2026-09-22T16:10:18Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/87966 2023-07-11 col_2142_5131 col_2142_14800 com_2142_5130 com_2142_14799 com_2142_234

The student, Ariel Wilhelmsen, accepted the attached license on 2015-06-17 at 11:38. The student, Ariel Wilhelmsen, submitted this Thesis for approval on 2015-06-17 at 11:46. This Thesis was approved for publication on 2015-06-18 at 09:36. DSpace SAF Submission Ingestion Package generated from Vireo submission #8286 on 2015-09-29 at 13:21:31 text Made available in DSpace on 2015-09-29T20:37:44Z (GMT). No. of bitstreams: 2 WILHELMSEN-THESIS-2015.pdf: 3240252 bytes, checksum: 9f5e190641a91c76e2fbc69ed44b86ec (MD5) LICENSE.txt: 4213 bytes, checksum: f401801d1966288357e0d6ce6244b0ba (MD5) Previous issue date: 2015-06-18 application/pdf http://hdl.handle.net/2142/87966 en Copyright 2015 Ariel Wilhelmsen Digital Image Correlation (DIC) Carbon Fiber Composites Transverse Tension Cross-ply Composite Laminates Characterization of local strain fields in cross-ply composites under transverse loading Sottos, Nancy R. Wilhelmsen, Ariel 2015-09-29T20:37:44Z 2015-09-29T20:37:44Z 2015-08 2015-06-18 Transverse matrix cracks often occur in fiber-reinforced cross-ply polymer matrix composites subjected to tensile loads. Experimental visualizations of strain fields are necessary to calibrate and validate computational models that predict strain development and transverse crack initiation. In this study, fluorescent digital image correlation (DIC) measurements are used to study the evolution of highly localized displacements and strains under transverse tension. Composite coupons and Aluminum 6061-T6 control samples, both with dimensions of 50 mm in length, 2 mm in width, and 1.25 mm in height, were prepared with one polished surface spincast with a solution of fluorescent nanoparticles to produce a DIC speckle pattern. Specimens were tested in a miniature load frame in an optical microscope. Using a long working distance objective lens and a monochrome camera with a 668.4 by 534.7 μm resolution, fluorescent images of the polished surface were captured periodically to track the developing strains in the specimen. Strains were successfully measured using DIC for composite specimens. Bands of strain were observed to form perpendicular to 0° plies and often traced along pockets of resin. Additionally, strain concentrations formed between tow borders and pockets of resin and were nearly twice the value of the average strain for the area of interest. These results were consistent qualitatively with a photoelastic study shown in literature. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2015-09-29 without embargo terms text 2015-8 Aerospace Engineering Aerospace Engineering University of Illinois at Urbana-Champaign Thesis M.S.