Thermo-mechanical analysis for exhaust manifold using elasto-viscoplastic chaboche model

The confluence area cracks are one of the most important durability problems in internal combustion engines. The aim of this article is to present thermo-mechanical analysis for exhaust manifold using elastoviscoplastic Chaboche model. The Chaboche model was selected for the elasto-viscoplastic model including a kinematic hardening plastic law coupled with the Norton creep equation. The modeling, meshing and analyzing were performed on a finite element model of the exhaust manifold in ABAQUS software. In order to increase the accuracy of finite element analysis (FEA) results, temperature-dependence of material parameters was considered. The results of mechanical-thermal analysis showed that the maximum temperature and stress are visible in the confluence area. Obtained FEA results proved the manifold gasket leak is another critical region that has to sustain the expanding and contracting of the heated exhaust manifold metal. The results of the modal analysis proved that the maximum strain energy density and total strain energy exist in the confluence area. The results of the thermomechanical analysis are compared with the real sample of the damaged exhaust manifold to evaluate the properly results, and it has been shown that serious identified zones correspond to the failure areas of the real sample.