Résumé
DCDC is widely used to study sub-critical crack propagation in brittle materials due to elevated crack propagation stability. This quality has made this test suitable for in-situ AFM observations of the neighbourhood of the crack tip at low propagation velocities. In a recent work we reported direct evidence of the presence of a submetric liquid condensate at the crack tip of a fused silica glass. The AFM phase imaging technique allows measuring the condensation length as a function of the applied stress intensity factor and relative humidity. In order to relate this length to a critical condensation distance between the opposite crack surfaces, a detailed knowledge of the crack opening is required. We realized an experimental investigation of the crack opening profile by reflection interferometry and compared the results with a 2D finite element simulation of a cracked DCDC specimen including the mechanical effect induced by the liquid condensation.