Capacitor-Integrated Triboelectric Nanogenerator Based on Metal-Metal Contact for Current Amplification

2018 ◽  
Vol 8 (15) ◽  
pp. 1703024 ◽  
Author(s):  
Jihoon Chung ◽  
Hyungseok Yong ◽  
Haksung Moon ◽  
Seung Tae Choi ◽  
Divij Bhatia ◽  
...  
Keyword(s):  
Metal Contact ◽  
Triboelectric Nanogenerator ◽  
Metal Metal ◽  
Current Amplification

Improvement of Leak Tightness Analysis of Bolted Closure Systems in Pressure Equipment

2012 ◽  
Author(s):  
F. Billon ◽  
G. Batmale ◽  
B. Drevon
Keyword(s):  
3D Model ◽  
Selection Criterion ◽  
Element Model ◽  
Metal Contact ◽  
Closure Systems ◽  
Metal Metal ◽  
Non Linear ◽  
Dimensional Finite Element ◽  
History Of ◽  
Leak Tightness

The aim of this work is to study the Leak Tightness of the closure systems of nuclear pressure equipment during all situations including in-service operating, emergency and accidental conditions. The analysis is performed using a complete 3-dimensional finite element model of the closure system including : the studs, the gasket, the contacts between the gasket and their seating surfaces (contact elements), the nuts, the cover, the part of the shell on which the opening is located and the tightening preload of the studs. It comprises 2 main phases: (a) Using the 3D model, with non linear internal parameters converted in appropriate linear that allows performing linear analyses, we select, with respect to leaktightness, the most critical thermal and pressure transient among a large amount of transient. This selected transient presents the weakest compressing force between the gasket and its seating surfaces, which is the selection criterion. (b) Then, using the 3D model we perform a full non-linear analysis of the selected transient, taking into account the non linearity of the contacts as well as the non linearity of the gaskets and the tightening preload of the studs. Thus for this transient, we obtain the history of the compressive forces on the gasket and particularly the history of the metal-metal contact for the gaskets multi-ring type (metallic-graphite-metallic) and we can check if compressive forces remain effective. An important consequence is the re-calculation of the tightening preload applied to the studs if the intensity of the metal-metal contact is not sufficient.

Dielectric liquid-based self-operating switch triboelectric nanogenerator for current amplification via regulating air breakdown

Nano Energy ◽  
2021 ◽  
pp. 106292
Author(s):  
Jihoon Chung ◽  
Seh-Hoon Chung ◽  
Zong-Hong Lin ◽  
Youngho Jin ◽  
Jinkee Hong ◽  
...  
Keyword(s):  
Dielectric Liquid ◽  
Triboelectric Nanogenerator ◽  
Current Amplification ◽  
Air Breakdown

The Grinding of Workpiece Materials Exhibiting High Adhesion. Part 2: Forces

1981 ◽  
Vol 103 (2) ◽  
pp. 156-164 ◽  
Author(s):  
S. Yossifon ◽  
C. Rubenstein
Keyword(s):  
Surface Area ◽  
Large Scale ◽  
Metal Contact ◽  
Wheel Surface ◽  
Workpiece Material ◽  
Large Measure ◽  
Scale Adhesion ◽  
High Adhesion ◽  
Metal Metal ◽  
Force Components

Equations expressing the dependence of the force components on grinding parameters and on the fraction of the wheel surface area over which workpiece material adheres during the grinding of workpiece materials which exhibit high adhesion are derived. These are shown to express the experimentally observed relations between the force components for each of the three grinding mechanisms which occur when this class of workpiece is ground. When large scale adhesion of workpiece material to the wheel surface occurs and more than five percent of the wheel surface is occupied by transferred material, the force components arise in large measure as a result of the forces generated through this metal/metal contact.

Physics-based integrated vehicle health management system for predicting the remaining useful life of an aircraft planetary gear transmission

2017 ◽  
Vol 8 (4) ◽  
pp. 484-495 ◽  
Author(s):  
Adrian Cubillo ◽  
Jeroen Vermeulen ◽  
Marcos Rodriguez de la Peña ◽  
Ignacio Collantes Casanova ◽  
Suresh Perinpanayagam
Keyword(s):  
Real Time ◽  
Management System ◽  
Health Management ◽  
Remaining Useful Life ◽  
Metal Contact ◽  
Content Type ◽  
Metal Metal ◽  
Useful Life ◽  
Aircraft System ◽  
Planetary Transmission

Purpose Integrated vehicle health management has been developed for several years in different industries, to be able to provide the required inputs to determine the optimal maintenance operations depending on the actual health status of the system. The purpose of this paper is to demonstrate the potential of a physics-based model (PbM) for prognostics with a real case study, based on the detection of incipient faults and estimate the remaining useful life of a planetary transmission of an aircraft system. Design/methodology/approach Most of the research in the area of health assessment algorithms has been focused on data-driven approaches that are not based on the knowledge of the physics of the system, while PbM approaches rely on the understanding of the system and the degradation mechanisms. A physics-based modelling approach to represent metal-metal contact and fatigue in the gears of the planetary transmission of an aircraft system is applied. Findings Both the failure mode caused by metal-metal contact as caused by fatigue in the gears is described. Furthermore, the real-time application that retrieves the results from the simulations to assess the health of the system is described. Finally the decision making that can be executed during flight in the aircraft is incorporated. Originality/value The paper proposes an innovative prognostics health management system that assesses two important failure modes of the planetary transmission that regulates the speed of the generators of an aircraft. The results from the models have been integrated in an application that emulates a real system in the aircraft and computes the remaining useful life in real time.

Deterministic Model for Rubber-Metal Contact Including the Interaction Between Asperities

2005 ◽  
Author(s):  
E. L. Deladi ◽  
M. B. de Rooij ◽  
D. J. Schipper
Keyword(s):  
Present Model ◽  
Large Deformations ◽  
Deterministic Model ◽  
Bulk Material ◽  
Viscoelastic Behavior ◽  
Local Maximum ◽  
Metal Contact ◽  
Metal Metal ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic

Rubber-metal contact involves relatively large deformations and large real contact areas compared to metal-metal contact. Here, a deterministic model is proposed for the contact between rubber and metal surfaces, which takes into account the interaction between neighboring asperities. In this model, a description of the actual micro-contact is used instead of a summit which is a local maximum at the surface. Linear viscoelastic behavior, modeled by a three-element mechanical model, is assumed for the rubber. In the present model, the equations regarding the deformation due to a Hertzian pressure inside and outside the contact area have been modified for the viscoelastic case. The deterministic case is compared with the statistical one. Besides this, the deformation of the bulk material beneath the asperities is taken into account. The results reveal that the bulk deformation has a significant effect at higher nominal pressures.

scholarly journals Simulation of journal bearing friction in severe mixed lubrication – Validation and effect of surface smoothing due to running-in

2020 ◽  
Author(s):  
David E Sander ◽  
Hannes Allmaier ◽  
Hans Herwig Priebsch
Keyword(s):  
Friction Torque ◽  
Metal Contact ◽  
Solid Base ◽  
Simulation Approach ◽  
Friction Behavior ◽  
Operation Conditions ◽  
Wide Range ◽  
Metal Metal ◽  
Stribeck Curves ◽  
Effect Of Surface

This paper focuses on the friction behavior of jour-nal bearings operating from hydrodynamic to mixedlubrication regime where severe metal-metal contactoccurs. Therefore, friction tests with two differentstatic loads are carried out on the journal bear-ing test-rig from KS Gleitlager. The test resultsin form of Stribeck curves provide a solid base toproof the isothermal elastohydrodynamic simulationapproach. The simulation approach solves the av-eraged Reynolds equation introduced by Patir andCheng and considers metal-metal contact by usingthe Greenwood and Tripp contact model. All nec-essary surface parameters are derived from surfacescans. No less essential in this approach are theexperimentally identified lubricant properties underhigh pressure and high shear rate.The calculated friction torque matches the mea-surement results within the measurement uncertaintyfor a wide range of operation conditions. With thevalidated simulation approach the influence of surfacesmoothing due to metal-metal contact is discussed.Additionally, the limits of a constant boundary coef-ficient are identified and the effects of flow factors arepresented.

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