Experimental and numerical analysis of springback prediction in U-bendings of anisotropic sheet metals

Abstract

Springback is one of the most important problems that should be taken into consideration during design of sheet metal forming process with the increasing application of advanced high strength steels and light-weight alloys. The degree of springback experienced with the latest generation materials is so high, and the materials so strong, that it is not possible to eliminate the springback in the prototyping. It becomes mandatory to compensate for springback as part of the draw die design, which is usually carried out through numerical simulation. The springback behavior of three categories of sheet steels (TRIP, HSLA and mild steel) with thicknesses ranging from 0.75 to 0.85 mm was investigated by means of the cyclic U-bending test. This phenomenon can be defined as an elastically-driven change of shape of the deformed part upon removal of external loads. Steel sheets were bent on the two different die radii and after first cycle were bent reverse. The influence of die radius on amount of springback of the steels was considered. Value of the springback angle change after the first and second cycle was measured. The change of values of angles between cycles is caused by the Bauschinger effect. This process was investigated experimentally and numerically. Numerical investigation was performed in static implicit finite element code Autoform.

An Alternate Method to Springback Compensation for Sheet Metal Forming

“…The results show a good reduction in springback, but this method is applied and tested in the L-bending only. The U-bending model is analyzed by Slota et al [ 14 ] in both numerical and experimental analyses. The experimental analysis is conducted by using specimens of steel DC06, UHSS TRIP RAK 40/70, and HSS H220PD in orientations 0°, 45°, and 90°.…”

An experimental investigation of formability of inconel sheet plate for different die angles and rolling directions in press brake bending

“…There are some researches in literature realized by experimentally [26] and/or numerically [27,28] to investigate the spring-back behavior of the materials in different types of bending processes [29]. Kumar et al determined spring-back amount of aluminum sheet metal by using process of L -bending according to the gap between punch and die.…”