Publications related to Rigid rotor

Design of a Flexure-Based Flywheel for the Storage of Angular Momentum and Kinetic Energy

Simon Nessim Henein, Florent Cosandier, Hubert Pierre-Marie Benoît Schneegans, Patrick Robert Flückiger

The flywheel is a widespread mechanical component used for the storage of kinetic energy and angular momentum. It typically consists of cylindrical inertia rotating about its axis on rolling bearings, which involves undesired friction, lubrication, and wea ...

2024

State of the Art in Dense Monocular Non-Rigid 3D Reconstruction

Pascal Fua

3D reconstruction of deformable (or non-rigid) scenes from a set of monocular 2D image observations is a long-standing and actively researched area of computer vision and graphics. It is an ill-posed inverse problem, since-without additional prior assumpti ...

WILEY2023

Design and experimental investigation of a herringbone grooved gas bearing supported turbocharger

Jürg Alexander Schiffmann, Wanhui Liu

The design of an oil free turbocharger supported on herringbone grooved gas bearing was formulated as a multi-objective problem, which was solved by coupling a reduced order parametric model for gas bearing supported rotors with an evolutionary algorithm. ...

2023

Experimental and numerical investigation of the unbalance behavior of rigid rotors supported by spiral-grooved gas journal bearings

Jürg Alexander Schiffmann, Elia Iseli

The forced response of rigid rotors, supported by herringbone-grooved gas journal bearings are investigated numerically and experimentally. The rotor configurations are varied by using end cylinders, attached at both sides of the shaft. Three rotors with d ...

ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD2022

An elastic rod in frictional contact with a rigid cylinder

Pedro Miguel Nunes Pereira de Almeida Reis, Paul Grandgeorge, Tomohiko Sano

We investigate the load transmission along an elastic rod of finite cross-section in contact with a rigid cylinder, as system often referred to as the generalized capstan problem. In the presence of friction, the idealized classic capstan equation predicts ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Principle and Analysis of Radial-Force-Based Swirling Actuator for Low-Speed High-Torque Applications

Adrien Jean-Michel Thabuis

This article proposes a swirling actuator that uses the electromagnetic radial force and mechanical gears to generate rotational torque. The proposed actuator generates a rotating radial force between an inner stator and a swirler. The gears on the swirler ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

Groove: Flexible Metadata-Private Messaging

Ludovic Barman, David Lazar

Metadata-private messaging designs that scale to support millions of users are rigid: they limit users to a single device that is online all the time and transmits on short regular intervals, and require users to choose precisely when each of their buddies ...

Usenix Assoc2022

State-to-state surface scattering of methane studied by bolometric infrared laser tagging detection

Bo-Jung Chen

State-to-state molecule/surface scattering experiments prepare the incident molecules in a specific quantum state and measure the quantum state distribution of the scattered molecules. The comparison of state resolved experiments with theory can serve as s ...

EPFL2022

Experimental Investigation of Enhanced Grooves for Herringbone Grooved Journal Bearings

Jürg Alexander Schiffmann, Patrick Hubert Wagner, Philipp Kaspar Bättig

This paper presents the results of a theoretical and experimental investigation of the potential of enhanced groove geometries to increase the bearing clearance of a Herringbone Grooved Journal Bearing (HGJB) supported rotor. The theoretical study investig ...

2022

Buoyancy-driven convection of droplets on hot nonwetting surfaces

François Gallaire, Eunok Yim

The global linear stability of a water drop on hot nonwetting surfaces is studied. The droplet is assumed to have a static shape and the surface tension gradient is neglected. First, the nonlinear steady Boussinesq equation is solved to obtain the axisymme ...

AMER PHYSICAL SOC2021

Stability and Unbalance Analysis of Rigid Rotors Supported by Spiral Groove Bearings: Comparison of Different Approaches

Jürg Alexander Schiffmann, Elia Iseli

The dynamic behavior of spiral-grooved gas bearing supported four degrees-of-freedom (DOF) rotors is investigated by means of linearized bearing force coefficients and full time-integrated transient analysis. The transient method consists of a state-space ...

2021

Nonlinear study on a rigid rotor supported by herringbone grooved gas bearings: Theory and validation

Jürg Alexander Schiffmann, Patrick Hubert Wagner, Philipp Kaspar Bättig, Wanhui Liu

The nonlinear behavior of a rigid rotor supported by herringbone grooved journal gas bearings (HGJBs) was investigated in this study. The two-dimensional narrow groove theory (2D-NGT) was adopted to model the HGJBs. A set of integrated rotor-bearing state ...

2021

Rigid foldability and mountain-valley crease assignments of square-twist origami pattern

Huijuan Feng

Rigid foldability allows an origami pattern to fold about crease lines without twisting or stretching component panels. It enables folding of rigid materials, facilitating the design of foldable structures. Recent study shows that rigid foldability is affe ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Topology design of general tensegrity with rigid bodies

Yafeng Wang

This study presents a general approach to the topology design of tensegrities with rigid bodies. To the best of the authors' knowledge, all existing topology design methods of tensegrities focus on tensegrities that only consist of members carrying axial f ...

2020

An Instrumented High-Speed Rotor with Embedded Telemetry for The Continuous Spatial Pressure Profile Measurement in Gas Lubricated Bearings: A Proof of Concept

Jürg Alexander Schiffmann, Karim Magdi Zakaria Abdelrahman Shalash

Pressure is one of the constitutional quantities governing the flow field in gas lubricated bearings. Knowledge of the pressure is of principal importance in the fundamental understanding of such bearings and for the calibration of reduced order models. Th ...

2020

Inkjet Printing of Complex Soft Machines with Densely Integrated Electrostatic Actuators

Herbert Shea, Samuel Rosset, Samuel Schlatter, Giulio Grasso

A multimaterial inkjet printing method for integrated soft multifunctional machines is reported, combining dense arrays of electrostatic actuators, multilayer electrical routing, and complex networks of microfluidic channels in one printing process. Most a ...

2020

Displacement Study of a Large-Scale Freeform Timber Plate Structure Using a Total Station and a Terrestrial Laser Scanner

Yves Weinand, Anh Chi Nguyen

Recent advances in timber construction have led to the realization of complex timber plate structures assembled with wood-wood connections. Although advanced numerical modelling tools have been developed to perform their structural analysis, limited experi ...

2020

On the stabilizing effect of rotation in the 3d Euler equations

Klaus Martin Widmayer

While it is well known that constant rotation induces linear dispersive effects in various fluid models, we study here its effect on long time nonlinear dynamics in the inviscid setting. More precisely, we investigate stability in the 3d rotating Euler equ ...

2020

Molecular motor crossing the frontier of classical to quantum tunneling motion

Harald Brune, Roland Widmer, Jan Prinz, Samuel Thomas Stolz

The reliability by which molecular motor proteins convert undirected energy input into directed motion or transport has inspired the design of innumerable artificial molecular motors. We have realized and investigated an artificial molecular motor applying ...

National Academy of Sciences2020

Shapes of rotating normal fluid He-3 versus superfluid He-4 droplets in molecular beams

Christoph Bostedt, Andre Al Haddad

Previous single-pulse extreme ultraviolet and x-ray coherent diffraction studies revealed that superfluid He-4 droplets obtained in a free jet expansion acquire sizable angular momentum, resulting in significant centrifugal distortion. Similar experiments ...

AMER PHYSICAL SOC2020