Statistical Approach to Roughness-Induced Shielding Effects

Statistical Approach to Roughness-Induced Shielding Effects

Peer-reviewed article not indexed in WoS or Scopus

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 enablesthe determination of the intrinsic valuesof 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 shileding 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.

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 enablesthe determination of the intrinsic valuesof 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 shileding 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.

crack branching; crack closure; roughness-induced shielding; size ratio; statistical approach

crack branching; crack closure; roughness-induced shielding; size ratio; statistical approach

POKLUDA, J. ŠANDERA, P. HORNÍKOVÁ, J.

01.03.2004

'Neuveden'

'Neuveden'

8756-758X

FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES

27

2

United Kingdom of Great Britain and Northern Ireland

141

17