3.2 Load types

Compressive and  tensile stress / load

These forces act perpendicular to the  bonding area.
In principle unproblematic, but the  bonding area is often too small.

Shear  stress.

The force acts parallel to the  bonding area.
Bonded joints should be designed for this force.

Peel  stress.

Line shaped  stress, namely the force acts along the  bond width.
Peel  stress must be absolutely avoided!

Source: IVK

Types of stresses/loads:

  • Mechanical stresses (uniaxial or multiaxial)
    • Static (shear, compressive, tensile, and torsional stresses)
    • Dynamic
      • Cyclical stress
      • Shock, impact and crash loads
  • Media
  • Radiation
  • Temperature

Cyclical stress: Cyclic repetition of a specific mechanical s‌tress
Although even a single load can lead to damage to the adhesive, multiple cycles with the same load are more likely to cause damage (material fatigue).
Can have different effects depending on the intensity (deflection (amplitude) and number of cycles (frequency)), direction and the nature of the bonded joint.

Impact stress: Arises due to the acceleration or retardation of masses; usually no regular repetition.
Can have different effects depending on the intensity (force and speed), direction and the nature of the bonded joint.

Media loads: These include chemicals such as cleaning agents and also moisture. Important factors are the duration of action, temperature and in some cases the concentration of the medium.

Radiation: Usually natural UV radiation, but in special cases x-rays or other radioactivity.