Thermomechanical peeling in multilayer beams and plates-a solution from first principles

The purpose of this paper is to present a solution for the peeling moment arising from the peeling stress distribution in any interface in a multilayer beam or plate. The solution is implemented for three- and four- layer beams; it is shown that it can readily be implemented for any desired number of layers. The solution is derived from first principles, and is evolved from the well known [Timoshenko, A. 1925. Analysis of bi-metal thermostats. Journal of the Optical Society of America, 11, 233-255] bimetal thermostat analysis. A physical interpretation of the factors that make up the peeling moment is given, enabling quick identification of how any layer property may be changed in order to resist delamination at any interface of interest. The concept of moments being transferred across the interface to cause equal radii of curvature is helpful in understanding the factors that influence the magnitude and direction of the peeling moment at any interface. This analytical method applies equally to multilayer stack-ups cured simultaneously at a common temperature, and to products such as integrated circuit wafers where the layers are formed sequentially at different temperatures.