Abstracts Category : Other

EXTRACTION OF ELASTIC-PLASTIC MATERIAL PROPERTIES FROM SPHERICAL INDENTATION STRESS-STRAIN MEASUREMENTS AND FINITE ELEMENT SIMULATIONS

by Dipen Patel

Simulating complex interactions at different length scales of a hierarchical material system is essential to multi-scale modelling techniques. Such models, however, need reliable information on the effective properties measured at different length scales (i.e., spanning from the macroscale to the microscale constituents). This dissertation presents new protocols for estimating these multiscale properties from the indentation stress-strain curves measured using recently developed spherical indentation protocols. More specifically, protocols are developed to extract the homogenized (bulk) properties (e.g., uniaxial yield strength and hardening rate) at the macroscale. At the microscale, new protocols are formulated to extract single crystal elastic-plastic parameters (e.g., elastic stiffness constants and initial slip resistance) from nanoindentation measurements. All of the new protocols will be validated using a finite element model of the spherical indentation, used here as a surrogate for the actual experiment. The protocols are also demonstrated on a range of materials, for which experimental measurements have been published in prior literature.Advisors/Committee Members: Kalidindi, Dr. Surya R (advisor), McDowell, Dr. David L (committee member), Garmestani, Dr. Hamid (committee member), Neu, Dr. Richard W (committee member), Antoniou, Dr. Antonia (committee member).