformation again falls off, as far as initial application of an internal pressure to the shell, equal to the critical, elastic pressure.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1066–1072, November–December, 1972.