via 

BlueJeans Video Conferencing 

https://bluejeans.com/396605134

will be held the

DISSERTATION DEFENSE

for

Adrienne Muth

"A Large Scale Computational Study of Fatigue Hot-spots"

Committee Members: 

Prof. David McDowell Advisor, ME/MSE

Prof. Surya Kalidindi ME/MSE/CSE

Prof. Richard Neu ME/MSE

Reji John, Ph.D., AF Research Lab, Materials and Manufacturing Directorate

Adam Pilchak, Ph.D., AF Research Lab, Materials and Manufacturing Directorate

Abstract: 

Formation of a fatigue crack at the subgrain scale is a statistically rare event, as plastic deformation at the microscale ranges from highly heterogeneous at low strain to homogeneous at high strain. Fatigue Indicator Parameters (FIPs) for Ti-6Al-4V are computed using crystal plasticity finite element modeling of uniaxial cyclic straining of ensembles of statistical volume elements for a range of distinct microstructures at several strain amplitudes and mean strain conditions.  The selection of FIPs is informed by prior experimental studies. The sites of extreme value (EV) FIPs that are most likely to form and grow a fatigue crack are identified in these simulations, and 2-point spatial correlations are applied to investigate the higher dimensional influence of microstructure attributes in the neighborhood of these fatigue hot-spots. To reduce the high dimensionality of the associated 2-point correlations, principal component analysis is applied.  A reduced-order model using an artificial neural network is used to classify EV FIP locations based on these neighborhood spatial correlations.