Effect of surface residual stress on the fracture of double cantilever beam fracture toughness specimen

This paper studies the influence of surface residual stress on the fracture of the double cantilever beam (DCB) specimens. The closed-form solutions of the energy release rate and the stress intensity factor are derived by using Timoshenko beam theory. Results show that positive residual surface stress and the root effect of the DCB enhance the energy release rate and the stress intensity factor. The root effect cannot be neglected if the thickness of the beam is at the nanoscale (e.g., less than 100"‰nm), even though the ratio of beam length to thickness is larger.