On the simulation of the flaking paint due to internal stresses: A simple model

We present a simple theoretical and experimental model to explain the flaking off of paints, from a pre-existing defect, due to the influence of internal stresses provoked by the variation of ambient temperature and a long or strong illumination. The experimental model is made of two superimposed rubber strips, one of them being submitted to an instantaneous elongation or to a constant speed of strain. The detachment of the other strip, that represents the peeling and the flaking off of the paint layer, is measured and analyzed using concepts of the fracture mechanics, such as the strain energy release rate, in order to determine the conditions of stability and propagation of a crack at the interface, and to draw a master curve representing the dissipation function as a function of the crack propagation speed.