TMF: Laser Application for a Close-to-Reality Simulation of Thermo-Mechanical Fatigue Processes in Rocket Engines

Kurzfassung

The concept of a thermo-mechanical fatigue (TMF) - test bench is discussed in this paper. Motivation for the TMF tests are two-fold: to assess the life expectation of structures being exposed to extreme thermo-mechanical loads first on subcomponent or panel level, and to serve as validation experiment for life-prediction models. In Europe, the concept of TMF-panel testing has been first very successfully applied to rocket thrust chamber structures in the frame of the Ariane 5 Flight Recovery Programme in 2003 and 2004. These encouraging results have motivated the partners DLR Lampoldshausen and EADS Astrium to jointly investigate again the TMF-bench concept with special focus on meeting relevant requirements for future liquid propulsion needs. The following key elements of a TMF test bench are presented in the paper: • the TMF heating device – a diode Laser, which is available already at DLR Lampoldshausen, • the design of the panel housing, • a tentative design of the TMF panel. Furthermore, numerical analyses of this tentative TMF panel – such as a CFD analysis of the coolant flow in the core part of the TMF panel and a thermal as well as a structural Finite Element analysis of the sandwich part of the TMF panel during the hot run are shown.