Numerical Lifetime Assessment of Engine Parts Submitted to Thermomechanical Fatigue, Application to Exhaust Manifold Design

Lederer, G.; Charkaluk, Éric; Verger, Laetitia; Constantinescu, Andréï

doi:10.4271/2000-01-0789

Cited by 30 publications

(22 citation statements)

References 2 publications

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“…More details of this crucial point of the design approach are presented by Lederer et al 13 After the thermal loading determination, a global approach to thermomechanical fatigue design can be divided into two steps: The material is a nodular graphite cast-iron with silicon and molybdenum additives.…”

Section: G L O B a L A P P R O A C H I N F A T I G U E P R O B L E M Smentioning

confidence: 99%

Fatigue design of structures under thermomechanical loadings

Charkaluk¹,

Bignonnet

Constantinescu

et al. 2002

Fatigue Fract Eng Mat Struct

108

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This paper presents a global approach to the design of structures that experience thermomechanical fatigue loading, which has been applied successfully in the case of cast-iron exhaust manifolds. After a presentation of the design context in the automotive industry, the important hypotheses and choices of this approach, based on a thermal 3D computation, an elastoviscoplastic constitutive law and the dissipated energy per cycle as a damage indicator associated with a failure criterion, are first pointed out. Two particular aspects are described in more detail: the viscoplastic constitutive models, which permit a finite element analysis of complex structures and the fatigue criterion based on the dissipated energy per cycle. The FEM results associated with this damage indicator permit the construction of a design curve independent of temperature; an agreement is observed between the predicted durability and the results of isothermal as well as non isothermal tests on specimens and thermomechanical fatigue tests on real components on an engine bench. These results show that thermomechanical fatigue design of complex structures can be performed in an industrial context

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Section: G L O B a L A P P R O A C H I N F A T I G U E P R O B L E M Smentioning

confidence: 99%

Fatigue design of structures under thermomechanical loadings

Charkaluk¹,

Bignonnet

Constantinescu

et al. 2002

Fatigue Fract Eng Mat Struct

108

View full text Add to dashboard Cite

show abstract

“…Thus, macroscopic models are widely represented for the description of the behaviour of aluminium alloys (Smith et al, 1999;Lederer et al, 2000;Nicouleau et al, 2002;Guillot et al 2002), cast-iron alloys Bastid, 1995) and even stainless steels (Bucher et al, 2006). Most of the time, it is a classical Norton law which is used to describe viscosity.…”

Section: Introductionmentioning

confidence: 99%

New flow rules in elasto-viscoplastic constitutive models for spheroidal graphite cast-iron

Szmytka

Rémy

Maïtournam

et al. 2010

International Journal of Plasticity

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“…It should be noted that the strain rate used in this study was much higher than that in service, as this LCF testing was aimed as an accelerated approach to evaluate the fatigue properties of materials for exhaust manifolds. However, the applied strain ranges were comparable with those in the real components based on experimental and modeling results . The LCF tests were continued until specimen separation, while the lifetime was defined as the cycle number where a 50% drop of the maximum tensile stress was reached.…”

Section: Methodsmentioning

confidence: 99%

Low Cycle Fatigue Behavior of Heat‐Resistant Austenitic Cast Steels at 950 °C

Zhao

Engler-Pinto

et al. 2018

steel research int.

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Exhaust manifolds are frequently subjected to severe thermal cycling due to startup and shutdown of automobile engines; consequently, high‐temperature fatigue is the predominant failure mode for these components. The research about the relationship between high‐temperature fatigue properties and as‐cast microstructure in austenitic cast steels, which are the most popular materials for exhaust manifolds, is limited. In this study, strain‐controlled low cycle fatigue tests are conducted at 950 °C on two lab‐cast and one commercial‐cast austenitic cast steels with different morphology of primary Nb(C,N). The results indicate that decreasing the lamellar spacing of primary Nb(C,N) is an effective way to increase the LCF lifetime at the high strain range, hence the “Chinese‐script” primary Nb(C,N) is a more desirable morphology. The combination of cracking and prior oxidation of the dispersed plate‐like and blocky primary Nb(C,N) can result in the reduction of LCF lifetime. The influence of the primary Nb(C,N) morphology on the LCF lifetime is negligible at a low strain range, hence lowering the secondary dendrite arm spacing (SDAS) to less than 30 μm significantly extends the LCF lifetime of austenitic cast steels. Additionally, the plastic strain energy density is an effective parameter to predict the LCF lifetime at 950 °C in austenitic cast steels.

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Numerical Lifetime Assessment of Engine Parts Submitted to Thermomechanical Fatigue, Application to Exhaust Manifold Design

Cited by 30 publications

References 2 publications

Fatigue design of structures under thermomechanical loadings

Fatigue design of structures under thermomechanical loadings

New flow rules in elasto-viscoplastic constitutive models for spheroidal graphite cast-iron

Low Cycle Fatigue Behavior of Heat‐Resistant Austenitic Cast Steels at 950 °C

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