Dislokační model plasticky a drsnostně indukovaného zavírání trhliny

Dislocation-based model of plasticity and roughness-induced crack closure

článek v časopise ve Web of Science, Jimp

en

The paper presents a discrete dislocation model of contact shielding effects in the case of small-scale yielding under plane-strain conditions. The model is physically transparent and, unlike continuum-based models for plane stress, it enables us to directly assess the magnitude of both plasticity and roughness-induced components of crack closure. Moreover, it reflects an influence of microstructure on the roughness-induced term. The closure components can be simply extracted from experimentally measured values of the remote DK using standard data on mechanical properties and microstructure. Thus, the effective threshold DKeff,th can be obtained as nearly independent of microstructure coarseness and applied cyclic ratio as shown for several important engineering materials

The paper presents a discrete dislocation model of contact shielding effects in the case of small-scale yielding under plane-strain conditions. The model is physically transparent and, unlike continuum-based models for plane stress, it enables us to directly assess the magnitude of both plasticity and roughness-induced components of crack closure. Moreover, it reflects an influence of microstructure on the roughness-induced term. The closure components can be simply extracted from experimentally measured values of the remote DK using standard data on mechanical properties and microstructure. Thus, the effective threshold DKeff,th can be obtained as nearly independent of microstructure coarseness and applied cyclic ratio as shown for several important engineering materials.

The paper presents a discrete dislocation model of contact shielding effects in the case of small-scale yielding under plane-strain conditions. The model is physically transparent and, unlike continuum-based models for plane stress, it enables us to directly assess the magnitude of both plasticity and roughness-induced components of crack closure. Moreover, it reflects an influence of microstructure on the roughness-induced term. The closure components can be simply extracted from experimentally measured values of the remote DK using standard data on mechanical properties and microstructure. Thus, the effective threshold DKeff,th can be obtained as nearly independent of microstructure coarseness and applied cyclic ratio as shown for several important engineering materials

Crack-tip shielding, Discrete dislocations, Fatigue crack-growth, Effective threshold, Size ratio

Crack-tip shielding, Discrete dislocations, Fatigue crack-growth, Effective threshold, Size ratio

2013

15.01.2013

0142-1123

46

1

35–40

6