2026-09-23T15:58:42Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/83801 2023-07-11 col_2142_5131 col_2142_14787 com_2142_5130 com_2142_9630 com_2142_234

Socie, Darrell F. Gao, Husheng 2015-09-25T21:12:10Z 2015-09-25T21:12:10Z 10000-01-01 2003 2003 Plasma-sprayed thick thermal barrier coatings (TTBCs) are being developed for thermal protection of diesel engine components in high temperature service. Comparing to thin thermal barrier coatings used in gas turbine industry, increased thickness causes some TTBCs failure to occur within the bulk of the coating materials and away from the interface. This necessitated the study of mechanical properties of the coating materials independent of the substrate. In order to enhance the performance and to predict the life of TTBCs, we have to understand the materials response under multiaxial stress states, the deformation mechanisms, failure criteria, and the constitutive relations. In this study, the deformation behavior, the deformation mechanisms, and the failure criteria were investigated. The results shows that under combined axial and shear loading, thin walled tubular specimens of ceramic coatings failed in one of two modes, a tensile failure perpendicular to the maximum principal stress when s1≥sTf or a shear failure through the thickness when s3≤sCf . Two apparatuses for in situ SEM torsion and compression testing were developed for deformation mechanisms investigation. The deformation mechanisms were identified as tensile microcracking, crack closing, and crack sliding. A model has been developed for the constitution relation of functionally graded TTBCs. It is shown that with a few simple experiments, this model can be used to predict the cyclic deformation behavior of the functionally graded TTBCs. Made available in DSpace on 2015-09-25T21:12:10Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3111543.pdf: 8764325 bytes, checksum: 92be3095214eecdfca7241495279e42f (MD5) Previous issue date: 2003 Embargo set by: Seth Robbins for item 85082 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 136 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2003. http://hdl.handle.net/2142/83801 (MiAaPQ)AAI3111543 eng Engineering, Materials Science The Deformation and Fracture of Thick Thermal Barrier Coatings text Mechanical Engineering Mechanical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.