The impact of semimetal nanoparticles on the conduction of thick glass layer at Ag/Si contact interface

2020 ◽  
Vol 127 (22) ◽  
pp. 225302 ◽  
Author(s):  
Keming Ren ◽  
Dan Han ◽  
Tang Ye ◽  
Yong Zhang ◽  
Abasifreke Ebong
Keyword(s):  
Glass Layer ◽  
Contact Interface ◽  
The Impact ◽  
Thick Glass

scholarly journals A Multi-Scale Approach for Nonlinear Dynamic Response Predictions With Fretting Wear

2016 ◽  
Author(s):  
J. Armand ◽  
L. Pesaresi ◽  
L. Salles ◽  
C. W. Schwingshackl
Keyword(s):  
Dynamic Response ◽  
Nonlinear Dynamic ◽  
Accurate Prediction ◽  
Fretting Wear ◽  
Contact Interface ◽  
Contact Conditions ◽  
Nonlinear Dynamic Response ◽  
Multi Scale ◽  
Highly Nonlinear ◽  
The Impact

Accurate prediction of the vibration response of aircraft engine assemblies is of great importance when estimating both the performance and the lifetime of its individual components. In the case of underplatform dampers, for example, the motion at the frictional interfaces can lead to a highly nonlinear dynamic response and cause fretting wear at the contact. The latter will change the contact conditions of the interface and consequently impact the nonlinear dynamic response of the entire assembly. Accurate prediction of the nonlinear dynamic response over the lifetime of the assembly must include the impact of fretting wear. A multi-scale approach that incorporates wear into the nonlinear dynamic analysis is proposed, and its viability is demonstrated for an underplatform damper system. The nonlinear dynamic response is calculated with a multiharmonic balance approach, and a newly developed semi-analytical contact solver is used to obtain the contact conditions at the blade-damper interface with high accuracy and low computational cost. The calculated contact conditions are used in combination with the energy wear approach to compute the fretting wear at the contact interface. The nonlinear dynamic model of the blade-damper system is then updated with the worn profile and its dynamic response is recomputed. A significant impact of fretting wear on the nonlinear dynamic behaviour of the blade-damper system was observed, highlighting the sensitivity of the nonlinear dynamic response to changes at the contact interface. The computational speed and robustness of the adopted multi-scale approach are demonstrated.

scholarly journals A Multiscale Approach for Nonlinear Dynamic Response Predictions With Fretting Wear

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
J. Armand ◽  
L. Pesaresi ◽  
L. Salles ◽  
C. W. Schwingshackl
Keyword(s):  
Dynamic Response ◽  
Nonlinear Dynamic ◽  
Accurate Prediction ◽  
Fretting Wear ◽  
Multiscale Approach ◽  
Contact Interface ◽  
Contact Conditions ◽  
Nonlinear Dynamic Response ◽  
Highly Nonlinear ◽  
The Impact

Accurate prediction of the vibration response of aircraft engine assemblies is of great importance when estimating both the performance and the lifetime of their individual components. In the case of underplatform dampers, for example, the motion at the frictional interfaces can lead to a highly nonlinear dynamic response and cause fretting wear at the contact. The latter will change the contact conditions of the interface and consequently impact the nonlinear dynamic response of the entire assembly. Accurate prediction of the nonlinear dynamic response over the lifetime of the assembly must include the impact of fretting wear. A multiscale approach that incorporates wear into the nonlinear dynamic analysis is proposed, and its viability is demonstrated for an underplatform damper system. The nonlinear dynamic response is calculated with a multiharmonic balance approach, and a newly developed semi-analytical contact solver is used to obtain the contact conditions at the blade–damper interface with high accuracy and low computational cost. The calculated contact conditions are used in combination with the energy wear approach to compute the fretting wear at the contact interface. The nonlinear dynamic model of the blade–damper system is then updated with the worn profile and its dynamic response is recomputed. A significant impact of fretting wear on the nonlinear dynamic behavior of the blade–damper system was observed, highlighting the sensitivity of the nonlinear dynamic response to changes at the contact interface. The computational speed and robustness of the adopted multiscale approach are demonstrated.

scholarly journals A modelling approach for the nonlinear dynamics of assembled structures undergoing fretting wear

2019 ◽  
Vol 475 (2223) ◽  
pp. 20180731 ◽  
Author(s):  
J. Armand ◽  
L. Pesaresi ◽  
L. Salles ◽  
C. Wong ◽  
C. W. Schwingshackl
Keyword(s):  
Nonlinear Dynamics ◽  
Dynamic Analysis ◽  
Contact Stiffness ◽  
Fretting Wear ◽  
Real Contact Area ◽  
Nonlinear Phenomena ◽  
Contact Interface ◽  
Computationally Efficient ◽  
The Impact ◽  
Modelling Approach

Assembled structures tend to exhibit nonlinear dynamic behaviour at high excitation levels due to the presence of contact interfaces. The possibility of building predictive models relies on the ability of the modelling strategy to capture the complex nonlinear phenomena occurring at the interface. One of these phenomena, normally neglected, is the fretting wear occurring at the frictional interface. In this paper, a computationally efficient modelling approach which enables considerations of the effect of fretting wear on the nonlinear dynamics is presented. A multi-scale strategy is proposed, in which two different time scales and space scales are used for the contact analysis and dynamic analysis. Thanks to the de-coupling of the contact and dynamic analysis, a more realistic representation of the contact interface, which includes surface roughness, is possible. The proposed approach is applied to a single bolted joint resonator with a simulated rough contact interface. A tendency towards an increase of real contact area and contact stiffness at the interface is clearly observed. The dynamic response of the system is shown to evolve over time, with a slight decrease of damping and an increase of resonance frequency, highlighting the impact of fretting wear on the system dynamics.

A Critique on “Measurement of the Hygric Resistance of Concrete Blocks with Perfect Contact Interface: Influence of the Contact Area”

2021 ◽  
Vol 15 (1) ◽  
pp. 330-338
Author(s):  
Hans Janssen
Keyword(s):  
Contact Area ◽  
Moisture Absorption ◽  
Capillary Absorption ◽  
Identification Algorithm ◽  
Contact Interface ◽  
Knee Point ◽  
Concrete Blocks ◽  
Perfect Contact ◽  
The Impact ◽  
Absorption Measurements

Background: In March 2021, this journal published the article “Measurement of the hygric resistance of concrete blocks with perfect contact interface: influence of the contact area”. That article reports on a study on the impact of ‘perfect contact’ between concrete blocks on moisture absorption, with a focus on the impact of the sample cross-section. Objective: This critique aims at formulating several essential concerns on the hygric aspects of that article, thus expressing the discusser’s reservations on the reliability of the presented outcomes in particular and the published article in general. Methods: The data, as provided in the graphs of the critiqued article, are digitally extracted and further analysed by the discusser. Results: That analysis results in serious concerns with regard to 1) the magnitude of the quantified post-interface flows, 2) the distinguishability of the moisture absorption in the monolithic and perfect contact samples, 3) the robustness of the knee-point identification algorithm, 4) the dependability of the capillary absorption measurements, and 5) the consistency of the capillary absorption processing. These are finally translated into 8 concrete questions to be addressed by the authors of the critiqued article in order to placate these doubts and establish the reliability of their work. Conclusion: This critique formulates appreciable apprehension with respect to an earlier publication in the journal and invites its authors to respond to that via answering the 8 concrete questions. If not satisfactory, then the critiqued article’s findings cannot be considered reliable, and the journal should reconsider its prior publication.

Improving Impact Properties of Fiber/Metal Laminates by Using Suitable Layer Arrangement According to Different Standard Test Methods

2009 ◽  
Author(s):  
M. Sadighi ◽  
S. Dariushi
Keyword(s):  
Hybrid Composites ◽  
Test Methods ◽  
Standard Test ◽  
Thin Layers ◽  
Glass Layer ◽  
Fiber Metal Laminates ◽  
Zero Degree ◽  
Fiber Metal ◽  
The Impact ◽  
Better Than

Fiber metal laminates (FMLs) are hybrid composites consisting of alternating thin layers of metal sheets and fiber adhesive layers. This paper describes an experimental investigation of the impact energy absorption capability of glass fiber/aluminum laminates in relation to stacking sequence. Six groups of specimens were studied. Each unsymmetrical group consisted of two specimens with exactly similar layers but in different positions. Changing the arrangement of layers does not change the cost or weight but improve the properties considerably. Test results show that using 45° glass layer at the front (where the striker impacts) is better than 90° glass layer and using 90° glass layer at the front is better than zero degree layer. The best arrangement is 45° glass layer at the front and zero degree glass layer at the back.

The Role of Nano-crystallites on Conduction Mechanisms of Current Through Ag Gridlines of Si Solar Cells

MRS Advances ◽  
2019 ◽  
Vol 4 (5-6) ◽  
pp. 311-318 ◽  
Author(s):  
Keming Ren ◽  
Tang Ye ◽  
Yong Zhang ◽  
Abasifreke Ebong
Keyword(s):  
Solar Cells ◽  
Fill Factor ◽  
Glass Layer ◽  
Transport Mechanisms ◽  
Raman Spectrometry ◽  
Si Solar Cells ◽  
Ag Crystallites ◽  
The One ◽  
The Impact

ABSTRACTIn order to understand the impact of nano-crystallites on current transport mechanisms in screen-printed c-Si solar cells with lowly-doped emitter, Te-glass based Ag pastes with different transition temperatures (Tg) were used. The Te-glass with lower Tg showed lower Rc than the one with higher Tg due to the formation of nano-crystallites in the glass layer. These nano-crystallites enhance the conductivity of the glass and lead to higher fill factor (FF). The nature of these nano-crystallites was first identified by the Raman spectrometry and the peaks at 76 cm-1, 119 cm-1 and 145 cm-1 were corresponding to Ag2Te and PbTe. The conductive-AFM further confirmed the high conductivity of these nano-crystallites without pyramidal Ag crystallites, which means the current transporting from Si emitter to Ag gridlines is mainly through the nano-crystallites in the glass.

Spectral, Radiation-Optical and Shielding Properties of Phosphate Glasses with High Lead Content

2008 ◽  
Vol 39-40 ◽  
pp. 213-218 ◽  
Author(s):  
Valerii I. Arbuzov ◽  
Yurii K. Fyodorov
Keyword(s):  
Radiation Shielding ◽  
Phosphate Glasses ◽  
Lead Content ◽  
Glass Layer ◽  
Similar Data ◽  
Spectral Radiation ◽  
Radiation Resistant ◽  
Shielding Properties ◽  
High Lead ◽  
Thick Glass

Spectral, radiation optical, and radiation shielding properties of new phosphate glasses, TPF, with high lead content (up to 40 mol. % PbO) were studied. They are characterized by the heightened radiation optical resistance at exposure doses up to 5*107 R, and by the improved radiation shielding properties as compared with similar data of silicate glasses with the same lead content. A TPF boundary of semi-transmission for a 1 cm thick glass layer lies approximately at 355 nm, its absorption coefficient, µ, for γ-quanta of 137Cs (0.663 MeV) and 60Co (1.25 MeV) reach 0.373 and 0.240 cm-1 whereas µ’s of the Russian radiation resistant strong flint TF110 (40 mol. % PbO) are equal to 0.355 and 0.214 cm-1. These properties allowed to use TPF instead of strong silicate flints as material for observation radiation schielding windows of facilities of special usage.

Bounday-Layer Asymptotics on the Contact Interface in the Impact Problem

2012 ◽  
Vol 446-449 ◽  
pp. 3787-3790
Author(s):  
Lei Hou ◽  
Bin Wang ◽  
De Zhi Lin ◽  
Lin Qiu ◽  
Yu He Ren
Keyword(s):  
Contact Interface ◽  
The Impact ◽  
Impact Problem

Bounday-Layer Asymptotics on the Contact Interface in the Impact Problem

2012 ◽  
Vol 446-449 ◽  
pp. 3787-3790
Author(s):  
Lei Hou ◽  
Bin Wang ◽  
De Zhi Lin ◽  
Lin Qiu ◽  
Yu He Ren
Keyword(s):  
Boundary Layer ◽  
Numerical Results ◽  
Contact Boundary ◽  
Contact Interface ◽  
Element Analysis ◽  
Contact Conditions ◽  
Numerical Result ◽  
Layer Analysis ◽  
Adi Iteration ◽  
The Impact

The information of boundary condition in the contact interface reflected complex properties of visco-elastic material with various contact conditions. Numerical results and the asymptotic estimates were calculated. It is presented by the software which are consistent with the boundary-layer analysis in our previous papers. In this paper, the application of computer simulating and related numerical result on the contact boundary-layer has been discussed. Numerical results were calculated (by using HPC platform, NAG toolbox for Matlab) and shown by use of the software i.e. LS-DYNA. The numerical scheme yields the convergent finite element analysis (FEA) solution and stable semi-discrete Galerkin-ADI (G-ADI) iteration.

Optical properties of silicates co-doped with Si and Er3+ ions

2004 ◽  
Vol 832 ◽  
Author(s):  
Y. Lebour ◽  
P. Pellegrino ◽  
J. A. Moreno ◽  
C. Garcia ◽  
B. Garrido ◽  
...  
Keyword(s):  
Excitation Cross Section ◽  
Soda Lime ◽  
Fused Silica ◽  
Glass Layer ◽  
Pure Silica ◽  
Si Nanoparticles ◽  
Aluminium Silicates ◽  
Effective Excitation ◽  
Thick Glass ◽  
Similar Intensity

ABSTRACTWe have characterized the mechanism of energy transfer from Si nanoparticles to Er3+ ions in different silicate glasses, namely soda-lime and aluminium silicates, and made the comparison with pure silica. By means of a multi-implantation scheme we have formed a 350 nm thick glass layer with a uniform Si excess (5% or 15% atomic excess) and an Er distribution. Several Er doses were chosen so that the resulting Er peak concentration could vary from 2 × 1019 up to 6 × 1020 cm−3. Fused silica wafers coimplanted in the same conditions were used as a reference material in order to compare the different efficiency and mechanisms of Er emission as a function of the host silicate composition. Thermal treatment at low temperature has been performed to enhance the photoluminescence around 1540 nm. Large PL emission, compared to structures doped only with Er, has been successfully detected in all co-implanted glasses, with similar intensity. Moreover, we have measured PL lifetimes from 2.5 to 12 ms (depending on the Er dose and Si excess), and estimated an Er effective excitation cross-section of the order of 1 × 10−17 cm2.

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