Techniques for Experimental Measurement of Fatigue Crack Closure

2007 ◽  
Vol 7-8 ◽  
pp. 3-9 ◽  
Author(s):  
David Nowell
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Crack Closure ◽  
Experimental Measurement ◽  
Moiré Interferometry ◽  
Experimental Results ◽  
Moire Interferometry ◽  
Fatigue Crack Closure ◽  
Closure Models ◽  
Important Phenomenon

Fatigue crack closure is an important phenomenon which needs to be taken into account in the development of models for crack propagation. This paper presents an overview of techniques for measuring crack closure. The moiré interferometry approach is described in more detail and some experimental results are presented and compared with the predictions of closure models.

Experimental results on fatigue crack closure for two aluminum alloys

1979 ◽  
Vol 12 (2) ◽  
pp. 231-240 ◽  
Author(s):  
Jose A. Vazquez ◽  
Augusto Morrone ◽  
Hugo Ernst
Keyword(s):  
Fatigue Crack ◽  
Aluminum Alloys ◽  
Crack Closure ◽  
Experimental Results ◽  
Fatigue Crack Closure

A comparative study of fatigue crack closure

1977 ◽  
Author(s):  
J. RUEPING ◽  
B. HILLBERRY ◽  
S. METTLER ◽  
W. STEVENSON
Keyword(s):  
Fatigue Crack ◽  
Comparative Study ◽  
Crack Closure ◽  
Fatigue Crack Closure

scholarly journals P-Texture Effect on the Fatigue Crack Propagation Resistance in an Al-Cu-Mg Alloy Bearing a Small Amount of Silver

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2481 ◽  
Author(s):  
Yangcheng Hu ◽  
Zhiyi Liu ◽  
Qi Zhao ◽  
Song Bai ◽  
Fei Liu
Keyword(s):  
Electron Microscopy ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Crack Closure ◽  
High Intensity ◽  
Damage Tolerance ◽  
Mg Alloy ◽  
Random Texture ◽  
Texture Effect

P-texture effect on the fatigue crack propagation (FCP) resistance in an Al-Cu-Mg alloy containing a small amount of Ag, is investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron back scattering diffraction (EBSD). Results shows that the high intensity P-texture sheet has lower σ0.2/σb, lower FCP rate and higher damage tolerance than random texture sheet. Fracture analysis indicates that the striations spacing of high intensity P-texture sheet is much smaller than that of random texture sheet and it has a rougher fatigue fracture surface, which causes a significant roughness induced crack closure (RICC) effect. The calculation results manifest that high intensity P-texture sheet possesses a higher crack closure level reaching 0.73 as compared to random texture sheet (only 0.25). The statistical analysis results reveal the P-grains have large twist angle of 105–170° and tilt angle of 5–60° with neighboring grains, which is similar to Goss-grains. This is the fundamental reason that P-texture sheet has the same FCP resistance and induces fatigue crack deflection as Goss-texture sheet. Additionally, the most {111} slipping planes of P-grains are distributed in the range of 30–50° deviating from transverse direction of the sheet. This results in more {111} slipping planes to participate in cyclic plastic deformation, which is beneficial to reduce fatigue damage accumulation and improve the damage tolerance of Al-Cu-Mg-Ag alloy.

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