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Cyclic near-tip fields for fatigue cracks along metal-metal and metal-ceramic interfaces

Journal Article · · Acta Metallurgica et Materialia; (United States)
; ;  [1]
  1. Brown Univ., Providence, RI (United States). Division of Engineering

Finite element analyses were conducted with the objective of determining the cyclic near-tip fields ahead of a stationary tensile fatigue crack lying along the interface between two dissimilar solids. The model systems analyzed are (1) a metal-metal bimaterial whose components have the same elastic properties but different plastic deformation characteristics, and (2) a metal-ceramic bimaterial. In both cases, monotonic loading to the peak tensile load results in a predominantly mode I field ahead of the crack. However, unloading in one or both components of the bimaterial with prior plastic deformation generates mixed-mode conditions at the crack tip. The mode mixity persists during a significant portion of the next loading phase and is gradually removed upon reloading to the peak stress. The cyclic plastic zone size directly ahead of the fatigue crack is approximately one-fifth the size of the monotonic plastic zone. The residual compressive stresses within the cyclic plastic zone are computed. The implication of reversed yielding and mixed-mode near-tip fields to constant-amplitude and variable-amplitude fatigue fracture are discussed.

DOE Contract Number:
FG02-84ER45167
OSTI ID:
6269571
Journal Information:
Acta Metallurgica et Materialia; (United States), Journal Name: Acta Metallurgica et Materialia; (United States) Vol. 41:8; ISSN 0956-7151; ISSN AMATEB
Country of Publication:
United States
Language:
English