Effects of vibration fatigue on mechanical parameters of representative numerical models of painted wooden heritage objects

Painted wooden heritage objects are complex multilayered systems strongly affected by environmental conditions. In addition to variations of thermohygromechanical properties among layers, which can induce stresses leading to delamination and cracking, observations in museum environments have reported damage likely caused by vibrations such as paint flaking and cracking, leading some institutions to implement preventive measures. While the impact of climatic variations has been widely studied, the consequences of long-term low-level vibrations remain poorly understood, whereas they generate material fatigue that may catalyse other degradation mechanisms. Understanding and quantifying the effect of long-term vibrations on such multilayered systems would greatly improve conservation strategies. For this purpose, this work proposes to assess the vibration fatigue condition of a material by measuring the evolution of its mechanical properties and correlating it to the microcrack formation. The study is carried out on wood/gesso beams that are subjected to vibrations in the 1–200 Hz range, a frequency band in which objects displayed in museums are typically excited. The evolution of vibration properties and (micro)crack formation are studied with finite element models taking into account damaging and plasticity.