Prediction of coating adhesion loss due to stretching

Polymer coated sheet metals are widely used for part fabrication in industry. To ensure that the manufactured products can meet the service life requirement, the effect of plastic deformation on coating adhesion is a critical concern. This paper presents an investigation of coating adhesion loss in forming polymer-coated sheet metals. A set of experiments were conducted to evaluate the pull-off strength of coatings before and after uniaxial stretching. The experiments show that axial plastic deformation can cause adhesion to deteriorate. An analytical method based on a virtual interface crack model was developed to evaluate the adhesion potential and was used to quantitatively predict the adhesion loss of two polymer coated sheet metals. The prediction results are in good agreement with the experimental measurements. A parametric study was also conducted to investigate the effects of material properties and coating/substrate thickness on adhesion loss. The results of this study can be used to attain better product design and application development for polymer coated sheet metals.