Date of Award


Degree Name

Master of Science in Engineering


Mechanical and Aerospace Engineering

First Advisor

Dr. Daniel Kujawski

Second Advisor

Dr. Muralidhar Ghantasala

Third Advisor

Dr. Jinseok Kim


Fatigue damage, surface roughness, hysteresis, strain-hardening, micro-hardness

Access Setting

Masters Thesis-Open Access


Fatigue is an essential consideration in the design of high performance, safety-critical structures, and components, as fatigue failure constitutes more than 70% of failures in dynamically loaded components. This research aims to shed light on the effect of surface roughness on the micro-hardness in metals through experimental techniques (Part 1), the correlation between the traditional fatigue testing and instrumented cyclic micro-hardness testing to determine the material properties modeled by Ramberg - Osgood relationship(Part 2), and the effect of the fatigue damage on micro-hardness and surface roughness (Part 3).

For this research, Al 7075 - T651 and Al 6061 - T651 chosen as the materials due to their vast range of applications in the aerospace industry for the fuselage, wings of airplanes, and in the automotive industry for engine radiators, wheels, body parts of the automobiles. Depending on the data acquired from all the experiments, the fatigue damage characterization can be evaluated using the surface roughness and the instrumented micro-hardness indentation measurements, which are aimed to predict the remaining life of components while at service.