The first uses two pieces that are joined together. Here, the risk of the sharp corners and the weld quality will be critical. In contrast, the second solution uses only one part, which is bent. This solution will have some bending radii limitations. But instead, there will be no sharp corners, which will have a positive effect on load distribution and fatigue.

Two-piece component (left) vs. one-piece component (right).

As the illustration below shows, a box design will probably need to consist of two or three parts, while the U-shape will only need one part. However, the U-shape brings with it a higher bending cost.

The box profile will instead have a welding cost associated with it, and the corner welds will always involve a critical moment. In terms of load distribution, the U-shape design will have better load distribution than the box design. Additionally, the box design entails both higher welding and higher cutting costs, but lower bending costs compared with the U-shape.

Three-piece box tipper section (left) vs. one-piece U-shape tipper section (right).