190
S. Ruan et al.
Figure 15.8 shows the thinning contour of the thickness thinning after end expansion. A 5% thinning is observed at the both ends while a slight thicken is found in
the middle region. Besides, the thinning contour after press bending is also shown in
Fig. 15.9. In this step, the thickness change concentrates in the middle region. The
inner side of the bending direction is thickened further while the wall thickness of
the out side reduces about 3%. No obvious risk of crack nor wrinkle is found in the
bending step.
In addition, the thickness distribution of the pre-forming is shown in Fig. 15.10.
It can be seen that the most thinning area has a thickness more than 3.2 mm, which is
about 8% thinning. And most thickened areas locate on the top of the V-shape in the
inner side of the bending, where the material flowing is hindered by the die surface.
The cold forming simulation result is transferred to the hot gas forming simulation with a dynain file, which includes positions of the nodes, the stress and strain
information of the elements, as well as the thickness.
Fig. 15.9 Current thinning contour after press bending
Fig. 15.10 Thickness distribution after cold forming process
S. Ruan et al.
Figure 15.8 shows the thinning contour of the thickness thinning after end expansion. A 5% thinning is observed at the both ends while a slight thicken is found in
the middle region. Besides, the thinning contour after press bending is also shown in
Fig. 15.9. In this step, the thickness change concentrates in the middle region. The
inner side of the bending direction is thickened further while the wall thickness of
the out side reduces about 3%. No obvious risk of crack nor wrinkle is found in the
bending step.
In addition, the thickness distribution of the pre-forming is shown in Fig. 15.10.
It can be seen that the most thinning area has a thickness more than 3.2 mm, which is
about 8% thinning. And most thickened areas locate on the top of the V-shape in the
inner side of the bending, where the material flowing is hindered by the die surface.
The cold forming simulation result is transferred to the hot gas forming simulation with a dynain file, which includes positions of the nodes, the stress and strain
information of the elements, as well as the thickness.
Fig. 15.9 Current thinning contour after press bending
Fig. 15.10 Thickness distribution after cold forming process