mechanical behaviour of thick multilayered cylinders. The original contribution of this
work is to provide novel approximate analytical solutions to compute the timedependent
internal stress state throughout the pipe thickness within the framework of
nonlinear viscoelasticity theory. The structures considered are thick, multilayered

anisotropic infinitive long cylinders subjected to axisymmetric mechanical loading.
Under such conditions there is an exact elastic solution which naturally satisfies
equilibrium, strain-displacement, compatibility and boundary conditions for the stated
constitutive equations and loading. Due to the continuous stress variations throughout
the cylinder thickness, the proposed nonlinear viscoelastic solution assumes the
averaged stress state to calculate the nonlinear elastic and viscoelastic factors in each
3
layer. Furthermore the solution is obtained assuming that the creep strains, within each
layer, are constant through the thickness. The proposed algorithm converges to the exact
solution when the number of layers is artificially increased. For the linear viscoelastic
case the proposed solution proved to match the exact known solution for isotropic

یک مطلب دیگر :

viscoelastic materials. Finally several invented cases are run to illustrate the importance
of the viscoelasticity phenomenon on the internal stress field throughout thick laminated
cylinders.
KEYWORDS: Polymer–matrix composites (PMCs); Creep; Elasticity; Analytical
modelling; Durability.
INTRODUCTION
The hollow cylinders or cylinders are very common structural elements, used in many
applications including trusses, hoses, piping systems and drive shafts. The effort to
improve oil production riser performance lead to the possible use of risers made of
polymer matrix composites to bring the oil to surface platforms in the offshore
exploration at waster depth of 2 km or more. Consequently the increasing use of
polymer matrix composites in civil engineering applications has renewed interest in
problems of stress analysis of cylindrical laminated composite structures.
Many analytical works about stress analysis of composite cylindrical shells have been