Date of Award
Master of Science in Engineering
Mechanical and Aerospace Engineering
Mechanical and Aeronautical Engineering
Dr. Daniel Kujawski
Dr. Judah Ari-Gur
Dr. Philip Guichelaar
Masters Thesis-Open Access
A theoretical crack growth study on powder metallurgy aluminum alloys AA5091 and AA8022 was conducted. Specifically, the research focused on the crack growth retardation due to the application of a tensile overload. The tensile overload creates a plastic zone ahead of the propagating crack tip that induces the compressive residual stress after unloading. Such compressive residual stress pushes the crack tip faces against each other, which results in crack growth retardation.
In the study, simulation started from the calculation of the compressive residual stress. The details of the calculation steps are explained in the thesis. Eventually, the stress intensity factor range at the crack tip (∆Ktip) and the maximum stress intensity factor as the crack tip (Kmax tip) were calculated. These two parameters, along with constants C, m, and p, were used to simulate the crack growth rate.
Within the scope of the two-parameter (∆K, Kmax) approach, seven different calculation methods were investigated. The crack growth rate from each method was compared against experimental results from open literature. Finally, the best method among seven was determined.
Tsutsui, Wataru, "Prediction of Fatigue Crack Growth Retardation due to a Tensile Overload Using Two-Parameter (∆K, Kmax) Approach" (2008). Masters Theses. 4734.