Electrodynamic axial-torsional fatigue testing system

• Subject Area: Materials Engineering
• Term: Funded in 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 543857918

In the context of the reliable use of implants and the damage-tolerant design of fiber-reinforced composites, innovative steels and light metals, application-oriented testing is a necessary prerequisite. A detailed elucidation of the deformation and damage mechanisms occurring in the material under multi-axial loading, combined with temperature and/or corrosion impact, requires the development of new testing methods and damage models. The axial-torsional fatigue testing system significantly strengthens the profile area "From elementary particles to products along value added networks" at TU Dortmund University. In the field of permanent and bioresorbable implants with tailored functionality, patients‘ safety is fundamental for responsible use. Typical application examples, such as bone screws and spinal implants, are loaded by complex multi-axial stresses during use, mostly superimposed by corrosive impacts based on body fluids. The application-oriented characterization of fatigue properties under these conditions, particularly in terms of the requirements regarding contamination-free testing, results in a wide range of demands, which, in conjunction with the existing equipment, are fulfilled in an outstanding manner by the requested system. In the context of fiber- reinforced composites, the material behavior under multi-axial loading has been partially investigated to date. The requested axial-torsional fatigue testing system therefore extends the testing possibilities with regard to the detection of unknown damage mechanisms at low temperature as well as elevated temperature. In addition, optical monitoring is possible during fatigue testing. Especially for steels and light metals, crack paths and the crack propagation behavior depending on defect distribution and microstructure can be transferred into universal, microstructure- and defect-based damage models in a wide range of applications. Cyclic testing at different temperatures and proportions of superimposed axial and torsional loading, in terms of current research in the field of process- and deformation-induced damage evolution, will enable a separation of the fundamental mechanisms, both in the low cycle fatigue and high cycle fatigue regimes, and thus provide a broad understanding of the deformation and damage processes and their effects on material and component behavior. The gained knowledge will subsequently be applied for validation and transfer to other multi-axial loading conditions to generate material models including materials, microstructure, environment and loading in terms of application-oriented design of the process-structure-property relationship.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Elektrodynamisches Axial-Torsional-Schwingprüfsystem
• Instrumentation Group: 2910 Dynamische Prüfmaschinen und -anlagen, Pulser
• Applicant Institution: Technische Universität Dortmund
• Leader: Professor Dr.-Ing. Frank Walther