Viscoelastic layered cylinder in vertical storage

Abstract

The problem of creep of a solid-fuel rocket engine under the action of its own weight when stored in a vertical position is considered. The purpose of the work is to study the stress-strain state of the engine, to determine the areas of localization of stresses and strains, in particular, radial tensile and tangential stresses at the cylinder-shell interface. The engine is modeled as a hollow cylinder with a circular cross-section made of a linear isotropic thermo-rheologically simple viscoelastic material supported on the lateral surface by a three-layer elastic shell. The relaxation function of the cylinder material under uniaxial tension is represented by the sum of exponents, and the volumetric deformation is assumed to be elastic. The problem is solved using the Schapery approach, which reduces the viscoelastic problem to an elastic problem with time-varying moduli. The problem transformed in this way is solved by the finite element method. A quadrilateral isoparametric element is used. The distributions of current and time-steady-state stresses and creep strains at certain points in the engine volume are investigated. It is established that the maximum stresses in the cylinder are localized in the vicinity of the corner points of the cylinder-shell boundary, where a singularity of stresses occurs in the linear formulation. In the same areas, the maximum values of tensile radial and tangential stresses are reached, which are dangerous from the point of view of charge detachment from the casing. Significant values of axial compressive stress occur in the lower support part of the cladding. The largest are the shear deformations of the cylinder along the contact boundary with the cladding. The creep curves at the cylinder points at room temperature are plotted. The estimation of the characteristic creep settling time is given.

Pages of the article in the issue: 82 - 85

Language of the article: Ukrainian