Analysis of the dynamic stability of collar-stiffened pipes conveying fluid

The dynamic stability of a collar-stiffened pipe conveying fluid was examined by using the Euler-Bernoulli beam theory. The pipe considered consists of identical substructures, or cells, connected in an identical fashion. Each substructure, or cell, comprises a uniform pipe segment and a collar, A finite element model was developed to predict the dynamic stability of the stiffened pipe under the action of the flowing fluid. Stability maps were obtained for clamped-free collar-stiffened pipes of various design parameters. The design parameters included the arrangement and the geometry of the identical cells. The stability maps demonstrated that the collar-stiffened pipe exhibits unique stability characteristics when compared to a uniform pipe. It was found that the stable region in the stability map enlarges for the collar-stiffened pipe when compared to a uniform pipe. To give clearer insight into the pipe dynamic behavior, the dynamic response and eigenvalue branches were presented for a number of collar-stiffened pipes. (c) 2006 Elsevier Ltd. All rights reserved.