Vijay Gautam

Experimental and numerical investigations on springback in V-bending of tailor-welded blanks of interstitial free steel

Tailor-welded blanks of interstitial free steel are commonly used in complex automotive skin panels. The presence of weld zone, difference in thickness and high anisotropic behaviour affect forming behaviour of tailor-welded blanks significantly. Therefore, incorporation of anisotropy of the sheets and properties of the weld zone in finite element simulations is very important for accurate prediction of springback in bending of tailor-welded blanks. In this study, experimental and finite element simulations of V-bending were carried out on tailor-welded blanks of three thickness combinations, prepared by Nd-YAG laser welding of interstitial free steel sheets of thicknesses 0.8, 1.2 and 1.5 mm. The orientation of the weld line in longitudinally welded blanks was kept at 0°, 45° and 90° with respect to the rolling direction to study the effects of anisotropy on springback in V-bending. The tensile properties of the weld zone in different thickness combinations were determined and incorporated in finite element simulations for prediction of springback. It was observed that springback results were mainly governed by the springback behaviour of the thicker sheet in a particular thickness combination. Weld zone properties affect the springback of tailor-welded blanks more significantly than the anisotropy of the sheets. Accuracy of predicted values of springback in simulations increased when the properties of the weld zone were incorporated in the material model.

Effect of Plastic Strain on Anisotropic Behaviour of AISI202

Aims: In the present study an attempt has been made to determine the effect of plastic strain on the anisotropic parameters of AISI202 series. Study Design: The parameter commonly used to characterize the an isotropy of sheet metal is the plastic strain ratio i.e. the ratio of true width -strain to thickness -strain. Accurate determination of

Effect of Punch Profile Radius on Springback in V-Bending of Tailor Welded Blanks Welded in Transverse Direction

Tailor welded blank (TWB) is an advancement in the field of sheet metal forming in which multiple blanks are welded together to create a single blank prior to forming process. Springback behaviour of TWBs in bending is complex due to thickness or material combination. In this research, the effect of punch profile radius on the springback of transversely welded strips has been investigated in V-bending operation with included bend angle of 90° and using punches with three different punch profile radii of 7.5, 10and 12.5 mm. TWBs were prepared by laser welding of interstitial-free steel blanks with a thickness combination of 0.6 and 1.2mm. The Tensile properties of parent materials and tailored blanks were evaluated by Tension test as per ASTM-E8M standard. The bend samples with transverse weld line were prepared to a size of 20X150mm to ensure plane strain bending. Finite element (FE) simulations were performed using Abaqus and were found to be in good agreement with the experimental results.