Tailoring metallic-organic interfaces to improve product reliability
Metal-polymer laminates are increasingly used in food and beverage packaging. Pre-coating packaging steels leads to a significant reduction of the environmental impact of the production process. During production, the material is subjected to large deformations at increased temperatures and high strain rates. Throughout this process, the metal-polymer interface roughens, due to deformation-induced roughening of the steel surface. After production, the material may not exhibit any interface damage, even after a relatively long shelf-life period, as this damage triggers corrosion and compromises the content quality. This research studies the effect of roughening on the interface integrity.
A new methodology to experimentally determine the three-dimensional surface deformation field has been developed. Global Digital Image Correlation is applied to extract the surface deformation from evolving surface height profiles. The displacement fields, extracted from a tensile experiment on packaging steel, reveal the full-field kinematics accompanying the roughening mechanism.
The extracted surface displacements are next applied in a two-dimensional numerical model consisting of a polymer layer with cohesive zone elements describing the polymer-steel interface.
With the predictions, specific steel and polymer properties can be tailored to reduce or even prevent damage and therefore improve the long-term reliability of products manufactured out of these materials.