Development of methods for fatigue life prediction of combustors made of alloys and ceramic matrix composites (Masterarbeit)

Abstract

The pre-design stage of an aircraft engine requires an overview of the main engine performance and structural properties, to enable rapid decision making on a concept. For combustion chambers, different types of analyses are used to determine the viability of a concept, e. g. finite element analysis, modal analysis, etc. Among them, fatigue analysis is a key topic due to the high stresses and particular temperature conditions within the combustion chambers. Due to the many material properties to be taken into account for fatigue analysis, extensive theories and formulas are available in the literature, making it difficult to choose an estimation method. This master thesis presents the realization of an internal tool existing at DLR, coded in Python, concerning the design of a fatigue life prediction method for an aircraft combustion chamber, in metal alloys or ceramic matrix composites. After the finite element and modal analysis already existing in the code, fatigue material properties from the literature are used, included in the Python tool, and extrapolated to have as an output a number of cycles to failure of the combustor, for different engine load points (take-off, taxi, cruise, idle, top of climb).