10-10-2014, 02:04 PM
Pipelines are used extensively for transportation of fluids. Fluid velocity which
depends on the intended purpose, imparts energy to the pipe making it to
vibrate. Apart from this, pipes are supported in many ways. While indoor
piping are supported on structures, cross country piping used for transporting
petroleum products are either laid on ground or-buried. Good amount of
literature is available in the area of pipes conveying fluid with emphasjs on
stability aspects addressing critical flow velocities. However, the problem of pipe
conveying fluid resting on elastic medium has not been fully understood. A
modest attempt is made in this thesis to present an approximate analysis for the
problem of pipe conveying fluid resting on elastic medium.
In chapter - I, a brief review of, literature is presented highlighting the previous
contribution in the field of pipes conveying fluids. In addition the studies made
in the area of a beam on elastic foundation closely representing the situation of a
pipe on soil medium is presented. Various models used for this purpose have
been covered. Based on the review, the scope for the present study is presented.
In chapter - II, vibration of pipe conveying fluid resting on soil medium has
been studied modelling the soil medium as Winkler type.. Expressions are
derived for critical flow velocity and fundamental natural frequency with flow
velocity and soil stiffness as parameters for generally occurring pipe boundary
conditions namely hinged - hinged, fixed - hinged and fixed - fixed. Numerical
results are presented for various values of stiffness parameter, mass ratio and
velocity utilizing the data of a typical pipeline like Trans Arabian pipeline.
Improvements to the model of soil are made in chapter III by including the
inertia effect of soil. Frequency expressions obtained with this inclusion are
highly non-linear and are solved using nonlinear methods. Numerical results are
presented for various boundary conditions and values of soil inertia parameter,
stiffness parameter and velocity parameter.
In chapter - IV, an approximate design office procedure is developed to
compute the response of a pipe conveying fluid subjected to base excitation.
Numerical results are presented for hinged - hinged boundary condition for,
various values of velocity and soil parameters. The vertical component of the
Taft earthquake (1952), is utilized in obtaining the pipe response.
The thesis ends in chapter - V, with a brief summary, a -set of conclusions and a
few suggestions for future work.