Objective In order to explore the characteristics of optimization design schemes of titanium alloy double layer stiffened cylindrical shell structures under different length-to-diameter ratios and calculation pressures, a mathematical model for the lightweight optimization of such structures is established.

Methods The main control program of the genetic algorithm is established in MATLAB, and the ultimate bearing capacity is calculated and checked by finite element software ANSYS. The differences of optimization schemes between titanium alloy single layer stiffened cylindrical shells and titanium alloy double layer stiffened cylindrical shells under different length-to-diameter ratios and different calculation pressures are then compared and analyzed.

Results There are two critical calculation pressures in the optimization design of titanium alloy stiffened cylindrical shells, and the optimization design is divided into three types: the stability constraint type of ultimate bearing capacity constraint control optimization design, the strength constraint type of strength constraint control optimization design, and the joint constraint type of strength and ultimate bearing capacity constraint joint control optimization design. The larger the length-to-diameter ratio, the greater the critical calculation pressure. Under the same calculation pressure and length-to-diameter ratio, the weight of the double layer shell optimization scheme is lighter than that of the single layer shell, and the critical calculation pressure of the double layer shell optimization design is smaller than that of the single layer shell under the same length-to-diameter ratio.

Conclusions The results of this study can provide useful references for the optimization design of titanium alloy double layer stiffened cylindrical shell structures.