03.10.24 - Antoine Sanner "Elastic instabilities in the adhesion of soft solids and in the fracture of polymer networks"

Elastic instabilities in the adhesion of soft solids and in the fracture of polymer networks

 The fracture energy, or toughness, of most materials and interfaces exceeds the prediction by Griffith based on energy conservation. A common source of this excess fracture energy is dissipative material behavior, such as viscoelasticity and plastic flow. However, this excess in fracture energy can also emerge from elastic instabilities, independently of material specific energy dissipation.
 
  When separating soft, sticky solids, surface roughness triggers elastic instabilities dissipating energy. We introduce a crack-perturbation model that quantitatively links the increase in fracture energy caused by these instabilities to the statistical parameters of the surface roughness.
 
  In polymer networks such as gels and elastomers, the discreteness of the network causes instabilities during crack propagation.  We model these soft materials using a coarse-grained spring-network and determine the impact of instabilities and network disorder on the fracture toughness.