Department Structural Durability and System Behavior

(Professor Dr.-Ing. Alfons Esderts)

Fatigue analysis (or structural durability) deals with the estimation of the service life of components that have to endure cyclic loading, which is a common load case.

The foci of the professorship are summarized underneath:

• Experimental fatigue life assessment:
  An experiment is conducted, during which the component in question is exposed to a realistic loading situation. The loading is imposed on the component by one or multiple actuators, aiming for the simulation or prediction of a realistic damage behavior in the lab. Thereby it becomes possible to derive the allowable period if use or the allowable amount of load. The IMAB therefore is equipped with a multitude of different actuators (servo-hydraulic, servo-pneumatic, mechanical, as well as resonance testing machines) and thereby is able to test components and materials by using loads ranging from a few Newtons up to 500 kN.
• Analytical fatigue life assessment:
  Since experiments in the field of fatigue analysis are both cost and time intensive, methods have been developed to analytically model the different mechanisms that lead to fatigue failure. The IMAB distinguishes itself by a longstanding expertise in simulation and programming of such analytical tools for lifetime estimation. However, for being able be to apply these tools successfully, some experiments (e.g. material testing) are often necessary.
• Load assumption:
  An essential part of fatigue analysis is the experimental determination of cyclic loads that can finally lead to fatigue failure. This type of experimental determination of loads during operation and especially at moving components or systems requires complex measurement technology, which is available at the IMAB. Besides the experimental determination of loads, the department also covers simulation methods for load assumptions as e.g. multibody simulation of complex systems.

During the past years, the following topics have been in scope of the research activity at IMAB: manufacturing influences of the material behavior, influences of multiaxial loads, reliability of components, fatigue life assessments of jointed components, determination of inspection frequencies, fatigue life assessments of formed components, development of new models for the fatigue life estimation.