Analysis of End Stresses in Glass-Metal Bimaterial Strips

摘要

We have analyzed the shear and normal residual stresses which build up along the interface near the end of a glass-metal seal during cooling. These stresses strongly affect the measured strength of a seal. Previous treatments of this problem have identified the presence of large interfacial transverse normal and shear stresses at the ends of bimaterial joints. We show the presence of maxima and minima in both force and moment. We demonstrate that, for certain material property combinations and relative thicknesses, the interfacial moment can induce either a peel or a pinch condition at the ends of this strip. We tested this with strips of high expansion glass-ceramic sealed to 304 stainless steel and obtained qualitative agreement. Careful finite element modeling of the strips showed that peel and pinch conditions do not necessarily coincide with the sign of the singular transverse normal stress at the strip end. This sign appears to be controlled by differences in thermoelastic properties and not by relative thickness. 13 refs., 15 figs., 3 tabs. (ERA citation 13:003783)