Non-linear flow, fracture, mechanical quenching, and computer modeling of a glass cylinder pressed between parallel plates
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Case Western Reserve University School of Graduate Studies / OhioLINK
1992
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=case1056478895 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-case10564788952021-08-03T05:30:45Z Non-linear flow, fracture, mechanical quenching, and computer modeling of a glass cylinder pressed between parallel plates Sakoske, George Emil Non-linear flow fracture mechanical quenching computer modeling glass cylinder Analytical, experimental, and computer modeling studies are conducted for axial pressing of a glass cylinder between parallel plates. The classic "no-slip" parallel plate equation is derived from fundamental fluid mechanics with no geometric limitations and its validity is proved for transient and steady state low Reynold's number flow. Similarly, a "perfect-slip" solution yields the fiber elongation equation ς = 3ηdotvarepsilon. These limiting boundary conditions are studied experimentally by pressing directly on graphite and mica providing slip mechanisms, and non-deformable metal discs for no-slip. Linear, non-linear flow, and elastic fracture are observed by varying time scale over which strain is applied, θ, in relationship to glass structural relaxation time, τ. Linear flow is measured for τllθ in a soda-lime glass over the range 10<sup>7.5</sup>leη ole 1012.8 Pacdotsec. Shear components of τ~20 sec non-linear flow agree with other non-linear viscometric studies. A bond breakage and re-formation rate process model is applied to better fit "steady-state" viscosity strain-rate results. Initial t~0 and transient data demonstrate complex time, stress, strain, strain-rate behavior. An energy balan ce shows viscous dissipation contributes significantly to viscosity decreases measured during forced rate pressing of glass cylinders. Rate dependent flow shapes are filmed. Mica did not significantly reduce loads but allows more flow before fracture. Ability to transmit shearing stresses and breakdown of "slip" boundary material is discussed. Fracture occurs as stresses increase within the sample for increasing time and rates. Cracks are driven by hoop and radial stresses where the origin and mode is a function of pressing rate. A Maxwell fluid finite element model is developed which uses experimental parameters as input. FEM results show general agreement with analytical solutions. A viscous heating analysis brings insight to stress overshoot and rate dependent shape. Conduction and radiation are shown to be important mechanisms affecting the bulge shape. Heat transfer to thermal boundaries is limited by the glass conductivity. Internal stress distributions and fracture modes are predicted. Shearing stresses are the significant component which may nucleate cracks that are then driven by radial and hoop stresses. Mechanical quench experiments demonstrate stress-strain induced lattice structure deformations. At T = 570°C a 110 MPa mechanical quench increases density ~0.13% and produces internal axial compression and biaxial hoop-radial tension of ~10 MPa. Dilatometric recoveries show radial strain increases ~0.08% and axial strain decreases ~0.25% correlating to density changes and the phenomenon known as "delayed elasticity." 1992 English text Case Western Reserve University School of Graduate Studies / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=case1056478895 http://rave.ohiolink.edu/etdc/view?acc_num=case1056478895 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Non-linear flow fracture mechanical quenching computer modeling glass cylinder |
| spellingShingle |
Non-linear flow fracture mechanical quenching computer modeling glass cylinder Sakoske, George Emil Non-linear flow, fracture, mechanical quenching, and computer modeling of a glass cylinder pressed between parallel plates |
| author |
Sakoske, George Emil |
| author_facet |
Sakoske, George Emil |
| author_sort |
Sakoske, George Emil |
| title |
Non-linear flow, fracture, mechanical quenching, and computer modeling of a glass cylinder pressed between parallel plates |
| title_short |
Non-linear flow, fracture, mechanical quenching, and computer modeling of a glass cylinder pressed between parallel plates |
| title_full |
Non-linear flow, fracture, mechanical quenching, and computer modeling of a glass cylinder pressed between parallel plates |
| title_fullStr |
Non-linear flow, fracture, mechanical quenching, and computer modeling of a glass cylinder pressed between parallel plates |
| title_full_unstemmed |
Non-linear flow, fracture, mechanical quenching, and computer modeling of a glass cylinder pressed between parallel plates |
| title_sort |
non-linear flow, fracture, mechanical quenching, and computer modeling of a glass cylinder pressed between parallel plates |
| publisher |
Case Western Reserve University School of Graduate Studies / OhioLINK |
| publishDate |
1992 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=case1056478895 |
| work_keys_str_mv |
AT sakoskegeorgeemil nonlinearflowfracturemechanicalquenchingandcomputermodelingofaglasscylinderpressedbetweenparallelplates |
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