Collapse of Externally Pressurized Steel–Composite Hybrid Cylinders: Analytical Solution and Experimental Verification

To evaluate the collapse pressure of the steel–composite hybrid cylinders under external pressure without excessive computational cost, an analytical formula was derived in this study. The rationality of the derived formula was verified by the comparison with experimental and numerical results. The experimental results indicate that samples are manufactured and tested with good quality. The derived formula considered material failure and could reasonably predict the collapse pressure of the steel–composite hybrid cylinders with a maximum difference of 3.1%. Moreover, the effects of the wrap angle, thickness, and length on the collapse pressure of the hybrid cylinders were theoretically analyzed. The loading capacity of the hybrid cylinders was maximized under a wrap angle of ±55° for the composite layer. These findings are mainly because the hoop stress is twice the value of axial stress for a cylinder under uniform pressure