research
Analytical Models for Fatigue Life Prediction of Metals in the Stress-Life Approach -- phd thesis by Pietro D’Antuono
dear collegues
I'd be very grateful if you could have a look, if not a deep reading, at the phd thesis of my last student, playing on classical results on uniaxial fatigue, but with a view of simple, unified perspective on constant and varying amplitude fatigue. We made large use of e-fatigue.com web site and the data in there.
Thanks in advance for any remark. The final thesis will be submitted in few weeks time.
Drastic swelling-induced softening of polymer networks with non-covalent cross-linking bonds
Our recent work introduces a microscopically motivated model for the swelling response of polymer networks with non-covalent cross-linking bonds.
As opposed to the classical theories of rubber, we show that the uptake of water in polymer networks comprising hydrogen cross-linking bonds can lead to the dissociation of cross-links. This phenomenon leads to a reduction in the chain-density, an increase in entropy, and a decrease in the free energy. As a result, the network experiences significant softening and exhibits a different mechanical response.
Contact stiffness of rough surfaces
Contact stiffness of multiscale surfaces by truncation analysis
In this concise piece of work, an effective method is shown to gain new understandings into the role of surface structure in the field of contact mechanics. In particular, normal contact stiffness is correlated to parameters of surfaces' fractal dimension and amplitude.
3D printing of simulated geomaterials
https://doi.org/10.1680/jgeot.15.P.034
This work, dating back to 2015 demonstrates the simulation of grain morphologies for subsequent fabrication of surrogate geomaterials
Abstract
Curvature suppresses tensile wrinkles
Transverse wrinkles usually occur in a uniaxially tensile elastic membrane and will be smoothed upon excess stretching. This instability-restabilization response (isola-center bifurcation) can originate from the nonlinear competition between stretching energy and bending energy. Here, we find a crucial factor, the curvature, which can control effectively and precisely the wrinkling and smoothing regimes. When the sheet is bent, the regime of wrinkling amplitude versus membrane elongation is narrowed, with local wrinkling instability coupled with global bending.
