CAREER: Modeling Materials Across the Length Scales to Achieve Enhanced Thermomechanical Properties

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

This Faculty Early Career Development (CAREER) Program grant will focus on the formulation of efficient models and numerical schemes for understanding the length-dependent thermomechanical response of materials with rich microstructures. While extensive research has been conducted on the impact of characteristic microstructural length scales on thermal and mechanical properties of materials, little is known about the effect that length scale could have on the combined thermomechanical response. This research effort will provide modeling and computational capabilities for the analysis of next-generation materials with improved thermomechanical performance as needed for the most demanding engineering applications, including but not limited to, thermal barrier coatings for energy generation and propulsion, wear protection systems, and packaging of microelectronic devices. The educational component of this project will focus on promoting interest in STEM careers among Latino K-12 students through the development and implementation of a summer camp introducing participants to engineering and mechanics. The camp will adopt an interactive learning approach through the use of a simulation-based educational game for mobile platforms developed by the PI, and allow the realization of structures by 3D printing. The effectiveness of this educational approach will be evaluated, and the curriculum developed for the camp will be widely disseminated. The objective of the research is to elucidate the connections between microstructural length scales and material inherent length scales in relation to the thermomechanical response of engineering materials. The model consists of (i) a sub-micron scale model for the thermal conductivity based on the Boltzmann transport equation under the relaxation time approximation, (ii) a Fourier heat transport model at the mesoscale, (iii) a continuum model of mechanical deformation that explicitly resolves the microscopic geometric features of the material, and (iv) a cohesive model that accounts for the nucleation and propagation of quasistatic and dynamic cracks in the material. The model will then be utilized to study the following fundamental questions: How does grain size and grain size distribution affect the nucleation of thermal cracks for the steady state and dynamic thermomechanical problem? In the latter case, how is the nucleation of thermal cracks affected by applied temperature rates and length scale? What is the effect of length-scale and thermal cracks on macroscopic material strength, thermal conductivity, and thermal expansion? How does grading of the characteristic length scale of the material affect thermal conductivity and crack nucleation? This project will enable the PI to perform sustained research in this new area, creating the basis for a long-term career success.