01320nas a2200133   4500008004100000245008300041210006900124300001400193490000700207520089100214100001801105700002201123856004101145       2017                        eng d00aOn the genesis of directional friction through bristle-like mediating elements0 agenesis of directional friction through bristlelike mediating el  a1023-10460 v233 a<p>We propose an explanation of the genesis of directional dry friction, as emergent property of the oscillations produced in a bristle-like mediating element by the interaction with microscale fluctuations on the surface. Mathematically, we extend a convergence result by Mielke, for Prandtl–Tomlinson-like systems, considering also non-homothetic scalings of a wiggly potential. This allows us to apply the result to some simple mechanical models, that exemplify the interaction of a bristle with a surface having small fluctuations. We find that the resulting friction is the product of two factors: a geometric one, depending on the bristle angle and on the fluctuation profile, and a energetic one, proportional to the normal force exchanged between the bristle-like element and the surface. Finally, we apply our result to discuss the with the nap/against the nap asymmetry.</p>1 aGidoni, Paolo1 aDeSimone, Antonio  uhttps://doi.org/10.1051/cocv/201703000898nas a2200145   4500008004100000245008300041210006900124260001300193490000800206520043400214653002000648100002600668700002200694856003600716       2011                        en  d00aGamma-convergence of energies for nematic elastomers in the small strain limit0 aGammaconvergence of energies for nematic elastomers in the small  bSpringer0 v 233 a<p>We study two variational models recently proposed in the literature to describe the mechanical behaviour of nematic elastomers either in the fully nonlinear regime or in the framework of a geometrically linear theory. We show that, in the small strain limit, the energy functional of the first one I\\\"-converges to the relaxation of the second one, a functional for which an explicit representation formula is available.</p>10aLiquid crystals1 aAgostiniani, Virginia1 aDeSimone, Antonio  uhttp://hdl.handle.net/1963/414101036nas a2200133   4500008004300000245007100043210006900114520059000183100002100773700002200794700002500816700002500841856003600866       2008                        en_Ud  00aGlobally stable quasistatic evolution in plasticity with softening0 aGlobally stable quasistatic evolution in plasticity with softeni3 aWe study a relaxed formulation of the quasistatic evolution problem in the context of small strain associative elastoplasticity with softening. The relaxation takes place in spaces of generalized Young measures. The notion of solution is characterized by the following properties: global stability at each time and energy balance on each\\ntime interval. An example developed in detail compares the solutions obtained by this method with the ones provided by a vanishing viscosity approximation, and shows that only the latter capture a decreasing branch in the stress-strain response.1 aDal Maso, Gianni1 aDeSimone, Antonio1 aMora, Maria Giovanna1 aMorini, Massimiliano  uhttp://hdl.handle.net/1963/1965