Evolution mechanisms of residual stress in roll bending process for large-scale aerospace integral structures

Controlling residual stress distribution during roll bending is essential for manufacturing high-precision components, such as rocket propellant tanks. However, the mechanisms governing stress evolution in this process remain insufficiently understood, which limits the development of effective control strategies. This study introduces a novel full-scale finite element model of a 4.7 m rocket tank panel, rigorously validated against experimental stress measurements, to reveal the governing mechanisms of residual stress development. Unlike prior studies limited to small-scale or simplified geometries, this work systematically clarifies the coupled influence of roller down displacement and roller spacing on stress evolution. Two novel optimization pathways are identified: (i) intermediate roller displacement (15–20 mm) reduces peak residual stress by 15–20 % through suppressing localized deformation; and (ii) optimal roller spacing (500–550 mm) enhances stress uniformity, reducing equivalent plastic strain by 30–40 %. Moreover, combined parameter optimization (17.5–20 mm displacement with 500–550 mm spacing) lowers critical zone stresses below 30 MPa, significantly improving dimensional stability. These findings not only establish the first validated full-scale stress evolution model for roll bending but also deliver practical, quantitative guidelines for stress control in large aerospace structures.