Numerical Simulation of Stress Field in Physical Tempering Process of Flat Soda Lime Silica Glass

Based on the analysis of different theory for glass tempering process, the “structural theory” with stress relaxation and structural relaxation effects was selected to investigate the tempering of flat glass quantificationally. The geometrical model with small size and non-homogeneous mesh were considered to build the finite element models according to the characteristics of stress field. The tempering process of flat glass with 12 mm thickness was calculated with the verified finite element model. The transient and permanent stress of the central area, edge and corner end of the flat glass are obtained and analyzed. From the calculation results of basic case, the transient tensile stress at the upper surface of the central area, the center point of edge, the edge of edge, the edge of corner were 14.30,18.94, 40.76 and 34.75 MPa, respectively. The transient tensile stress at these points were dangerous to promote the glass to break during the tempering. In addition, the point at the diagonal line of symmetry plane in the thickness direction, which is 14 mm from corner, has the maximum permanent tensile stress about 70.01 MPa in the flat glass after tempering. Thus, it is indicated that the corner is the weakest region in the tempered glass.