Fracture mechanics of microstructured composites
incorporating intrinsic length-scales

Project Homepage


Research AreaFP7-PEOPLE-2013-CIG
Project Reference PCIG13-GA-2013-618375-MeMic
CoordinatorProf. Davide Bigoni
ResearcherProf. Andrea Piccolroaz
Project Funding100 k€
Contract TypeCareer Integration Grant
Start Date2013-09-01
Duration48 months

PROJECT DESCRIPTION

Inspired by biological systems, artificial composite materials nowadays may be micro-tailored with a hierarchical structure, or may be produced with sculptured chiral structures, or with stabilized negative-stiffness inclusions. The result is that these new materials can achieve surprisingly excellent mechanical properties. For instance: composite materials produced with inclusions of barium titanate in a tin matrix may exhibit a viscoelastic modulus far higher than that of either constituent, reaching a stiffness substantially greater than that of diamond; these materials are proved to be stable even with negative-stiffness constituents; polymeric adhesives embedding hard plastic microfibers, inspired by gecko's keratin fibre arrays, can exhibit smart directional adhesion effects and can be attached and detached repeatedly; composite structures mimicking human skin and embedding three-dimensional microvascular networks are shown to create new self-healing materials. Moreover, a hierarchical heterogeneous microstructure can give extremal values of material properties such as negative Poisson's ratio. The technological application of these new high-performance composite materials is limited by fracture nucleation and propagation at nano and micro scales. In fact it is very difficult to simultaneously achieve high values of strength and toughness, for which ordinarily there is a trade-off. The aim of this project is the development of new models of fracture mechanics for innovative composite materials, bridging together the different length-scales and thus overcoming the main limitations of linear fracture mechanics. The goal will be achieved by a novel multiscale approach to fracture mechanics combining continuum and discrete modelling. In particular, at the microscale the heterogeneous microstructure of the composite material will be described as a continuum micropolar medium incorporating appropriate length-scales, thus capable of capturing size-effects. At the nanoscale the discrete structure of the material will be described in terms of lattice models in order to understand the mechanism of dissipation and the properties of waves generated by propagating cracks. The continuum and discrete modelling will be combined through the concept of structural interface, where a discrete structure representing the interface of finite thickness is embedded in a continuum body. Moreover, the homogenization of the discrete structure will lead to the derivation of nonlocal interface models, thus providing a link between atomistic (discrete) and macroscopic (continuum incorporating length-scales) points of view and promoting a better understanding of fracture mechanisms in materials with microstructure.


ACKNOWLEDGEMENT

This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no PCIG13-GA-2013-618375.


Publications


Completed
  • Mishuris, G., Miszuris, W., Ochsner, A. and Piccolroaz, A. (2013)
    Transmission conditions for thin elasto-plastic pressure-dependent interphases. In: Plasticity of Pressure-Sensitive Materials.
    Altenbach, H., Ochsner, A., Eds., Springer-Verlag, Berlin.
    http://dx.doi.org/10.1007/978-3-642-40945-5_4

  • Piccolroaz, A., Movchan, A.B. (2014)
    Dispersion and localization in structured Rayleigh beams.
    International Journal of Solids and Structures, 51, 4452-4461.
    http://dx.doi.org/10.1016/j.ijsolstr.2014.09.016

  • Sonato, M., Piccolroaz, A., Miszuris, W., Mishuris, G. (2015)
    General transmission conditions for thin elasto-plastic pressure-dependent interphase between dissimilar materials.
    International Journal of Solids and Structures, 64-65, 9-21.
    http://dx.doi.org/10.1016/j.ijsolstr.2015.03.009

  • Bordignon, N., Piccolroaz, A., Dal Corso, F., Bigoni, D. (2015)
    Strain localization and shear band propagation in ductile materials.
    Front. Mater. 2:22.
    http://dx.doi.org/10.3389/fmats.2015.00022

  • Bacigalupo, A., Morini, L., Piccolroaz, A. (2015)
    Multiscale asymptotic homogenization analysis of thermo-diffusive composite materials.
    International Journal of Solids and Structures, under review.

Preprints
  • Piccolroaz, A., Movchan, A.B. (2014)
    Dispersion and localization in structured Rayleigh beams.
    Preprint: http://arxiv.org/abs/1408.5020.

  • Sonato, M., Piccolroaz, A., Miszuris, W., Mishuris, G. (2015)
    General transmission conditions for thin elasto-plastic pressure-dependent interphase between dissimilar materials.
    Preprint: http://arxiv.org/abs/1501.02919.

  • Bordignon, N., Piccolroaz, A., Dal Corso, F., Bigoni, D. (2015)
    Strain localization and shear band propagation in ductile materials.
    Preprint: http://arxiv.org/abs/1501.06024.

  • Bacigalupo, A., Morini, L., Piccolroaz, A. (2015)
    Multiscale asymptotic homogenization analysis of thermo-diffusive composite materials.
    Preprint: http://arxiv.org/abs/1503.09128.

Under preparation
  • Piccolroaz, A., Movchan, A.B.
    Dispersion degeneracies in flexural waves supported by Rayleigh beam structures.

  • Gorbushin, N., Piccolroaz, A., Mishuris, G.
    Crack dynamics in a bimaterial lattice.

  • Piccolroaz, A., Mishuris, G., Wrobel, M.
    Fourth mode in fracture mechanics of a crack driven by viscous fluid.


Dissemination


Organization of workshops and minisymposia
  • Meccanica e Materiali, Modellazione non locale dei materiali.
    XXII Congresso - Associazione Italiana di Meccanica Teorica e Applicata.
    Co-organized with Andrea Bacigalupo (IMT Institute for Advanced Studies Lucca) and Francesco Dal Corso (Univeristy of Trento).
    Genova, Italy, 14-17 September 2015.

Conference participation
  • Piccolroaz, A., Movchan, A. (2014)
    Analogy between structural elements and materials with microstructure.
    Marie Skłodowska-Curie Conference: ESOF 2014.
    Copenhagen, Denmark, June 19-20, 2014.

  • Piccolroaz, A. (2014)
    Incorporating intrinsic length-scales in fracture toughness of microstructured ceramics.
    Advanced Problems in Mechanics 2014.
    St. Petersburg, Russia, June 30 - July 5, 2014.

  • Piccolroaz, A., Mishuris, G. (2014)
    Dynamic fracture in bimaterial lattices.
    3th International Conference on Fracture Fatigue and Wear (FFW 2014).
    Kitakyushu, Japan, September 1-3, 2014.

  • Piccolroaz, A. (2015)
    Fracture in ceramics with microstructure. Accounting for size-effects.
    Advanced Problems in the Mechanical Modelling of Ceramic Materials, Energy Materials Nanotechnology Meeting on Ceracmics (EMN 2015).
    Orlando, Florida, January 26-29, 2015.

  • Piccolroaz, A., Movchan, A. (2015)
    Dispersion and localization in structured Rayleigh beams
    Meccanica e Materiali, Modellazione non locale dei materiali
    XXII Congresso - Associazione Italiana di Meccanica Teorica e Applicata.

    Genova, September 14-17, 2015.

Contacts

Prof. Davide Bigoni
Dipartimento di Ingegneria Civile, Ambientale e Meccanica
Università di Trento, via Mesiano, 77 I-38123 Trento (Italia)
Tel: +39 0461 282522
Fax: +39 0461 282599
E-mail: bigoni@ing.unitn.it

Dr. Andrea Piccolroaz
Dipartimento di Ingegneria Civile, Ambientale e Meccanica
Università di Trento, via Mesiano, 77 I-38123 Trento (Italia)
Tel: +39 0461 282583
Fax: +39 0461 282599
E-mail: roaz@ing.unitn.it