Prof. Timothy Truster
Department of Civil and Environmental Engineering
University of Tennessee, Knoxville

Framework for Process and Performance Modeling at High Temperatures using Crystal Plasticity and Interface Finite Element Methods

ABSTRACT: This talk presents some of my group's recent efforts in applying crystal plasticity and interface finite element methods to elucidate the microstructural mechanics acting at high temperatures during processing or service conditions. As techniques for in-situ characterization of materials continue to advance alongside rapidly expanding computing platforms, the challenge of elucidating material mechanisms through physics-based computational modeling can be surmounted through Integrated Computational Materials Engineering (ICME) approaches. Our first area of interest is the modeling of microstructure and texture evolution during alpha-beta processing of titanium alloy Ti6242S. While this alloy is an ideal aircraft material, traditional manufacturing generates large microtextured regions (MTR) that degrade its low temperature dwell fatigue crack resistance. Pursuing a unified theory relating strain path to MTR breakdown, we simulated the interaction and evolution of alpha particles within MTR using crystal plasticity to compare with measured texture changes during hot working compression. Our second area of interest is the creep behavior of Grade 91 ferritic/martensitic steel, particularly to extrapolate behavior from short-life/high-stress experiments to operating regimes. Our model explicitly represents competing dislocation and diffusional mechanisms in both the grain bulk and grain boundaries, predicting a mechanism shift at lower stresses that impacts the creep life, notch-sensitivity, and creep ductility of Grade 91. Additionally, I will summarize other recent efforts of my group to develop robust and efficient methods for interfacial modeling in composites.

BIOGRAPHY: Dr. Truster is an associate professor in the Department of Civil and Environmental Engineering at the University of Tennessee. He earned his PhD in Civil Engineering with a concentration in structures from the University of Illinois at Urbana-Champaign in 2013. His teaching interests include finite element modeling, nonlinear finite element methods, and structural analysis. Truster's current research interests include computational interface mechanics, process modeling of titanium alloys, creep modeling in natural and engineered materials, stabilized finite element methods, and high performance computing. He was the recipient of a National Science Foundation CAREER grant in 2018 on the topic “Predictive Fatigue Behavior of Structural Materials Through Computationally-Informed Textural and Microstructural Influences”