2020 Volume 61 Issue 710 Pages 63-68
A new press-forming technique using in-plane shear deformation was developed for suppressing fractures and wrinkles of curved shapes in the height direction, for automobile body parts such as the front-side member rear. The developed technique is a two-step processes, draw-forming to induce in-plane shear strain and bending into a curved shape. From experiments on a simplified curve part, in-plane shear deformation which is effective for suppressing fractures and wrinkles occurred in the first process when the press stroke changed along the longitudinal direction of the part. When the induced in-plane shear deformation was increased, a part with a higher curved angle in the height direction could be formed in the second process. Then, we conducted press trials of a front-side member rear model using a 1180 MPa-grade ultrahigh-strength steel sheet to evaluate the effectiveness of the developed technique. The results suggested that a complex curved part could be formed without fractures or wrinkles when in-plane shear deformation was induced in the first process.
