Double cantilever beam fracture toughness measurement method for glass

A simple method of measuring Mode I fracture toughness, K-IC, of glass using the double cantilever beam (DCB) geometry is presented. An inert atmosphere is created at the crack tip to prevent subcritical crack growth and enable pinning the crack while the specimen is loaded to failure. This was achieved experimentally using liquid toluene or a glovebox with dry argon. K-IC values measured by this method showed good agreement with published literature values for selected glasses. Applicability of the analytical stress intensity factor solution based on crack length, crack front curvature, and the height of the crack guiding groove are confirmed through experimental data and finite element analysis. The experimentally observed crack front curvature, which leads near the edges for small groove heights and leads in the center for larger groove heights, is predicted from the geometry of the DCB specimen for a linear elastic solid through finite element modeling.

Automated summary

This paper presents a simple method for measuring the Mode I fracture toughness, K-IC, of glass using the double cantilever beam (DCB) geometry. An inert atmosphere is used to prevent subcritical crack growth and pin the crack during the specimen's failure. Experimental results show good agreement between the K-IC values measured by this method and the published literature values for selected glasses. The applicability of an analytical stress intensity factor solution based on crack length, crack front curvature, and crack guiding groove height is confirmed through experimental data and finite element analysis. The crack front curvature observed experimentally is predicted using finite element modeling based on the geometry of the DCB specimen.