Determination of the Total Stresses

Abstract

When we want to determine the actual residual stresses which are present in a glass sheet, we can superpose the thickness stresses and the membrane stresses if they have been measured separately. But this process takes a rather long time and, moreover, it has two main drawbacks: 1) on the one hand this method is destructive since in order to measure the thickness stresses we have to use a small sample cut out from the plate; 2) on the other hand bending stresses may remain unnoticed since they vanish at the time of the cutting of the sheet and their measurement is impossible with transmitted light because their integral across the thickness is equal to zero.