Mechanics of solids and structures @ UNIBS


Research

Structural as well as material deformation and failure cannot be understood at a single scale alone: they require the investigation of multiple scales to capture the progression of the fundamental physical mechanisms. The breakdown of the basic constituents of any material ultimately leads to the failure of its overall structure and intended function. Materials failure, ranging from the earth crust in earthquakes, to the collapse of buildings, to the swelling and fracturing in energy storage materials, to bio-chemo-mechnical effects in cells and living tissues, impacts on millions of lives and is a major issue in the health and wealth strategic plan of UNIBS. The group of Mechanics of Solids ans Structures, with its Applied Seismology and Structural Dynamics Research Center, and its Multiscale Mechanics and Multiphysics of Materials Lab frame in this vibrant context.

Centers and labs


CeSiA - Applied Seismology and Structural Dynamics Research Center

m4lab - Multiscale Mechanics and Multiphysics of Materials Lab



Interests 

Cold compacted powder materials.

We develop co-designed experimental, theoretical, and numerical investigations aiming at estimating the value of the material properties for cold compacted powder materials.  The concept of image-based modeling is used to reconstruct the morphology of the powder structure with high fidelity. 
Analyses on aluminum powder pellets provided significant understanding of the microstructural mechanisms that preside the increase of the elastic properties with compaction. The role of the stress percolation path and its evolution during material densification is highlighted. Those insights allowed formulating  micro-mechanical based phenomenological theories.


Crack enucleation and propagation due to hydrogen embrittlement in metals.


This work, in cooperation with the international company Tenaris, concerns the analysis, the implementation in the Abaqus FEM code, and the validation of coupled volumetric models of hydrogen diffusion, mechanical stress and damage.



Crack propagation modeling in brittle materials: numerical simulations, multiscale analysis, plasticity analogies, SIF evaluation algorithms, real-life applications.

This research frames the problem of three-dimensional quasi-static crack propagation in brittle materials into the theory of standard dissipative processes.Variational formulations are stated. They characterize the three dimensional crack front quasi-static velocity as minimizer of constrained quadratic functionals. An implicit in time crack tracking algorithm that computationally handles the constraint via the penalty method algorithm is introduced. Novel outcomes arising from a visco-plastic regularization allows 3D crack tracking and solution of real-life applications.






Earthquake Ground Motion Prediction and Reduction of Seismic Vulnerability.

Effective mechanical properties of polycrystalline metals, with particular focus on the size effects

We develop strain gradient plasticity models accounting for dislocation mechanics with the purpose of describing the size effects observed in metal components in the size range spanning from a few tens of nanometers to a few tens of micrometers.   

Effective mechanical behavior of syntactic foams

Wedevelop micromechanical models to predict the effective properties of syntactic  foams, with particular emphasis on the quasi-brittle failure of glass microballoons/thermoset matrix systems at very high filler volume fraction.








Electro-chemo-mechanical behavior of Ionic Polymer Metal Composites

We study the electrochemomechanics of Ionic Polymer Metal Composites (IPMCs)  with the purpose of developing predictive models for IPMCs' sensing, actuation, and energy harvesting.


Mechanical behavior of composite structures

This research focuses on developing structural models for the accurate estimate of the stress field in sandwich panels and other composite structures subject to relevant boundary layer effects.


Mechanics of Energy Storage Materials: multi-scale and multi-physics analysis of swelling due to diffusion of species in Li-ion batteries. 

A multi-scale and multi-physics model of the phenomena that lead to degradation and mechanical failure in electrodes is the concern of the present research. In recent publications, we tailored the computational homogenization technique to model the events that coexist during batteries charging and discharging cycles. At the macro-scale, diffusion-advection equations model the coupling between electrochemistry and mechanics in the whole cell. The multi-component porous electrode, migration, diffusion, and intercalation of Lithium in the active particles, the phase-segregation and swelling of the latter are modeled at the micro-scale. A rigorous thermodynamics setting is stated and scale transitions are formulated. 



A novel model for lithiation in active particles is coupled to a Maxwell's equations basedformulation for the ionic motion in the (liquid) electrolyte. Image-based modeling techniques have been applied in order to reconstruction the porous electrode microstructure. High-performance computing implementations via Abaqus and deal.II have been carried out.
https://sites.google.com/a/unibs.it/scienza-delle-costruzioni-unibs/ricerca/cellmesh.png



Mechanobiology


We recently studied how multi-physics interactions drive tumor growth factors relocation on endothelial cells.Co-designed experiments and modeling} allow identifying three phases of the receptor dynamics, which are controlled respectively by the high chemical reaction rate, by the mechanical deformation rate, and by the diffusion of free receptors on the membrane. The identification of the laws that regulate receptor polarization opens new perspectives toward developing innovative anti-angiogenic strategies through the modulation of EC activation.




Major Research Projects - last 5 years

  1. Virtual batteries: multiscale, multiphysics, and HPC for the next generation of energy storage materials, HPC-Europa3 Transnational Access programme,  2018.

  2. Swelling and Fracturing in Lithium Batteries electrodes during Charging/Discharging Cycles (LiSF) MARIE CURIE ACTIONS - Intra-European Fellowships (IEF) 2012.
  3. Crack enucleation and propagation due to hydrogen embrittlement in metals. Funded by Tenaris SpA, 2013-15



International collaborations- in alphabetical order

  • L. Banks-Sills, Tel Aviv University, Israel;
  • J. Berger, Colorado School of Mines, USA;
  • A. Bower, Brown University, Providence, USA;
  • M. Geers, P. Notten, D. Danilov, TU/e, the Nederlands;
  • N. Gupta, M. Porfiri, New York University Tandon School of Engineering, USA;
  • A. Ingraffea, P. Wawrzynek, D. Warner, Cornell University, Ithaca, USA;
  • J.B. Leblond, Université Pierre et Marie Curie (Paris VI), France;
  • J. Llorca, J. Segurado, Universidad Politécnica de Madrid
  • V. Mantic, F. Paris, L. Tavara, Universidad de Sevilla, SP;
  • E. Martínez-Pañeda, University of Oviedo, SP
  • S. Mogilevskaya, University of Minnesota at Minneapolis, USA
  • K. Matous, Notre Dame University, USA;
  • R. Mc Meeking, University of California at S. Barbara, USA;
  • C.F. Niordson, Technical University of Denmark
  • J.R. Willis, Department of Applied Mathematics and Theoretical Physics, University of Cambridge