Extrapolation of fracture mirror and crack-branch sizes to large dimensions in biaxial strength tests of class

Annealed glass disks were fractured in biaxial tension under a variety of c onditions; crack lengths prior to branching and the sizes of the mirror and mist regions were measured. The experimental results indicated the expecte d correlation between fracture stress and these fracture features, except f or an extrapolation to a consistent, clearly defined y-ntercept. Neither en vironment, surface preparation, nor the rate of applied stress was a factor in the fracture stress versus branch, mirror, or mist size relationships.