GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Tuesday, November 19, 2019

12:00 PM

in MRDC 4211

will be held the

DISSERTATION DEFENSE

for

Morris Satin

“Characterization and Modeling of Two Dimensional Crack Growth in Gas Turbine Materials”

Committee Members:

Prof. William S. Johnson, Advisor, MSE/ME

Prof. Richard Neu, Advisor, MSE/ME

Prof. Arun Gokhale, MSE

Prof. Olivier Pierron, ME

Prof. Christopher Muhlstein, MSE

Abstract:

Surface flaws are common in gas turbine components and undergo a complex process of fatigue crack growth under mechanical and thermal loading.  This project seeks to bring greater clarity and understanding to the transition process of surface flaws to through cracks by implementing a transition method, and developing the associated codes and equations to do so based on careful consideration of boundary conditions, experimental data and finite element simulations.  In addition the effect of thermomechanical fatigue in surface flaws in Inconel 718 is investigated.  Inconel 718 displays a high-temperature time-dependent intergranular fracture mode that is explored experimentally, characterized, and modeled in the MPYZ-TMF fatigue crack growth code.  New models using the latest findings are proposed to accurately predict the shape, location, and overall lifetime of various surface flaw geometries.