Shape optimization of cantilevered columns subjected to a rocket-based follower force and its experimental verification

Abstract

Intended aims of the paper are, firstly to conduct a realistic structural optimization of a nonconservative system, and secondly to give an experimental verification of the theoretically predicted stabilizing effect of shape optimization of cantilevered columns subjected to a rocket-based follower force. Flutter of a cantilevered column having a small solid rocket motor at its free end is considered in this paper. The shape optimization for maximum flutter load was conducted computationally with the design constraint that the width of the column should not be less than half of the initial width, in order to keep test-pieces elastic during compressive loading. The theory predicts that the flutter parameter of the shape optimized column with constant volume can be 1.2 times higher than that of the uniform column. Then the corresponding experiment was conducted. The mean thrust produced by the rocket motor was assumed constant during firing. As the applied load in the experiment was constant the free parameter for loading was the length of the columns. The mean thrust was 580 N and the burnout time was 3.2 s. Five test runs were conducted to find the experimental critical length of the uniform test columns. Following this, two runs were made with optimum columns having the same lengths as the corresponding uniform test columns. As the outcome, an experimental verification was given to structural optimization of cantilevered columns subjected to a rocket-based follower force.