Development of a tool for bench to vehicle damage model calculation: application on a real case

The behaviour of many components subjected to combined thermal and mechanical fatigue loads has great importance in mechanical industry, in particular in the field of vehicles. The damage cumulated by the components as a result of this type of load is estimated through some damage models and their validation is carried out by accelerated fatigue tests that produce the same cumulative damage that would occur in their lifetime in order to reduce time and cost. In this thesis project a calculation tool, by the means of the software AVL CONCERTO, was created for the optimization of the analysis of engine maps measured on the test bench and mission time history profile data recorded in field and the implementation of the damage models just mentioned. Thanks to a simplified interface and the immediate availability of graphic and numerical outputs, this tool allows to significantly reduce the time of calculation and the possibility of mistakes due to manual calculation process. The second part of the study involved the validation of the investigated models and then the fatigue analysis of a water-to-air heat exchanger (WCAC) that had suffered several breakages during its use of which it was necessary to identify the causes of breakage. This led to the formulation of a damage model based on the inlet air temperature of the WCAC, that was subsequently used to estimate the hours at breakage of a second water-to-air heat exchanger and to hypothesize new tests on it, useful for the purposes of validation.