SUBJECT: Ph.D. Proposal Presentation
BY: Dipen Patel
TIME: Wednesday, November 11, 2015, 3:30 p.m.
PLACE: Love Building, 109
TITLE: Extraction of elastic-plastic properties from polycrystalline sample using spherical nanoindentation measurements and finite element simulations
COMMITTEE: Dr. Surya Kalidindi, Chair (ME)
Dr. David McDowell (ME)
Dr. Hamid Garmestani (MSE)
Dr. Antonia Antoniou (ME)
Dr. Richard Neu (ME)


Simulating complex interactions between microscale constituents of a composite material system is essential to understanding and predicting overall performance characteristics. Such models, however, need reliable information on the properties of the individual microscale constituents. In this work, I propose to develop new protocols for estimating the properties of the constituents from the indentation stress-strain curves measured using spherical tip. More specifically, I will extract the grain-scale elastic-plastic parameters (e.g., single crystal elastic stiffness constants, initial slip resistances, and slip hardening rates) from the instrumented spherical indentation measurements on multiple grains in polycrystalline samples using a two-step process. In the first stage of this work, I will develop a finite element model of spherical indentation to establish the functional dependence of the grain-scale parameter(s) on the indentation stress-strain curve. In the second stage, I will formulate protocols to estimate the grain-scale parameter(s) that produce the best fit of the measurements to the function established in the first step. The viability of the approach will be demonstrated on a range of materials, including an as-cast polycrystalline samples as well as irradiated materials.