Soft Active Mechanics
This page gives a preview of the research on SOFT ACTIVE MECHANICS I am carrying on. For more information, feel free to check the publications page and/or to contact me!
Dehydration dynamics in polymer gels with cavities
De-hydration induced mechanical instabilities in active elastic spherical shells
Abstract. Active elastic instabilities are common phenomena in the natural world, where they have the character of sudden mechanical morphings. Frequently, the driving force of the instability mechanisms has a chemo-mechanical nature, which makes the instabilities very different from the standard elastic instabilities. In this paper, we describe and study the active elastic instability occurring in a swollen spherical closed shell, confining a water-filled cavity,during a dehydration process. We set up a few numerical experiments based on a stress-diffusion model to give an insight into the phenomenon. Then, we present a study that looks at the chemo-mechanical problem and, through a few simplifying assumptions, allows us to derive a semi-analytical model of the phenomenon. It takes into account both the stress state and the water concentration in the walls of the shell at the onset of the instability. Moreover, it considers the invariance of the cavity volume at the onset of instability, which is due to the impossibility of instantaneously changing the cavity volume filled with water. Eventually, it is shown that the semi- analytic model matches very well the outcomes of the numerical experiments far from the initial regime; the ranges of validity of the approximated analytical model are also discussed.
M. Curatolo, G. Napoli, P. Nardinocchi, S. Turzi. Proc. R. Soc. A 477:20210243.
Other publications on the same topics are:
Modeling solvent dynamics in polymers with solvent-filled cavities. M. Curatolo, P. Nardinocchi, L. Teresi. Mechanics of Soft Materials 2(13), 2020.
Driving water cavitation in a hydrogel cavity. M. Curatolo, P. Nardinocchi, L. Teresi. Soft Matter 14, 2018.
Fiber reorientation in soft inelastic materials
Passive and active fiber reorientation in anisotropic materials
Abstract. We present a continuum model to describe the reorientation of an anisotropic material structure, characterized by two fiber families able to modify their orientations following different evolution dynamics. The evolution equations are derived in a thermodynamically consistent way, and passive and active contributions to the reorientation process are identified. It is shown that a weaker extension of a well-known coaxiality result holds. The transversely isotropic and orthotropic cases are then recovered by imposing the proper constraint on the fiber rotation. Applications to biological experiments on cell layers under stretch are discussed, showing a good agreement between the model and the experimental results. Even though we focus on cell layers, our framework remains general and may be employed to describe reorientation in engineering materials.
J. Ciambella, G. Lucci, P. Nardinocchi, L. Preziosi. International Journal of Engineering Science 176, 2022.Other publications on the same topics are:
Non-affine fiber reorientation in finite inelasticity. J. Ciambella, P. Nardinocchi, Journal of Elasticity, Published on line: 28 October 2022.
A structurally frame-indifferent model for anisotropic visco-hyperelastic materials. J. Ciambella, P. Nardinocchi, Journal of the Mechanica and Physics of Solids 147, 2021.
Torque induced reorientation in active fiber-reinforced materials. J. Ciambella, P. Nardinocchi, Soft Matter 15, 2019.
Magneto-induced remodeling of fibre-reinforced elastomers. r with solvent-filled cavities. J. Ciambella, P. Nardinocchi, International Journal of Non-Linear Mechanics 117, 2019.
Morphing of soft structures
Morphing of soft tubes by anisotropic growth
Abstract. We present a study of smart growth in layered cylindrical structures. We start from the characterization of a compatible growth field in an anisotropic growing tube with the aim to show a small perturbation in the compatible growth field that may produce a controlled deprivation of compatibility and localization of elastic energy storage in a composite structure made up of anisotropic growing tubes.
P. Nardinocchi, L. Teresi. Acta Mechanica 2021 https://doi.org/10.1007/s00707-021-03065-7.Other publications on the same topics are:
Shape-shifting of polymer beams and shells due to oil extraction. D. Battista, V. Luchnikov, P. Nardinocchi, Extreme Mechanics Letters 36, 2020.