Test method variability in slow crack growth properties of sealing glasses

The crack growth properties of several sealing glasses were measured by using constant stress rate testing in ∼2% and 95% RH (relative humidity). Crack growth parameters measured in high humidity are systematically smaller (n and B) than those measured in low humidity, and crack velocities for dry environments are ∼100× lower than for wet environments. The crack velocity is very sensitivity to small changes in RH at low RH. Biaxial and uniaxial stress states produced similar parameters. Confidence intervals on crack growth parameters that were estimated from propagation of errors solutions were comparable to those from Monte Carlo simulation. Use of scratch-like and indentation flaws produced similar crack growth parameters when residual stresses were considered.