Wednesday, May 22th, 2019. Time: 12h
Place: O.C. Zienkiewicz Conference Room, C1 Building, UPC Campus Nord, Barcelona
It is well known that by deforming a special class of materials (piezoelectrics) electricity can be produced. This functionality makes piezoelectrics ubiquitous in sensors, actuators, and energy harvesting systems. What is a relatively new discovery is that by bending any dielectric at the nanoscale, significant electrical transduction can also be achieved. This is the so-called flexoelectric effect, a far less known and understood phenomenon by which electric polarization is coupled to strain gradients. Flexoelectricity is present in a much wider variety of materials, including non-polar dielectrics and polymers, but is only significant at small length-scales, where high strain-gradients develop.
The key goal of this study is to identify through computational exploration design concepts for metamaterials or composites that constructively accumulate the flexoelectric effect of nonpiezoelectric micro-structural elements, and make it available as an effective piezoelectric response at larger scales. If properly designed, an effective homogeneous deformation on the composite may create substantial strain gradients (and polarization) in its non-piezoelectric constituents. In order to achieve this goal, we face several challenges, both computational and conceptual. In this talk I will discuss how we have addressed the computational challenge of numerically approximating the 4rth order partial differential equations of continuum flexoelectricity, based on an Immersed Boundary Hierarchical B-spline approach. I will discuss how these computations allow us to properly interpret experiments, predict new mechanical phenomena, and help us conceive flexoelectric metamaterials.
IMPORTANT NOTE! From March 2019 registration is mandatory. The access is open and free, but it is necessary to register before attending. Please, fill in the following form if you want to attend the seminar.