Crack growth rate prediction based on damage accumulation functions for creep-fatigue interaction

Andrey Tumanov Andrey Tumanov,A.p Zakharov A.P Zakharov,V.n Shlyannikov V.N Shlyannikov

doi:10.3221/igf-esis.52.23

Andrey Tumanov Andrey Tumanov, A.p Zakharov A.P Zakharov + Show 1 more

Open Access

https://doi.org/10.3221/igf-esis.52.23

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Abstract

The present study is concerned with formulation of a model for the creep–fatigue crack growth rate prediction on the base of fracture damage zone concepts. It is supposed that crack growth rate can be determined by integration of damage accumulation rate equations into the fracture process zone for low-cycle fatigue and creep loading independently. In the case of low-cycle fatigue loading the damage accumulation function proposed by Ye and Wang was used as well as a classical Kachanov-Rabotnov power law was employment for the creep damage accumulation characterization. Fracture process zone size is calculated on the base of the nonlinear stress intensity factors concept proposed by Shlyannikov. The background for the proposed general model of crack growth rate under creep and fatigue interaction is given in order to comparison with the experimental data. Experimental study of crack growth rate under creep and fatigue interaction is performed for compact tension specimen made from 20CrMoV5. Crack growth rate carried out at the elevated temperature of 550°C according to ASTM E2760 standard. The predictions of the crack growth rate were compared with the experimental data for the 20CrMoV5 steel obtained at an elevated temperature, and the agreement was found to be satisfactory.

Highlights

S tructures in the aviation, space flight, power generation, and petrochemical industries are typically exposed to elevated temperatures
It is well known that the creep damage accumulation from the damage caused by cyclic loading is different
The Lemaitre model [2] is the one of the most frequently used for the fatigue damage accumulation behavior

Summary

Introduction

S tructures in the aviation, space flight, power generation, and petrochemical industries are typically exposed to elevated temperatures. Creep-fatigue interaction; Crack growth rate prediction; Nonlinear stress intensity factors. For the different creep and fatigue laws if the stress state is unchanged the scalar, vector, and tensor damage parameters give almost identical results.

Results

Conclusion