2026-09-21T02:05:51Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/129282 2025-10-20 col_2142_5131 col_2142_14787 com_2142_5130 com_2142_9630 com_2142_234

application/pdf en text Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo terms The student, Yuvam Kulkarni, accepted the attached license on 2025-04-30 at 08:24. The student, Yuvam Kulkarni, submitted this Thesis for approval on 2025-04-30 at 08:25. This Thesis was approved for publication on 2025-05-05 at 15:02. DSpace SAF Submission Ingestion Package generated from Vireo submission #22092 on 2025-10-19 at 18:11:18 Development and validation of full-field indentation microscopy (FIM) for anisotropic materials Kulkarni, Yuvam 2025-05-05 Luetkemeyer, Callan M Inverse methods soft-material mechanical characterization full-field methods finite element analysis indentation virtual fields method eng Indentation offers several advantages over other mechanical testing methods, such as being non-destructive, capable of probing individual layers or thin films, and enabling localized measurements in heterogeneous materials. However, current indentation methods have limitations when characterizing soft polymers and tissues. The unimodal force-displacement data collected by gold-standard techniques like atomic force microscopy offer little information about material nonlinearity and no information about material anisotropy. This work presents the development and validation of Full-Field Indentation Microscopy (FIM), a new material characterization framework that overcomes the limitations of traditional indentation methods. Experimentally, FIM uses the weight of a glass microsphere to deform a soft material and a confocal microscope to take 3D images before and after indentation; the images are then used to estimate displacement fields. The inverse modeling framework for FIM, developed here, is based on the virtual fields method (VFM), a full-field inverse method, which can leverage the heterogeneous deformation inherent to indentation to extract nonlinear and anisotropic material parameters from a single indentation test. Specifically, this initial work aims to develop and validate the inverse analysis for FIM for anisotropic linear elastic materials. The objectives are (1) to identify efficient virtual fields to accurately estimate linear elastic-anisotropic material properties via FIM, (2) examine the feasibility of identifying nonlinear isotropic and nonlinear anisotropic material properties and (3) to investigate the domain size (i.e., field-of-view) required for experiments. 2025-05 Thesis https://hdl.handle.net/2142/129282 Copyright 2025 Yuvam Kulkarni Mechanical Sci & Engineering Mechanical Engineering University of Illinois Urbana-Champaign M.S. Thesis