Part VII. Experimental approach to nonconservative stability problems

The intended aim of this part is to give some experimental supports to nonconservative stability problems. Chapter 1 describes the state of art of dynamic stability of elastic systems subjected to nonconservative follower forces. Experimental works are specially emphasized. Chapter 2 is concerned with flutter of cantilevered pipes conveying fluid. The combined effect of a spring support and a lumped mass on stability of a tubular cantilever conveying fluid is discussed. It is shown theoretically and experimentally that for particular combinations of a spring support and a lumped mass, there exists a flutter peninsula, which juts out locally from the main flutter region. Chapter 3 aims at showing experimental verifications of the reality of follower force. Three experiments are presented on dynamic stability of cantilevered columns subjected to a follower force produced by a solid rocket motor. The first experiment shows that a horizontal cantilevered column subjected to a rocket thrust loses its stability by flutter. The second experiment gives an experimental support to the effect of an attached lumped mass on flutter of horizontal cantilevered column. The third experiment demonstrates the reality of sub-tangential follower force. Chapter 4 discusses the effect of damping configuration on flutter of two-degree-of-freedom mechanical models subjected to a Reut-type nonconservative force. The nonconservative force was produced by an impinging air jet. Damping due to an attached dash-pot is taken into account, as well as internal and external damping. Chapter 5 describes the general concluding remarks. In Appendix are shown some photographs of experiments on dynamic stability of cantilevered columns subjected to a rocket thrust.