Coatings and Multi-Layered Systems: Multiiscale Failure Modeling and Experiments
Philippe H. Geubelle, PhD, Bliss Professor and Head of Aerospace Engineering, University of Illinois, Urbana-Champaign
Heterogeneities are often present in adhesives, coatings and multi-layered systems. Some come in the form of second-phase particles used to improve the fracture properties and/or to provide multifunctionality. Others are associated with intrinsic factors such as the roughness of the adherent or substrate interface, and to a difference in the composition of the polymer itself in the region immediately adjacent to the interface.
To model the failure of these systems, we present a multiscale cohesive framework that relates the damage processes taking place at the microscale in the adhesive layer or coating to the cohesive traction-separation law that is used to model the failure of the bonded structure at the macroscale. At the microscale, we perform molecular dynamics (MD) and coarse-grained simulations aimed at capturing the impact of the heterogeneous composition of the polymer in the immediate vicinity of the film/substrate interface on the constitutive and failure properties of interface. In the case of heterogeneous adhesives, the subscale model also includes continuum finite element simulations of damage evolution taking place in the vicinity of the second-phase particles.