Stress Assessment in Artistic Materials Using a Micro-Scratching Technique

Abstract

The paper presents an experimental procedure based on micro-scratching to detect stresses in the ground layer of panel paintings. The method relies on the fact that cracking of the material during a micro-scratching test is the outcome of a combination of local force applied by an indenter and the stresses present in the material. The critical normal load at which damage appears during the test has a strong correlation with the stress in the material. The method, although not providing absolute values of stress, is sensitive to stress magnitude and direction, only micro-destructive, and attractive for monitoring stress changes caused by relaxation processes also in multi-layer materials. The presented tests were performed on artistic materials for which information on stress relaxation is particularly important when developing strategies for their storage and transportation.