thermo-mechanical fatigue life prediction for exhaust manifold based on sehitoglu model considering oxidation and creeping damages

The exhaust manifolds are subjected to higher thermal stress than before, due to the increasing engine power output, fuel consumption, and gas emission. thus, simulation and analysis of fatigue cracks are essential. in this paper, thermo-mechanical fatigue (tmf) life analysis of the exhaust manifold is performed by using finite element method (fem) and abaqus software to predict the temperature and stresses and then tmf fatigue life by using sehitoglu theory and femfat software. mechanical properties of high silicon molybdenum (hisimo) ductile cast irons (dci) obtained by lcf and tensile tests at different temperatures. the results of finite element analysis (fea) showed that the maximum temperature and stress values in the exhaust manifold are 757.4 °c and 321.8 mpa and the position is at the confluence region. the numerical results showed that the area where the maximum temperature and stress occur is where the least tmf life is estimated. the obtained tmf results proved that mechanical damage plays a leading role in the total tmf life of the exhaust manifold. the oxidation damage was greater than the creep damage which is not negligible.

thermo-mechanical fatigue life prediction for exhaust manifold based on sehitoglu model considering oxidation and creeping damages

the exhaust manifolds are subjected to higher thermal stress than before, due to the increasing engine power output, fuel consumption, and gas emission. thus, simulation and analysis of fatigue cracks are essential. in this paper, thermo-mechanical fatigue (tmf) life analysis of the exhaust manifold is performed by using finite element method (fem) and abaqus software to predict the temperature and stresses and then tmf fatigue life by using sehitoglu theory and femfat software. mechanical properties of high silicon molybdenum (hisimo) ductile cast irons (dci) obtained by lcf and tensile tests at different temperatures. the results of finite element analysis (fea) showed that the maximum temperature and stress values in the exhaust manifold are 757.4 °c and 321.8 mpa and the position is at the confluence region. the numerical results showed that the area where the maximum temperature and stress occur is where the least tmf life is estimated. the obtained tmf results proved that mechanical damage plays a leading role in the total tmf life of the exhaust manifold. the oxidation damage was greater than the creep damage which is not negligible.