Date of Award
9-15-2016
Document Type
Thesis
Degree Name
Master of Science in Materials Science
Department
Department of Aeronautics and Astronautics
First Advisor
Shankar Mall, PhD.
Abstract
This thesis presents the results of a study to quantify the effects of biaxial loading on fatigue crack behavior in both air and saltwater (3.5% NaCl) environments from pre-cracked notched circular hole in a 7075-T6 cruciform specimen using a fracture mechanics approach. With stress ratio of R = 0.5, the crack growth behavior was investigated under fatigue loading with 0.5, 0, -0.5, and -1 biaxial stress ratio lambda. The crack propagation was monitored using optical microscopy. Finite Element Analysis was performed using the different stress ranges and stress ratios with various crack sizes to compute of stress intensity factors (delta K) at the crack tips. It was observed from the study that negative biaxiality has a very pronounced effect on the crack growth rate. The crack propagates faster with negative biaxiality and also the saltwater environment accelerates the crack propagation due to corrosion.
AFIT Designator
AFIT-ENY-MS-16-S-051
DTIC Accession Number
AD1018249
Recommended Citation
Alghamdi, Khalid A., "Corrosion Fatigue Crack Growth Behavior At Notched Hole In 7075-T6 Under Different Biaxial Stress Ratios" (2016). Theses and Dissertations. 270.
https://scholar.afit.edu/etd/270