Thermal stress analysis of annular glass-to-metal seals under thermal shock

The effect of the thermal shock test on glass-to-metal seals is analyzed by evaluating the transient thermal stresses that develop in the glass as a result of large temperature gradients. A lower bound for the strength of the glass-to-metal interface is estimated using an experimental procedure. The thermal stress analysis is performed on a model which considers the lead, the glass seal, and the base as three concentric cylinders. The transient temperature distribution in the three components is calculated by solving the two dimensional axisymmetric heat conduction equation for the glass using a finite difference method. The temperature distribution in the glass varies in the radial and axial directions. The temperature distribution is input into the thermal stress model to evaluate the transient thermal stresses in the glass using a finite element method.