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Statistical approach to roughness‐induced shielding effects
Author(s) -
POKLUDA J.,
ŠANDERA P.,
HORNÍKOVÁ J.
Publication year - 2004
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2004.00734.x
Subject(s) - materials science , fracture toughness , surface finish , electromagnetic shielding , plasticity , crack closure , shielding effect , surface roughness , fracture mechanics , composite material , mechanics , forensic engineering , structural engineering , engineering , physics
A new theoretical concept is introduced to describe the roughness‐induced shielding effects in metallic materials. This approach is based on the statistics of the local ratio between the characteristic microstuctural distance and the plastic zone size. A general equation involving both the crack branching and the crack closure phenomena is derived in the frame of linear elastic fracture mechanics under the assumption of remote mode I loading. It enables the determination of the intrinsic values of both the fracture toughness and the fatigue crack growth threshold. Moreover, the roughness‐induced component can be separated from other closure components, such as the plasticity or oxide‐induced closure. In order to estimate the total roughness‐induced shielding effect only standard materials data such as the yield stress, the mean grain size, the surface roughness and the fracture mode are necessary. Examples of applications concerning static fracture and fatigue are presented for selected metallic materials.