Random loading on a spherical pressure vessel of Hooke-Norton material

A spherical pressure vessel of non-linearly viscoelastic material (Hooke-Norton type) is analysed. The internal pressure consists of a small randomly varying part superposed on a constant part. A perturbation technique is used to find stresses and deformations. The effect of the redundancy of the system on stresses and deformations is studied, and a simple approximate method is suggested for the slightly redundant case of a thin-walled sphere.