Permanent deformation of wooden panel paintings: what is the contribution of residual drying stresses ?

International audienceThis paper analyses the possible effect of residual drying stresses on thepermanent deformation of panel paintings. For this purpose, experiments were done,during which samples were submitted to several adsorption–desorption cycles toreproduce what could happen in real climatic conditions. The painted side is regarded inthis work as a sealed surface that is mimicked by insulated some faces of the sample withan aluminium sheet. The asymmetry of the moisture content profile generates a globalcurving of the sample section that is followed over time. Results show that humidityvariations in the surrounding, because acting on one single face, reduce the residualdrying stress by activating the mechano-sorptive creep. This effect gives rise to a concavecupping towards the non-painted face. This deformation does not disappear as themoisture content becomes uniform across the panel