Collapse Tests on Externally Pressurized Toroids

Abstract

The paper discusses the load-carrying capacity of toroidal shells with closed circular cross section and loaded by static external pressure. Details about the manufacturing, pre-experiment measurements and testing of three, nominally different, steel toroids are provided. Two of them were manufactured from mild steel by spinning two halves and then welding them around the inner and outer equatorial perimeters. The third one has been assembled by welding four 90-deg stainless elbows. The outer diameter of these models was about 300 mm and the wall thickness varied from 2.0 to 3.0 mm. The hoop radius-to-thickness ratio, r/t, varied from about 15 to 30. The experimental collapse pressures were in the range from 4 to 8 MPa. Comparisons with numerical results are also provided.