A quantitatively accurate theory of stable crack growth in single phase ductile metal alloys under the influence of cyclic loading

Abstract

I would like to dedicate this dissertation to the people who encouraged me when I first made the decision to attend college, namely Bob Benda and family, and Jess Lorentzen and family. I would also like to dedicate this to Dan Palan, who first introduced me to materials engineering as a discipline, and without whom, I may never have started down this path.

Crack closure in friction stir weldment using non‐linear model for fatigue crack propagation

“…Huffman identified Δ K tot expressed by means of Equation as a Δ K eff in Equation . Then, the closure correction is introduced into the KE law by means of Equations and .…”

“…Then, the closure correction is introduced into the KE law by means of Equations and . where σ 0.05 is the stress value corresponding to ε = 0.05, on the true stress–strain curve shown in Figure , and σ 0 is the material yield strength while Δ K appl is the current Δ K obtained from the J ‐integral conversion by using of Equation . Based on these equations, the closure term, U cl , can be expressed as follows: In the previous literature, it has been experimentally shown the effect of the R ‐ratio in the near‐threshold regime and that Δ K th must be corrected to have an effective stress intensity range Δ K th,eff , able to fully consider the crack closure effect.…”

“…where σ 0.05 is the stress value corresponding to ε = 0.05, on the true stress-strain curve shown in Figure 1, 35 and σ 0 is the material yield strength while ΔK appl is the current ΔK obtained from the J-integral conversion by using of Equation (13). Based on these equations, the closure term, U cl , can be expressed as follows:…”