Abstract

The main aim of this paper is to assess and compare the relative importance of the effects of considering the fluid presence and the bond imperfection while evaluating the non-axisymmetric dynamic response of an imperfectly bonded empty as well as fluid filled orthotropic thin cylindrical shell buried under soil and excited by compressional wave (P-wave). While applying thin shell theory, the effect of shear deformation and rotary inertia need not to be considered. The pipeline had been modeled as an infinite cylindrical shell imperfectly bonded to surrounding. A thin layer is assumed between the shell and the surrounding medium (soil) such that this layer possesses the properties of stiffness and damping both. The effects of the fluid presence on the shell displacement have been studied for different soil conditions and at various angles of incidence of the longitudinal wave. It is observed that magnitude of the dynamic response of fluid filled pipeline is more than that of an empty pipeline. Axial and radial deflection of thin pipe is considerable even under hard soil conditions under imperfect bonding of pipe with soil. Numerical results have been presented for the longitudinal compressional wave (P- wave) only.

Key words: Orthotropic, Imperfect bond, seismic wave, non-axisymmetric, dynamic response, buried pipelines, thin shell.