2009 Volume 3 Issue 1 Pages 351-362
In this paper, telescopic deformations of stepped circular tubes are studied by axial compression with finite element method. It is found that three-stepped circular tubes can be considered as a combination of two two-stepped circular tubes, from which the compression load for a three-stepped cylinder can be predicted in approximation from the loads for the two-stepped cylinders. However, the predicted values by this technique are higher than those of the three-step cylinder, because the restraint of the vertical wall in the two-stepped cylinders is larger than that in the three-stepped cylinder. The mechanism of the telescopic deformation of stepped circular tube is mainly composed of bending, rotating, and stretching of the tube wall. However, another mechanism has appeared when the radius difference of the small and the big cylinders is small enough. As far as geometric parameters concerned, the average load of a two-step cylinder goes up as the radius difference ΔR decreases and as the cylinder height H or the thickness t increase. And, the initial load grows with the increase of fillet radius. Further, the average of compressive load is also investigated.
