The purpose of the research is to apply the modified Hartman-Schijve equation for predicting small crack growth rate in an additive manufactured titanium Ti-6Al-4V. Material constants in the equation were determined by long crack test data, and the threshold value of the stress intensity factor range was set to a small value. A small fatigue crack test was conducted to validate the fitted equation. Predicted fatigue life of another specimen configuration under bending load agreed well with the test result. The work shows that it may be possible to represent both small and long crack growth rates by the modified Hartman-Schijve equation with its material constants being determined by long crack test.

M. Shamir, X. Zhang, and A. K. Syed, “Characterising and representing small crack growth in an additive manufactured titanium alloy,” Engineering Fracture Mechanics, vol. 253, Aug. 2021

doi:10.1016/j.engfracmech.2021.107876.