Abstract
In the present paper, numerical simulation about press-molding of glass lens is investigated. Since constitutive equation of glass depend on time-history and temperature, stress relaxation is observed on the glass subjected to applied loading, and these behaviors vary drastically depending on the temperature. In the present study, creep test has been conducted to determine the thermo-viscoelastic properties of glass. The creep function obtained by the experiment has been transformed into relaxation function employing Laplace transform. Shift factor which gives the relation between the time and temperature can be determined by creep test under several temperature. In the present analysis for press-molding of glass lens, history of the temperature and its distribution is computed by unsteady heat conduction analysis prior to the analysis of cooling sequence. The total FEM analysis for press-molding are executed taking into account the nonuniformly temperature distribution in the glass lens. Residual stresses under some processing conditions are estimated, and the optimal conditions of forming process are discussed in detail.
