Numerical investigation and dynamic behavior of pipes conveying fluid based on isogeometric analysis

Dynamic analysis and design of slender structures subject to different types of applied forces is of considerable practical interest in ocean engineering and aerospace applications. In this paper, the stability of pipes subjected to influences induced by fluid flow is investigated by using IsoGeometric Analysis (IGA). IGA aims to use the exact Computer-Aided Design (CAD) geometry and reduce the geometrical errors introduced by approximation of the physical domain of the problem. It uses B-Splines and Non-Uniform Rational B-Splines (NURBS) as basis functions and provides several advantages, which make it suitable for efficient and accurate simulations. The mathematical formulation of the problem is developed based on the Euler-Bernoulli beam theory (EBT) and the plug-flow model for the fluid forces. Both divergence and flutter instabilities are investigated. The numerical results are compared with those obtained by other available methods and it is shown that the results are in good agreement with lesser number of degrees of freedom, which is a fundamental criterion for the computational cost of an analysis. It is also confirmed that the IGA as described in the present paper, can be used efficiently to predict the possibility of divergence and coupled-mode flutter in dynamic analysis of pipes conveying fluid.