Size effects on deformation behavior of ultra-thin-walled corrugated sheets in roll bend forming process

The corrugated sheet is a crucial component of the metal honeycomb structure. This study investigates the size effects on the deformation behavior of ultra-thin-walled corrugated sheets in the roll bending process using experimental and simulation methods. A precision roll bending device was developed, which incorporated a specifically designed eccentric fine-tuning module and a pneumatic module to prevent the distortion and insufficient deformation of the ultra-thin-walled corrugated sheets. The experimental results showed that micro-scratches and orange peel phenomenon appeared in the bending region of ultra-thin-walled corrugated sheets due to the lack of grain deformation coordination. Decreasing the ratio of foil thickness to grain diameter ( t / d value) resulted in a slight increase in edge lengths, but a sharp decrease in the thickness of the bending region of ultra-thin-walled corrugated sheets. For the ultra-thin-walled corrugated sheet with a t / d value of 1.2, its thickness was reduced by 14%, leading to a high risk of rupture. Consequently, a finite element model of the roll bending process was established with consideration of the heterogeneity of grain shape and grain orientation. The simulation results indicate that the prediction error of the model for the springback angle was less than 15%. The random distribution of elastic deformation and plastic penetration zones is responsible for the great scatter of the springback angle of ultra-thin-walled corrugated sheets. This research provides a theoretical foundation for the precision manufacturing of ultra-thin-walled corrugated sheets.