Thin wall approximation revisited

Abstract A thin wall mechanical framework for calculation of stresses, strains and displacements, e.g. in fuel rod cladding deformed plastically by contact with expanding fuel pellets, is proposed. The standard thin wall approximation to exact elastic solution of a long closed cylindrical tube loaded by inner and outer pressure is extended by considering displacement boundary conditions at inner or outer radius instead of inner pressure. A suitable projection of strains enables application of displacement boundary conditions, as well as treatment of tube dimensional changes in this thin wall framework. Applications to several problems relevant for fuel cladding deformations are discussed. Analytical solution of the problem of partially plastic tube and FEM simulations of mechanical tests are utilized to assess the quality of the proposed approach.