About

Nicolas Triantafyllidis is a Professor Emeritus in the Department of Mechanical Engineering at the University of Michigan. His contact information includes an email address and a phone number, and he is associated with the G.G. Brown Laboratory in Ann Arbor, MI. His academic and professional focus is within the field of Mechanical Engineering, and he holds the title of Professor Emeritus, indicating a distinguished career in teaching and research in this discipline.

Research topics

• Physics
• Mathematics
• Mechanics
• Thermodynamics
• Materials science

Selected publications

• Step meandering during epitaxial growth

  Journal of the Mechanics and Physics of Solids · 2025-10-03

  articleSenior authorCorresponding
  PublisherDOI

• Forces in interacting ferromagnetic conductors subjected to electrical currents and magnetic fields

  Proceedings of the Royal Society A Mathematical Physical and Engineering Sciences · 2024-06-01 · 1 citations

  articleSenior authorCorresponding

  We revisit the classical problem of Lorentz forces exerted on conductors subjected simultaneously to electrical currents and external magnetic fields within the framework of magnetostatics, i.e. when all field quantities are time-independent. In contrast to the well-known results pertaining to non-magnetic materials, we consider here ferromagnetic materials and study the influence of the magnetic constitutive law on the forces exerted on these conductors. Following the general setting for the coupled magnetoelastic boundary value problem in three dimensions (Lagrangian and Eulerian descriptions), we restrict attention to the two-dimensional problem of a single, two or many interacting parallel conductors of infinite extent and circular sections. Both analytical and numerical (FEM) results are presented. For a single conductor, where the magnetic properties do not influence the force exerted, we calculate the magnetization and magnetic stress fields; analytically for the linear magnetic response and numerically for the general nonlinear case with saturation. For two parallel conductors, the magnetic properties affect significantly the Lorentz forces when the conductors are placed close to each other, as the magnetic fields outside them are strongly influenced by the conductors’ magnetic response. For the case of an infinite array of parallel conductors, there is no influence of their magnetic properties on the Lorentz forces when same direction currents are applied, while only a small magnetic effect is found for currents applied in alternating directions, even for closely spaced conductors.

  PublisherDOI

• The importance of a full chemo-poro-mechanical coupling for the modeling of subcutaneous injections

  Journal of the Mechanics and Physics of Solids · 2024-08-28 · 1 citations

  articleSenior authorCorresponding
  PublisherDOI

• Mechanical Response of Metal Solenoids Subjected to Electric Currents

  Journal of Elasticity · 2023-04-25

  articleSenior authorCorresponding
  PublisherDOI

• The Role of the Relative Fluid Velocity in an Objective Continuum Theory of Finite Strain Poroelasticity

  Journal of Elasticity · 2022-06-08 · 6 citations

  articleOpen accessSenior author
  PublisherOA PDFDOI

• Stability and Localization of Deformation Delay in Finitely Strained Plates at Arbitrary Strain-Rates

  Journal of Elasticity · 2022-12-21 · 2 citations

  articleSenior author
  PublisherDOI

• Multiphysics simulation of electric motors with an application to stators

  International Journal of Solids and Structures · 2022-01-11 · 7 citations

  articleOpen accessSenior authorCorresponding
  PublisherOA PDFDOI

• Nucleation of creases and folds in hyperelastic solids is not a local bifurcation

  Journal of the Mechanics and Physics of Solids · 2022 · 15 citations

  Senior authorCorresponding
  • Materials science
  • Mechanics
  • Mathematics
  PublisherOA PDFDOI

• A coupled electromagnetic–thermomechanical approach for the modeling of electric motors

  Journal of the Mechanics and Physics of Solids · 2021-01-20 · 17 citations

  articleOpen accessSenior authorCorresponding
  PublisherOA PDFDOI

• Scaling laws for step bunching on vicinal surfaces: the role of the dynamical and chemical effects

  arXiv (Cornell University) · 2021-04-28 · 8 citations

  articleOpen accessSenior author

  We study the evolution of step bunches on vicinal surfaces using a thermodynamically consistent step-flow model that (i) circumvents the quasistatic approximation that prevails in the literature by accounting for the dynamics of adatom diffusion on terraces and attachment-detachment at steps (referred to as the dynamical effect), and (ii) generalizes the expression of the step chemical potential by incorporating the necessary coupling between the diffusion fields on adjacent terraces (referred to as the chemical effect). Having previously shown that these effects can explain the onset of step bunching without recourse to the inverse Ehrlich-Schwoebel (iES) barrier or other extraneous mechanisms, we are here interested in the evolution of step bunches beyond the linear-stability regime. In particular, the numerical resolution of the step-flow problem yields a robust power-law coarsening of the surface profile, with the bunch height growing in time as $H\sim t^{1/2}$ and the minimal interstep distance as a function of the number of steps in the bunch cell obeying $\ell_{min}\sim N^{-2/3}$. Although these exponents have previously been reported, this is the first time such scaling laws are obtained in the absence of an iES barrier or adatom electromigration. In order to validate our simulations, we take the continuum limit of the discrete step-flow system, leading to a novel nonlinear evolution equation for the surface height. We investigate the existence of self-similar solutions of this equation and confirm the 1/2 coarsening exponent obtained numerically for $H$. We highlight the influence of the combined dynamical-chemical effect and show that it can be interpreted as an effective iES barrier in the standard BCF theory. Finally, we use a Pad\'e approximant to derive an analytical expression for the velocity of steadily moving step bunches and compare it to numerical simulations.

  PublisherOA PDFDOI

Recent grants

• Thermomechanical Instabilities in M-Lattices with Application to Shape Memory Materials

  NSF · $350k · 2004–2008

• Collaborative Research: Fundamental Experimental and Theoretical Investigation of Finite Strain and High Strain-Rate Electromagnetic Loading Processes in Metals

  NSF · $275k · 2009–2014

• GOALI: Theoretical and Experimental Investigation of Electromagnetically Formed Aluminum

  NSF · $222k · 2004–2007

Frequent coauthors

• Laurent Guin

  Centre National de la Recherche Scientifique

  65 shared

• Kostas Danas

  40 shared

• Michel Jabbour

  36 shared

• Ryan S. Elliott

  26 shared

• Éric Charkaluk

  École Polytechnique

  22 shared

• Michel E. Jabbour

  Centre National de la Recherche Scientifique

  21 shared

• Léopold Shaabani-Ardali

  Laboratoire d'Hydrodynamique

  18 shared

• Guilin Wen

  17 shared

Education

• PhD

  Brown University

  1980