Understanding the mechanical behaviors of soft materials, especially those involving fracture and adhesion, is critical for evaluating the mechanical reliability of emerging applications such as soft robotics and biomedical implants.  However, experimental characterization of the large deformation field in soft materials has been challenging. I will present our recent efforts to map the large deformation field by optically tracking the displacements of randomly distributed tracer particles. Using a soft silicone elastomer as a model system, we demonstrate that the particle tracking method is capable of resolving the highly concentrated nonlinear deformation field at crack tip.  We also apply the particle tracking method to characterize mixed-mode crack propagation in an elastomer and rate-dependent crack propagation in a viscoelastic gel. Finally, we extend the particle tracking method to three-dimension (3D) for mapping the 3D strain field within the volume of a soft gel substrate indented and sheared by a micro-pillar.

Refreshments will be served preceding the talk, at 2:30.

Presented with support from the Ampel and Bionics groups of the UBC Department of Mechanical Engineering.