Aerospace series. Test methods for metallic materials. Determination of fatigue crack growth rates using corner-cracked (CC) test pieces

2011 ◽  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Test Methods ◽  
Metallic Materials ◽  
Test Pieces ◽  
Crack Growth Rates

Fatigue Crack Growth in Flow Formed INCONEL 718

2016 ◽  
Vol 879 ◽  
pp. 374-379
Author(s):  
Costa Coleman ◽  
Martin R. Bache ◽  
Carl Boettcher
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Growth Rates ◽  
Inconel 718 ◽  
Longitudinal Direction ◽  
Test Pieces ◽  
Crack Growth Rates

Fatigue crack propagation has been measured in flow formed Inconel 718 (IN718). Test pieces were extracted from a flow formed tubular structure in the longitudinal direction, retaining the tube curvature across their width. Crack growth rates (da/dN) were measured at 20, 300, and 400oC. For comparison, tests were repeated on specimens with an identical geometry but machined from conventionally forged IN718. Detailed metallurgy of the flow formed material is presented.

scholarly journals Advantageous Description of Short Fatigue Crack Growth Rates in Austenitic Stainless Steels with Distinct Properties

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 475
Author(s):  
Lukáš Trávníček ◽  
Ivo Kuběna ◽  
Veronika Mazánová ◽  
Tomáš Vojtek ◽  
Jaroslav Polák ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Growth Rates ◽  
Large Scale ◽  
J Integral ◽  
Scale Yielding ◽  
Residual Fatigue ◽  
Crack Growth Rates

In this work two approaches to the description of short fatigue crack growth rate under large-scale yielding condition were comprehensively tested: (i) plastic component of the J-integral and (ii) Polák model of crack propagation. The ability to predict residual fatigue life of bodies with short initial cracks was studied for stainless steels Sanicro 25 and 304L. Despite their coarse microstructure and very different cyclic stress–strain response, the employed continuum mechanics models were found to give satisfactory results. Finite element modeling was used to determine the J-integrals and to simulate the evolution of crack front shapes, which corresponded to the real cracks observed on the fracture surfaces of the specimens. Residual fatigue lives estimated by these models were in good agreement with the number of cycles to failure of individual test specimens strained at various total strain amplitudes. Moreover, the crack growth rates of both investigated materials fell onto the same curve that was previously obtained for other steels with different properties. Such a “master curve” was achieved using the plastic part of J-integral and it has the potential of being an advantageous tool to model the fatigue crack propagation under large-scale yielding regime without a need of any additional experimental data.

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