Experimental verification of the effect of rocket thrust on the dynamic stability of cantilevered columns.

摘要

This thesis deals with the dynamic stability of cantilevered columns subjected to a follower force. The aim of this thesis is to give experimental verifications of the effect of follower forces which are realized by real rocket motors. Several experiments were conducted to give experimental verifications of the nonconservative problem of elastic stability. Small-sized solid rocket motors were mounted to cantilevered columns at their tip ends to apply a tangential follower force to the columns. It is worthwhile to note that these experiments are the first tests in the world to give direct experiment verifications of the nonconservative problem by using real rocket motors for a follower force. Some important conclusions have been obtained through the experiment and theory in the present thesis.; This thesis comprises (1) an experimental investigation on the flutter of horizontal cantilevers subjected to a tangential follower force; (2) the effect of an intermediate concentrated mass on the flutter of horizontal cantilevered columns subjected to a rocket thrust, both theoretically and experimentally; (3) the experimental verifications of stabilizing effects of follower force on stability of cantilevered columns which is initially subjected to conservative loading. In order to verify experimentally the effect of follower force on the stability of the column, a tangential follower force is realized by a direct installation of a real solid rochet motor at the tip of the column.; The conclusions drawn from this study are (1) it is confirmed that the columns lost their stability by flutter and the concept of stability in a finite time interval was successfully introduced to predict the theoretical flutter (2) destabilizing effect of a intermediate concentrated mass is demonstrated by theory and experiments; (3) it is observed experimentally that the cantilevered columns were stabilized by the action of rocket thrust when the columns were subjected to rocket thrust in addition to a dead load, in spite of the fact that the resulting total compressive load was increased greatly.