Publications related to Principal curvature

Short-term behavior of glass fiber-polymer composite bending-active elastica beam under service load application

Thomas Keller, Tara Habibi, Landolf-Giosef-Anastasios Rhode-Barbarigos

Bending-active elastica beam is a structural configuration that is based on the elastic deformation of an initially straight beam. This deformation occurs when horizontal displacements are applied to a sliding support, causing the beam to bend into an arch ...

2024

Indentation and stability of woven domes

Pedro Miguel Nunes Pereira de Almeida Reis, Célestin Vallat, Tian Chen, Tomohiko Sano, Samuel Jean Bernard Poincloux

Discrete domes are doubly curved structures comprising a network of beam-like elements. We study the mechanics of discrete domes made of ribbons woven in a pentagonal triaxial pattern. Experiments and finite element simulations are performed to characteriz ...

ELSEVIER2023

In-situ atomic level observation of the strain response of graphene lattice

Klaus Kern, Jz -Yuan Juo

Strain is inevitable in two-dimensional (2D) materials, regardless of whether the film is suspended or supported. However, the direct measurement of strain response at the atomic scale is challenging due to the difficulties of maintaining both flexibility ...

Nature Portfolio2023

How Lagrangian States Evolve Into Random Waves

Alejandro Rivera

In this paper, we consider a compact connected manifold (X, g) of negative curvature, and a family of semi-classical Lagrangian states f(h)(x) = a(x)e(i phi(x)/h) on X. For a wide family of phases phi, we show that f(h), when evolved by the semi-classical ...

ECOLE POLYTECHNIQUE2022

Determining crack kinematics from imaged crack patterns

Katrin Beyer, Bryan German Pantoja Rosero, Amir Rezaie, Ketson Roberto Maximiano Dos Santos

Determining the relationship between the cause of damage and the subsequent structural behavior of infrastructure systems requires an accurate characterization of the propagation of cracks, which represents the evolution of the damage state. When no inform ...

2022

Nonperturbative Quantum Field Theory in Curved Spacetime

Kamran Salehi Vaziri

Quantum Field Theory(QFT) as one of the most promising frameworks to study high energy and condensed matter physics, has been mostly developed by perturbative methods. However, perturbative methods can only capture a small island of the space of QFTs. QFT ...

EPFL2022

Computational Design of Weingarten Surfaces

Mark Pauly, Davide Pellis

In this paper we study Weingarten surfaces and explore their potential for fabrication-aware design in freeform architecture. Weingarten surfaces are characterized by a functional relation between their principal curvatures that implicitly defines approxim ...

2021

Amphiphilic nanoparticles generate curvature in lipid membranes and shape liposome-liposome interfaces

Francesco Stellacci, Francesca Olgiati

We show by molecular dynamics that amphiphilic Au nanoparticles (NP) with a diameter of 4 nm generate curvature in phosphatidylcholine lipid membranes. NPs generate negative curvature when they adsorb on the membrane surface but, as they get spontaneously ...

ROYAL SOC CHEMISTRY2021

GarNet++: Improving Fast and Accurate Static 3D Cloth Draping by Curvature Loss

Pascal Fua, Mathieu Salzmann, Victor Constantin, Shaifali Parashar, Erhan Gündogdu

In this paper, we tackle the problem of static 3D cloth draping on virtual human bodies. We introduce a two-stream deep network model that produces a visually plausible draping of a template cloth on virtual 3D bodies by extracting features from both the b ...

2022

Adaptive Gradient Descent without Descent

Konstantin Mishchenko

We present a strikingly simple proof that two rules are sufficient to automate gradient descent: 1) don’t increase the stepsize too fast and 2) don’t overstep the local curvature. No need for functional values, no line search, no information about the func ...

2020

Towards a geometry independent traction-separation and angle relation due to large scale bridging in DCB configuration

John Botsis, Georgios Pappas

Traction-separation relations due to large scale bridging in composites are very important in modeling their fracture response. Several works demonstrated that such relations are dependent upon the specimen's stiffness and loading conditions. Experimental ...

ELSEVIER SCI LTD2020

Nonlinear buckling behavior of a complete spherical shell under uniform external pressure and homogenous natural curvature

Matteo Pezzulla

In this work, we consider the stability of a spherical shell under combined loading from a uniform external pressure and a homogenous natural curvature. Nonmechanical stimuli, such as one that tends to modify the rest curvature of an elastic body, are prev ...

AMER PHYSICAL SOC2020

Full field dependence of primary aberrations in perturbed double-plane symmetric systems with a circular pupil

Toralf Scharf, Alessandro Grosso

This paper deals with the theory of primary aberrations for perturbed double-plane symmetric optical systems consisting of a combination of tilted and decentered surfaces and a circular pupil. First, the analytical expressions describing the full field beh ...

OPTICAL SOC AMER2020

Tribological Approach to the Watch Movements

Valentine Agnès Madeleine Magnin

Mechanical watches are complex and sensitive systems that have to maintain a faultless precision over their lifetime. However, this precision can be altered by disturbances occurring during the functioning time, such as friction, lubricant drying, or wear, ...

EPFL2020

Anisotropy and shaping effects on the stability boundaries of infernal ideal MHD modes in tokamak hybrid plasmas

Wilfred Anthony Cooper, Jonathan Graves, Daniele Brunetti

Anisotropy and some limiting toroidal flow effects on the stability of nearly resonant ideal magnetohydrodynamic modes in hybrid shaped tokamak plasmas are investigated within the ideal MHD infernal mode framework. Such effects are found to alter the plasm ...

2020

Extremal Eigenvalues Of The Dirichlet Biharmonic Operator On Rectangles

Davide Buoso

We study the behaviour of extremal eigenvalues of the Dirichlet biharmonic operator over rectangles with a given fixed area. We begin by proving that the principal eigenvalue is minimal for a rectangle for which the ratio between the longest and the shorte ...

2020

Mechanics of a pressure-controlled adhesive membrane for soft robotic gripping on curved surfaces

Jamie Paik, Sukho Song, Metin Sitti

This paper aims at understanding the adhesion mechanics of a pressure-controlled adhesive thin elastomeric membrane for soft robotic gripping on non-planar, curved surfaces. The adhesive elastic membrane is lined with gecko-inspired microfiber arrays and c ...

2019

Chemically etched plastic optical fiber probe for near-field scanning optical microscopy in liquids

Giovanni Dietler, Serguei Sekatski, Anton Smirnov, Kanat Dukenbayev

Some preliminary results and experimental details of Near-field Scanning Optical Microscopy (NSOM) operation in liquids have been reported by us earlier(1-4). Here we present the first use of custom made polystyrene/poly (methyl methacrylate) (PMMA) optica ...

SPIE-INT SOC OPTICAL ENGINEERING2019

Some regularity results for p-harmonic mappings between Riemannian manifolds

Changyu Guo

Let M be a C-2-smooth Riemannian manifold with boundary and N a complete C-2-smooth Riemannian manifold. We show that each stationary p-harmonic mapping u: M -> N, whose image lies in a compact subset of N, is locally C-1,C-alpha for some alpha is an eleme ...

2019

A Gauss-Bonnet Theorem for Asymptotically Conical Manifolds and Manifolds with Conical Singularities

Adrien Giuliano Marcone

The purpose of this thesis is to provide an intrinsic proof of a Gauss-Bonnet-Chern formula for complete Riemannian manifolds with finitely many conical singularities and asymptotically conical ends. A geometric invariant is associated to the link of both ...

EPFL2019