System for measuring a bending deformation of a surface of a material

A system (1) for measuring a bending deformation of a surface of a material, adapted to cooperate with a bending test machine provided with a four-point bending mounting (80) allowing to deform a test piece (70) of said material, said measurement system (1) comprising:

• a first portion comprising:
• lateral teeth (12) each comprising an end (13), configured to bear against an upper surface (71) of the test piece via said ends (13) in two respective lateral bearing areas (73),
• a first load support (20) connected to the lateral teeth (12), configured to apply to said lateral teeth (12) a constant force oriented towards the test piece (70),
• the first portion being movable in translation along an axis (A) perpendicular to the plane of the upper surface (71) of the test piece,
• a second portion comprising:
• a central tooth (32) parallel to the lateral teeth (12) comprising an end (33), configured to bear against the upper surface (71) of the test piece via said end (33) in a central bearing area (72) arranged between the lateral bearing areas (73),
• a second load support (40) connected to the central tooth (32), configured to apply to said central tooth (32) a constant force oriented towards the test piece (70),
• the second portion being movable in translation relative to the first portion along an axis parallel to the axis (A) of the first portion,
• a measuring device comprising a deformation sensor (50), the deformation sensor comprising:
• a first arm (51) connected to the first portion,
• a second arm (53) connected to the second portion,
• wherein the first arm (51) and the second arm (53) are separated from each other by a variable distance (ΔB), the measuring device being configured to measure said variable distance (ΔB) corresponding to a distance (ΔL) between the end (33) of the central tooth (32) and the ends (13) of the lateral teeth (12) during the deformation of the test piece.