Crash boxes

There are two principal types of crash boxes, the folding box and the shear box. Here are two examples:

Folding box, BMW E-65, specification:

Weight: 0.66 kg

Functional description: The energy is absorbed as the two-chamber tube starts folding. The folding force is smoothed as the chambers partly fold in anti-phase.

Material: EN AW-7003

Process: Extrusion and sheet are reformed, punched and welded together.

Shear box, Audi B6, specification

Weight: 450g

Functional description: The energy is absorbed as two steel bolts shear along the imprinted grooves in aluminium crash box. The shearing force is uniform along the shear distance.

Material: EN AW 6063

Process: Extrusion is reformed by setting embossments and making holes.