Objectives The study explores the law of bearing capacity of a typical pressure hull, using a cylindrical shell segment as the object, based on work on lightweight design technology in the pressure hull of an unmanned underwater vehicle.

Methods First,five typical materials were analyzed using the mechanical properties of the pressure hull, the load-bearing law and the optimal critical load-bearing design value (the stress strength failure and stability failure occur concurrently). The bearing properties of typical pressure hull with varying depths were then discussed further depending on the engineering requirements.

Results The failure mode of the shell gradually transitions from stability failure to strength failure as the depth grows, and the best critical load design value is proportional to material qualities. Considering the bearing efficiency and other factors, aluminum alloy shells should be selected within the 300 m depth range, titanium alloy and glass fiber composite shells within the 300-600 m depth range, and titanium alloy and carbon fiber composite shells within the 600-1 000 m depth range, in the 1 000-3 000 m depth range, a carbon fiber and boron fiber composite shell is the ideal solution.

Conclusions The findings can be used to guide the design of pressure hulls for UUVs made of various materials.