Effect of glass temperature before cooling and cooling rate on residual stresses in tempering
Tutkimustuotos › › vertaisarvioitu
|Julkaisu||Glass Structures Engineering|
|Varhainen verkossa julkaisun päivämäärä||5 joulukuuta 2017|
|DOI - pysyväislinkit|
|Tila||Julkaistu - maaliskuuta 2018|
Understanding of heat transfer and development of the temperature field in a glass during tempering is very important because it affects the quality. By numerical modeling, it is possible to study the effect of glass temperature before cooling and the values of heat transfer coefficients which determine the cooling rate and material properties on transient and residual stresses during cooling. Also, the effect of thermal and mechanical properties of glass, which are obtained experimentally, can be easily observed. In the present study, the tempering process of glass sheets with different glass thicknesses has been simulated. The paper presents modeling results, which explain the effect of the initial temperature before cooling and cooling rate on the residual and transient stresses of glass sheets of different thicknesses. The paper also shows that results can be presented independent of glass thickness by using two variables: the maximum temperature difference between surface and mid-plane during the cooling and the difference between glass transition and glass initial temperature. Because the mechanical properties of glass are experimental and are not very accurately known, the effect of their variation on residual stresses is also shown.