To determine the strength of adhesive connections, standard test specimens are bonded in the laboratory. The component fracture is a specific type of fracture of these standard test specimens.

A distinction is made between, among others, the following types of fracture:

• Break between adhesive and part to be joined: adhesive break (adhesion)
• Fracture in Adhesive: Cohesive Fracture (Cohesion)
• Breakage of the joining part: Breakage of the joining part
• Different forms of mixed fracture
• Material tear-out, material delamination (e.g. in fiber-reinforced plastic).

If the break occurs entirely outside 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 material to be joined or simply as a fracture to the joined part.
In contrast to the boundary layer fracture on the part to be joined, a part to be joined runs completely through the material of the part to be joined, which is unaffected by the bonding.