Date of Award
12-2009
Document Type
Thesis
Degree Name
Master of Science (MS)
Legacy Department
Mechanical Engineering
Committee Chair/Advisor
Blouin, Vincent
Committee Member
Joseph , Paul
Committee Member
Richarson , Kathleen
Committee Member
Thompson , Lonny
Committee Member
Miller , Richard
Abstract
Glass viscoelasticity has gained importance in recent years as glass lens molding appeared as a valuable alternative to the traditional grinding and polishing process for manufacturing glass lenses. In the precision lens molding process, knowledge of viscoelastic properties of glass in the transition region, which affect the stress relaxation behavior, is required to precisely predict the final size and shape of molded lenses. The purpose of this study is to establish a step-by-step procedure for characterizing the viscoelastic behavior of glass in the glass transition region using a finite term Prony series of a Generalized Maxwell model. This study focuses on viscoelastic characterization of stabilized glass samples at lower stress levels between 3 and 12 MPa where it demonstrates linearity. Analysis and post-processing of creep data, performed in MATLAB and MAPLE, include displacement-to-strain conversion, determination of viscoelastic moments and constants, normalization, curve fitting and retardation-to-relaxation conversion. The process of curve fitting is carried out using a constrained optimization scheme to satisfy the constraint equations involving viscoelastic constants and functions. A set of relaxation parameters needed in numerical modeling, i.e., weights and times of the Prony series are presented in this thesis for borosilicate glass at different temperatures. Additionally, the issues related to the characterization of optical glasses were identified and discussed.
Recommended Citation
Kadali, Hemanth, "EXPERIMENTAL CHARACTERIZATION OF STRESS RELAXATION IN GLASS" (2009). All Theses. 704.
https://open.clemson.edu/all_theses/704