Statistical Model of Roughness Induced Crack Closure

Statistical Model of Roughness Induced Crack Closure

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A new model is proposed enabling to assess the influence of structure coarseness on roughness induced crack closure in the fatigue threshold region. It takes the plastic zone size effect into account in terms of the grain size statistical distribution. In this approach, only grains larger then the cyclic plastic zone size are assumed to contribute to the roughness induced crack closure. The validity of this model was verified by a very good reproduction of experimental dependencies of the threshold stress intensity factor ∆Kth on the mean grain size obtained on the ARMCO iron specimens. In this analysis, two fitting parameters with clear physical meaning get expected and reasonable values.

A new model is proposed enabling to assess the influence of structure coarseness on roughness induced crack closure in the fatigue threshold region. It takes the plastic zone size effect into account in terms of the grain size statistical distribution. In this approach, only grains larger then the cyclic plastic zone size are assumed to contribute to the roughness induced crack closure. The validity of this model was verified by a very good reproduction of experimental dependencies of the threshold stress intensity factor ∆Kth on the mean grain size obtained on the ARMCO iron specimens. In this analysis, two fitting parameters with clear physical meaning get expected and reasonable values.

roughness, crack closure, fatigue, plastic zone s, threshold stress intensity factor, ARMCO iron

roughness, crack closure, fatigue, plastic zone s, threshold stress intensity factor, ARMCO iron

POKLUDA, J., ŠANDERA, P., HORNÍKOVÁ, J.

01.01.2000

Elsevier

San Sebastian

Fracture Mechanics: Applications and Challenges, ECF 13

CD