Breakage of the adherend
To determine the strength of adhesive bonds, standard test specimens are bonded in the laboratory. The adherend fracture is a specific type of fracture of these standard test specimens.
A distinction is made between the following types of fracture:
- Fracture between adhesive and adherend: adhesive fracture (adhesion)
- Fracture in the adhesive: cohesive fracture (cohesion)
- Breakage of the adherend
- Various forms of mixed herd
- Material tearing, material delamination (e.g. with fiber-reinforced plastic).
If the break occurs entirely outside of the adhesive layer, the strength of the adhesive is greater than the inherent strength of the parts to be joined or the broken part to be joined.
This fracture is referred to as a cohesive fracture in the adherend material or simply as a fracture of the adherend.
In contrast to a boundary layer break on the part to be joined, a break in the part to be joined runs completely through the material of the part to be joined that is not affected by the bonding.
