# Department of Mechanics: Seminar: Jan Eliáš 2022

### Mechanism-Based Mesh Objectivity in Stochastic Computational Modeling of Quasibrittle Fracture

#### Jan Eliáš, Brno University of Technology, Czechia

1 June 2022, 11:15-12:00 CET, Room B-168 @ Thákurova 7, 166 29 Prague 6

**Abstract**:
Computational modeling of quasibrittle fracture is often conducted using the finite element method and homogeneous material representation. There are several remedies developed to diminish the spurious mesh sensitivity due to strain localization. A mechanism-based approach developed for meshes with elements larger than the fracture process zone width will be discussed. The main subject of the talk will be a recent modification of this regularization technique that takes into account a spatial randomness in the material. It will be shown that the probability distribution functions of constitutive properties must be linked to the damage state, which may evolve during the failure process. Therefore, two localization parameters are introduced to quantify damage state of each finite element. These parameters govern both (i) the energy regularization of the constitutive equation and (ii) the mesh-dependent probability distributions of constitutive properties. The model will be applied to simulate the stochastic failure behavior of quasibrittle structures of different geometries featuring different failure processes including damage initiation, localization, and propagation.

**Bio:**
Jan Eliáš is an associate professor at the Institute of Structural Mechanics, Faculty of Civil Engineering, Brno University of Technology in Brno, Czechia. He received his Ph.D. from the same university in 2009. Jan's research focus spans from general mechanics of transient and steady-state phenomena in solids to soft computing techniques such as optimizations, Monte Carlo integration and blending of probability and mechanics. His long-term attention is devoted to mesoscale discrete models of concrete mechanical behavior, recently extended by coupled multiphysical phenomena and homogenization. Jan was awarded three research projects from the Czech Science Foundation and one project from the Czech Ministry of Education, Youth and Sports. He conducted research stays with Henrik Stang at the Technical University of Denmark, Jia-Liang Le at the University of Minnesota, and Zdeněk P. Bažant and Gianluca Cusatis at the Northwestern University.