stress distribution in thermally tempered glass panes near the edges, corners and holes : Part 2. Distribution of thermal stresses

Abstract

With temperature profiles during the thermal strengthening process determined in part 1 of this paper, the distribution of thermal stresses for the central area, near the edges and holes of the glass plates are calculated numerically with the help of a fmite-elementsimulation (THERVO PRO) which models the formation of temper stresses with time. Comparison with existing experimental data for the central area (zone 1) shows very good correspondence with numerical results. For zone 2 (edge), at about a distance d away from the edge, a somewhat reduced surface compression due to membrane stresses is observed. At zone 2 and zone 3 (corner) surface compression is found parallel to the edge surfaces, since due to equilibrium requirements there is no thermally induced stress perpendicular to the surfaces. In general, near the edge and corner stress distribution is three-dimensional as well as around zone 4 (hole). The hole with a cone has a certain difference compared with a cylindrical hole: it does not have a reduction of tangential surface compression at some distance from the hole on the cone side.