The interactive effects of wrinkling and other defects in thin-walled tube NC bending process

The thin-walled tube NC bending process is essentially a tri-nonlinear complex physical forming process with multi-factors coupling interactive effects. Three general defects in the sheet forming process are all observed in the bending process, such as wrinkling instability, over thinning (cracking), cross-section distortion, which makes it difficult to select the optimal forming parameters to solve all the above defects simultaneously due to the interactive effects between wrinkling and other defects. In the study, the interactive effects of the wrinkling and other two defects in the process are first proposed and investigated by using the developed Explicit FE model based on the ABAQUS/Explicit code. A strategy for selecting the positive parameters is proposed based on the understanding of the interactive effects of wrinkling, thinning and section distortion. The results help to the design and optimization of the process.