Damage law identification from full field displacement measurement: Application to four-point bending test for plasterboard

• DIC is used to follow the kinematics along a four-point bending test on plasterboards.
• Identification of a homogenized continuum description (damage law) is performed.
• Identification accounting for experimental imperfections.
• Identification procedure provides constitutive parameters with small variability.

Plasterboards are tested in four-point bending up to failure, and digital image correlation is used to follow the kinematics and the progressive degradation of the structure all along the test. Although numerous distinct core cracks are clearly observed, it is proposed to identify the behavior of plasterboard through a homogenized continuum description where the progressive degradation of the bending stiffness is described through a damage law. A specific procedure for the identification is presented where experimental imperfections and symmetry breakdown are accepted and accounted for. The identification procedure is shown to provide constitutive parameters with a remarkably small variability.