Title:An alternative approach for the analysis of non-linear vibrations of pipes conveying fluidAuthor(s):Michael Stangl, Johannes Gerstmayr, Hans IrschikAbstract:Based on a novel extended version of the Lagrange equations for systems containing non-material volumes, the non-linear equations of motion for cantilever pipe systems conveying fluid are deduced. An alternative to existing methods utilizing Newtonian balance equations or Hamiltons principle is thus provided. The application of the extended Lagrange equations in combination with a Ritz method directly results in a set of non-linear ordinary differential equations of motion, as opposed to the methods of derivation previously published, which result in partial differential equations. The pipe is modeled as an Euler elastica, where large deflections are considered without order of magnitude assumptions. For the equations of motion, a dimensional reduction with arbitrary order of approximation is introduced afterwards and compared to existing lower order formulations from the literature. The effects of nonlinearities in the equations of motion are studied numerically. The numerical solutions of the extended Lagrange equations of the cantilever pipe system are compared to a second approach based on discrete masses and modeled in the framework of the multibody software HOTINT/MBS. Instability phenomena for an increasing number of discrete masses are presented and convergence towards the solution for pipes conveying fluid is shown.Journal:Journal of Sound and VibrationPublisher:Elsevier Ltd.ISSN:0022-460XPage Reference:page 493-511, 19 page(s)Publishing:2/2008Volume:310