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This study focuses on the Termomechanical Fatigue (TMF) analysis for an exhaust manifold. Bolt tension and temperature field has been applied in order to get variation on stresses, going from room load condition to a full load condition. The temperature field has been acquired from 1D simulation and adjusted to fit experimental values measured on the vehicle. Low cycle fatigue (LCF) has been considered to evaluate the exhaust manifold under the stress cycles produced by temperature fluctuation. Thermal and stress analysis have been performed by Abaqus package. An in-house code has been employed in the fatigue analysis. The bolt torque and the temperature field on the engine and exhaust manifold are the loads considered in the analysis.

Approximated analytical methods for evaluation notch stress and strain under multiaxial loading are considered. Results from analytical methods are compared to results from elastic-plastic finite element analysis. An engine bearing cap is evaluated under both methods, considering the services load from the combustion pressure and also the bolt tension. Linear kinematic hardening rule and Mises plasticity model have been considered. Results from analytical models and nonlinear finite element analysis are compared.

This paper presents the methodology for structural analysis of a high-speed Diesel engine aluminum cylinder head for Pick-up application, considering the finite element method. As boundary conditions, it was considered the loads from the bolts tightening process, combustion peak pressure, and thermal loading. The stresses generated during the assembly of the valve seats and valve guides were also evaluated. The valve train dynamic loads were not analyzed or considered in this paper, due to its negligible effects at the critical regions. The FE model contains the upper part of the crankcase and the entire cylinder head. Heat transfer coefficients at the water jackets were obtained from a CFD calculation and used at the heat transfer analysis to evaluate the thermal stresses. The residual stresses generated by the casting and manufacturing processes, as well the heat treatments for the alloy mechanical properties improvements, are also considered on this analysis.