research

A short overview of micromechanical models of hierarchical materials (hybrid composites, biomaterials, fractal materials, etc.) is given. Several examples of the modeling of strength and damage in hierarchical materials are summarized, among them, 3D FE model of hybrid composites with nanoengineered matrix, fiber bundle model of UD composites with hierarchically clustered fibers and 3D multilevel model of wood considered as a gradient, cellular material with layered composite cell walls.

Can a torque induce longitudinal motion of an elastic rod?

See the explanation and an example of use of the 'torsional gun' at http://www.ing.unitn.it/~bigoni/torsional_locomotion.html

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High-performance stretchable electronics have to utilize high-quality inorganic electronic materials such as silicon, oxide or nitride dielectrics, and metals. These inorganic materials usually crack or yield at very small intrinsic strains, for example, 1%, whereas bio-integrated electronics are expected to at least match the stretchability of bio-tissues (20%) and deployable structure health monitoring networks are expected to expand from wafer scale (several centimeters) to cover macroscopic structures (several meters).

In a pure liquid, molecules touch one another but change neighbors frequently.  External forces cause the liquid to change shape by viscous flow.  Thermal agitation causes  molecules to undergo self-diffusion.  The two phenomena--viscous flow and self-diffusion--often result from a single rate-limiting process:  molecules change neighbors.  This simple picture is amply confirmed by the Stokes-Einstein relation, which links the viscosity and self-diffusivity for many liquids over wide ranges of temperature.

Soft Matters, (2014) Advance article

Recent experiments showed that the Lode parameter, which distinguishes between axisymmetric and shear dominated stress states, has a profound effect on material ductility, especially at low stress triaxiality. Consequently, the theoretical framework for void growth and coalescence is currently being revisited, which often involve performing representative volume element (RVE) calculations. The present study investigates an RVE composed of a cubic unit cell containing a spherical void at its center.

http://hdl.handle.net/10993/12316

http://orbilu.uni.lu/handle/10993/17878

http://hdl.handle.net/10993/17878