Modelling and design of an exhaust manifold under thermomechanical loading

• Published in: Proceedings of the Institution of Mechanical Engineers. Part D, Journal of automobile engineering Journal of automobile engineering, 2006-12, Vol.220 (12), p.1755-1764
• Main Authors: Park, K H, Choi, B L, Lee, K W, Kim, K S, Earmme, Y Y
• Format: Article
• Language: English
• Subjects: Applied sciences; Engines; Engines and turbines; Exact sciences and technology; Fatigue life; Finite element analysis; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Internal combustion engines: gazoline engine, diesel engines, etc; Mechanical engineering; Mechanical engineering. Machine design; Physics; Solid mechanics; Structural and continuum mechanics; Thermal cycling
• ISSN: 0954-4070; 2041-2991
• DOI: 10.1243/09544070D06404

Abstract In the early stage of designing an exhaust manifold, a designer usually has to perform the fatigue analysis of each candidate of the exhaust manifold, and to decide whether or not it is satisfactory. In each case, elastoplastic stress analysis by the finite element method (FEM) is required, which is very time consuming considering the preprocessing and postprocessing of the FEM data. In this study, a thermal stress index is proposed for a practical application to the early stage of designing the exhaust manifold. Although this index (the ratio of the elastic effective stress to the yield stress) does not predict quantitatively the expected fatigue life, it is believed that it can be easily evaluated, and its merit lies in the quick estimation of the effect of the design parameters at the development stage without performing complete non-linear analysis of fatigue.