Numerical and experimental evaluation of springback in a front side member

Abstract

Changes in geometry after springback are a major problem for the automotive industry. In order to make adjustments of the part to be formed, extra processes are needed. Since their implementation is both time-consuming and expensive, the industry would stand to gain if geometrical changes could be predicted at the time that the tool is being designed. Today, sheet-metal-forming simulations are, to a large extent, used to evaluate the forming process. Reliable results of the forming process can be obtained regarding, for instance, thinning, forces and fractures, but prediction of springback is not accurate enough to be fully reliable. Furthermore, the introduction of new, high strength steels, such as TRIP steels, emphasize the springback problem even more. This demands an increased ability to accurately predict the outcome of the forming process.In this study a part of an automotive side front section (front side member inner) was studied and a comparison both regarding material behaviour and of accuracy of the FE simulations was made. Mild steel, Rephos steel and TRIP700 were compared both experimentally and numerically. The results showed that TRIP steel has a significantly larger springback than the other materials. Furthermore, the FE simulations overestimate the twisting in this part for all materials, with the TRIP material showing the largest deviation between the experiments and the simulations. The prediction of punch forces was, however, accurate for all materials.

Automated design methodology for automobile side panel die using an effective optimization approach

“…Several analytical methods have been developed and used to investigate wrinkling and springback effects during forming processes [2][3][4]15]. Most of these methods have limitations in predicting formability characteristics accurately.…”

Experimental and numerical prediction of springback in V-bending of anisotropic sheet metals for automotive industry

“…Therefore, there may be problem in the production line, or in an accurate results of FEM in case of springback prediction. In different studies [24,25] authors highlighted the importance of work hardening and its influence on the springback amount and Three different categories of steel were used in experimental part of this work. One of these is a TRIP steel, which has significantly greater springback.…”

“…Therefore, there may be m in the production line, or in an accurate results of FEM in case of springback prediction. In different studies [24,25] authors highlighted the importance of work hardening and its influence on the springback amount and discuss about more accurate material description, for example mixed work hardening [24]. Considering this, several hardening curves and yield functions were used in this paper.…”

Characterising material and process variation effects on springback robustness for a semi-cylindrical sheet metal forming process

“…This problem is compounded by the introduction of advanced high-strength steels (AHSS) in many vehicle body structures. AHSS cause an increase in springback [3][4][5] and, perhaps, more concerning is the increased variation in springback from stamping to stamping that has been noted [6][7][8][9]. The increased magnitudes in springback can be compensated for by adjusting tool geometry and/or press settings.…”