Advances in Springback

The number of through‐thickness integration points (NIP) required for accurate springback analysis following sheet forming simulation is the subject of confusion and controversy. Li and Wagoner recommended, in 1999, based on a finite element analysis (FEA) of draw‐bending springback, the use of 25 integration points (IP). They also reported that up to 51 IP could be required to obtain springback solutions with accuracies of 1%. Several researchers since then have reported that NIP between 5 and 11 are adequate, and even that 7 or 9 IP are optimal, with reduced accuracy for more IP. These apparent contradictions are addressed with an analytical model of elasto‐plastic bending under tension, followed by elastic springback. The fractional error in the evaluated bending moment, which is equal to the fractional error in springback, was determined by comparing three numerical integration schemes, with various NIP, to the closed‐form result. The results illustrate the oscillatory nature of numerical integration ...