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Kersh, Mariana E. Muckatira, Sameer Kariappa 2019-02-06T19:36:44Z 2019-02-06T19:36:44Z 2018-12-12 2018-12 Micro-CT scanning of murine femurs before and after uniaxial compression produce 3-dimensional images detailing changes within the bone micro-architecture. Digital volume correlation (DVC) is a mathematical technique used to determine strain within the bone volume, by tracing the dislocation of a pattern between the 3-dimensional images. Uncertainty in the microstrain calculated arises due to limitations in microscopy, the absence of a homogeneously distributed pattern within the bone volume, and inconsistency the methodology used to process the micro-CT scans and microstrain data. The uncertainty in strain was quantified as strain error (SE), measured by analyzing repeated micro-CT scans of an uncompressed bone. The Minimum SE quantified was 180-225 microstrains in accuracy (mean), with a 1100-2100 microstrain precision (standard deviation) in rats; 10-150 microstrains in accuracy, with a 1100-1700microstrain precision in mice. SE displays a regular random distribution throughout the bone volume, centered about 0 and showing strain in both tension and compression. The minimum SE is obtained by optimizing the DVC input parameters using a design of experiments (D0E). A sub-volume size of 43-55 voxels with a 50-75% volume overlap between consecutive steps of the DVC yielded the lowest SE at the highest strain resolution within the bone sub-volume. A strain error resolution (SER) of 2500 microstrains encapsulates over 90% of the SE and is chosen as the minimum strain value that is viable when evaluating microstrain from a compression test of the bone. Any strain within the SER limits are eliminated from a viable set of microstrain value, believed to either be error or minimally contributing to the macroscopic properties of the bone. SER of 2500 microstrain results in a displacement uncertainty of 9-11 um within the bone subvolume. A visual inspection of the repeated scans shows an uncertainty of 2.5 voxels between the 2 images when imaged at a nominal resolution of 4-5 um. The use of monochromatic x-rays (such synchrotron x rays) can increase resolution and reduce the signal-to-noise ratio in the CT scanning process, thus reducing the SE calculated by DVC. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-02-05 without embargo terms The student, Sameer Muckatira, accepted the attached license on 2018-12-12 at 10:59. The student, Sameer Muckatira, submitted this Thesis for approval on 2018-12-12 at 11:10. This Thesis was approved for publication on 2018-12-12 at 16:23. DSpace SAF Submission Ingestion Package generated from Vireo submission #13301 on 2019-02-05 at 11:16:09 Made available in DSpace on 2019-02-06T19:36:44Z (GMT). No. of bitstreams: 2 MUCKATIRA-THESIS-2018.pdf: 20546786 bytes, checksum: be042cfbff52886bfa0e37a1c623fa5f (MD5) LICENSE.txt: 4213 bytes, checksum: 661215bc0b386cd282ad6b9678a4088b (MD5) Previous issue date: 2018-12-12 application/pdf http://hdl.handle.net/2142/102519 en Copyright 2018 Sameer Muckatira Digital Volume Correlation Microstrain Bone Biomechanics Volumetric Analysis CT Scanning Error estimation in whole bone microstrain measurement when using digital volume correlation text text Mechanical Sci & Engineering Mechanical Engineering University of Illinois at Urbana-Champaign Thesis M.S.