scholarly journals Short- to long-term deformation behavior, failure, and service life of amorphous polymers under cyclic torsional and multiaxial loadings

2021 ◽  
pp. 103106
Author(s):  
T. Barriere ◽  
A. Cherouat ◽  
X. Gabrion ◽  
S. Holopainen
Keyword(s):  
Service Life ◽  
Deformation Behavior ◽  
Amorphous Polymers ◽  
Multiaxial Loadings

scholarly journals A Novel Highly Durable Carbon/Silver/Silver Chloride Composite Electrode for High-Definition Transcranial Direct Current Stimulation

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1962
Author(s):  
Lingjun Li ◽  
Guangli Li ◽  
Yuliang Cao ◽  
Yvonne Yanwen Duan
Keyword(s):  
Service Life ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Silver Chloride ◽  
Cycling Performance ◽  
High Definition ◽  
Silver Silver ◽  
Sintered Ag ◽  
Silver Silver Chloride

High-definition transcranial direct current stimulation (HD-tDCS) is a promising non-invasive neuromodulation technique, which has been widely used in the clinical intervention and treatment of neurological or psychiatric disorders. Sintered Ag/AgCl electrode has become a preferred candidate for HD-tDCS, but its service life is very short, especially for long-term anodal stimulation. To address this issue, a novel highly durable conductive carbon/silver/silver chloride composite (C/Ag/AgCl) electrode was fabricated by a facile cold rolling method. The important parameters were systematically optimized, including the conductive enhancer, the particle size of Ag powder, the C:Ag:PTFE ratio, the saline concentration, and the active substance loading. The CNT/Ag/AgCl-721 electrode demonstrated excellent specific capacity and cycling performance. Both constant current anodal polarization and simulated tDCS measurement demonstrated that the service life of the CNT/Ag/AgCl-721 electrodes was 15-16 times of that of sintered Ag/AgCl electrodes. The much longer service life can be attributed to the formation of the three-dimensional interpenetrating conductive network with CNT doping, which can maintain a good conductivity and cycling performance even if excessive non-conductive AgCl is accumulated on the surface during long-term anodal stimulation. Considering their low cost, long service life, and good skin tolerance, the proposed CNT/Ag/AgCl electrodes have shown promising application prospects in HD-tDCS, especially for daily life scenarios.

The Reinforced Concrete Durability and Rebar Erosion Monitoring

2012 ◽  
Vol 446-449 ◽  
pp. 3252-3258
Author(s):  
Jin Yang Zhang ◽  
De Mi Cui ◽  
Lie Min Lv ◽  
Zhi Yang
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Protective Layer ◽  
Concrete Surface ◽  
Monitor System ◽  
Concrete Durability ◽  
Information Feedback ◽  
Starting Time ◽  
Cast Concrete

On the basis of the advantages of low construction cost, remarkable dynamics property, easy cast moulding and more controllable construction, the reinforced concrete construct are widely applied in buildings and main structures of constructions in China. However, the reinforced concrete is found more or less aging after many years’ utilization and erosion from the environment, which will lead to a hidden risk to affect its functions. After technical development for decades, the concrete can assure its durability under normal situation, yet the function would be deteriorated due to the erosion from the complex and harsh environment to make it hardly reach its designed service life. With the assist of CorroWatch erosion monitor system, the concrete structures’ erosion can kept watched on to obtain the depassivation development and information feedback of some key data dynamically and in long term so as to foresee precisely the erosion starting time. The newly cast concrete depassivation frontline is located on concrete surface and will tend to go through the protective layer and penetrate towards rebar as time goes on. Its structure service life can be enhanced with the re-designed durability in terms of the mentioned characters and do well the erosion proof measures.

Applications of Chemiluminescence in Rubber Research

1992 ◽  
Vol 65 (4) ◽  
pp. 736-743 ◽  
Author(s):  
Dan Forsström ◽  
Anna Kron ◽  
Bengt Mattson ◽  
Torbjörn Reitberger ◽  
Bengt Stenberg ◽  
...  
Keyword(s):  
Service Life ◽  
Natural Rubber ◽  
Organic Materials ◽  
Photon Counting ◽  
Cellulose Fiber ◽  
Polymeric Materials ◽  
Sensitive Technique ◽  
Weak Light ◽  
Counting Equipment

Abstract The oxidation of most organic materials is accompanied by the emission of weak light, so called chemiluminescence (CL). This emission has previously often been designated oxyluminescence. CL has been known for several years, but it is not until recently that the development of photon counting equipment has allowed detection of levels down to a few photons per second. This development makes CL a promising nondestructive and extremely sensitive technique to provide data which may be useful to estimate the service life of polymeric materials. Various applications of the CL-method for the detection of oxidation of elastomers are reported: such as, stabilization of hydroxyl-terminated polybutadiene; degradation of latex coating of paper; long-term thermo-oxidation of natural rubber; indication of ultrathin coating of cellulose fiber with polybutadiene.

Long Term Performance of Fusion Bond Epoxy Coated Pipelines

2004 ◽  
Author(s):  
Robert Worthingham ◽  
Matt Cetiner
Keyword(s):  
Service Life ◽  
Cathodic Protection ◽  
Laboratory Tests ◽  
Large Diameter ◽  
Service Temperature ◽  
Line Pipe ◽  
Coating Type ◽  
Long Term Performance ◽  
Term Performance

TransCanada Pipelines has been using fusion bond epoxy (FBE) external coatings for large diameter line pipe since the early 1980’s. Overall, this coating type, when applied in accordance to the CSA Z245.20 standard provides excellent protection and long term service life. However, some reports from the field described the periodic occurrence of blistering and disbondment of the coating. In order to understand the magnitude and causes of these phenomena, an investigative program was initiated. Laboratory tests and a program of field examinations were carried out. Some of the variables considered were: age of the coating; service temperature; cathodic protection (CP) levels; and soil type. No evidence of a pipeline integrity threat associated with fusion bond epoxy deterioration was found at any of the locations examined. Observations and correlations of coating to exposure conditions will be presented.

scholarly journals Methodology of Accelerated Characterization for long-term creep prediction of polymer structures to ensure their service life

2019 ◽  
Vol 79 ◽  
pp. 106050 ◽  
Author(s):  
Eric Lainé ◽  
Claire Bouvy ◽  
Jean-Claude Grandidier ◽  
Geert Vaes
Keyword(s):  
Service Life ◽  
Term Creep

scholarly journals Long-Term Settlement of High Concrete-Face Rockfill Dam by Field Monitoring and Numerical Simulation

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Xinjie Zhou ◽  
Xinjian Sun ◽  
Junxing Zheng ◽  
Haoyuan Jiang ◽  
Yongye Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Creep Deformation ◽  
Deformation Behavior ◽  
Finite Element Software ◽  
Rockfill Materials ◽  
Stress And Deformation ◽  
Long Term Performance ◽  
Term Performance ◽  
Concrete Face

High concrete-face rockfill dams (CFRDs) with heights of over 100 m have been quickly developed in recent years. The self-weight of rockfill materials causes creep deformation of the dam body. However, the creep analysis method of high CFRDs in finite element software is few, and sometimes, it can also not reflect the long-term performance of high CFRDs well. Therefore, it is necessary to carry out the secondary development in finite element software. This study developed a subroutine that can run in Finite Element Method (FEM) platform ABAQUS to simulate long-term creep deformation behavior of the rockfill materials more accurately. Then, a displacement back-analysis for parameters, based on the Xujixia high CFRD project, is performed by the neural network response surface method (BP-MPGA/MPGA). Remarkable agreements are observed between simulation and field monitoring results. The calibrated FEM model is used to predict stress and deformation behavior of the Xujixia high CFRD after three years of operation period. The result indicates that rockfill creep deformation has a significant impact on stress and deformation of the high CFRD during the operation. This research may predict long-term performance using FEM in the design stage for high CFRDs.

scholarly journals Long-Term Performance of Trestle Bridges: Case Study of an Indonesian Marine Port Structure

2020 ◽  
Vol 8 (5) ◽  
pp. 358 ◽  
Author(s):  
Yusak Oktavianus ◽  
Massoud Sofi ◽  
Elisa Lumantarna ◽  
Gideon Kusuma ◽  
Colin Duffield
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Service Life ◽  
Field Measurement ◽  
Field Measurements ◽  
Element Analysis ◽  
Moment Capacity ◽  
Non Destructive

A precast reinforced concrete (RC) T-beam located in seaport Terminal Peti Kemas (TPS) Surabaya built in 1984 is used as a case study to test the accuracy of non-destructive test techniques against more traditional bridge evaluation tools. This bridge is mainly used to connect the berth in Lamong gulf and the port in Java Island for the logistic purposes. The bridge was retrofitted 26 years into its life by adding two strips of carbon fiber reinforced polymer (CFRP) due to excessive cracks observed in the beams. Non-destructive field measurements were compared against a detailed finite element analysis of the structure to predict the performance of the girder in terms of deflection and moment capacity before and after the retrofitting work. The analysis was also used to predict the long-term deflections of the structure due to creep, crack distribution, and the ultimate moment capacity of the individual girder. Moreover, the finite element analysis was used to predict the deflection behavior of the overall bridge due to vehicle loading. Good agreement was obtained between the field measurement and the analytical study. A new service life of the structure considering the corrosion and new vehicle demand is carried out based on field measurement using non-destructive testing. Not only are the specific results beneficial for the Indonesian port authority as the stakeholder to manage this structure, but the approach detailed also paves the way for more efficient evaluation of bridges more generally over their service life.

Fatigue Strength and Metal Condition in the Context of Gas Turbine Buckets Life Extension

2012 ◽  
Author(s):  
Sergey A. Ivanov ◽  
Alexander I. Rybnikov
Keyword(s):  
Fatigue Strength ◽  
Service Life ◽  
Gas Turbine ◽  
Fatigue Resistance ◽  
Gas Turbines ◽  
Life Extension ◽  
Term Operation ◽  
Life Estimation ◽  
Metal Properties

Criteria for remaining life estimation and methods for enhancing fatigue resistance of heavy-duty gas turbine bucket metal are based on the analysis of changes in the structure and properties of metal after long-term operation. High-cycle fatigue (HCF) resistance is shown to be a decisive characteristic in the residual life estimation of turbine buckets after operation over 100,000 hours. The tests of the buckets from cast and wrought nickel-based alloys after long-term operation demonstrated decreasing of fatigue strength by up to 25%. The metal structure in operation undergoes notable deterioration mainly in phase redistribution. The size and configuration of metal phases are changing also. It caused the changes in metal properties. The decrease of the bucket fatigue strength correlates with the decrease of metal ductility. The reconditioning heat treatment resulted in restoring mechanical properties of metal. The fatigue resistance also increased nearly to the initial level. The influence of operational factors on bucket fatigue strength deterioration has been established. The mechanical damages on bucket airfoil may decrease the fatigue resistance. We found the correlation of endurance limit and damages depth. The procedures for metal properties recovering and buckets service life substantial extension have been developed. It has resulted in the extension of the buckets service life by up to 50% over the assigned life in gas turbines operated by Gazprom.

Dynamic Life Prediction of RC Structures on Multi-Environmental Time Similarity Method

2011 ◽  
Vol 255-260 ◽  
pp. 220-224 ◽  
Author(s):  
Wei Liang Jin ◽  
Zhi Yuan Li ◽  
Ju Chen ◽  
Jin Quan Wang ◽  
Xiao Zhou Wang
Keyword(s):  
Service Life ◽  
Natural Environment ◽  
Life Prediction ◽  
Indoor Environment ◽  
Prior Information ◽  
Service Life Prediction ◽  
Accelerated Tests ◽  
Rc Structures ◽  
Similarity Method

Multi-environmental time similarity (METS) stepped forward for solving the key technique of service-life correlation of reinforced concrete (RC) structures exposed in artificially accelerated and real natural environment. Artificially accelerated tests and the similarity relationship between natural and indoor environment are used to estimate the prior information. Inspections of the real structure and concrete specimens are used to update the information and reduce the uncertainty in the service-life prediction. The progress of service-life prediction becomes dynamic and long-term.

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