Study on the Lifespan Prediction of Silicon Rubber Nanocomposites Under High Humidity and High Temperature Environment

2020 ◽  
Vol 12 (10) ◽  
pp. 1469-1475
Author(s):  
Dongdong Zhang ◽  
Xin Liu ◽  
Chengshun Yang ◽  
Lianghua Ni ◽  
Xiaoning Huang ◽  
...  
Keyword(s):  
High Temperature ◽  
Operating Time ◽  
Prediction Method ◽  
Test Method ◽  
High Humidity ◽  
Insulation Material ◽  
Test Results ◽  
Silicon Rubber ◽  
Rubber Nanocomposites ◽  
Prediction Parameters

In this paper, the silicon rubber nanocomposites samples cut from the composite insulators operating in high humidity and high temperature areas for 0–13 years were taken as the research object. In accordance to previous research experiences, test methods such as static contact angle method, hardness test method were employed to investigate the changing law of lifespan prediction parameters with operating time. Based on test results, some lifespan prediction parameters significantly correlated with operating time were filtered by means of correlation calculation. On this basis, a prediction method which can be used to determine the operating time of the nanocomposites was proposed based on BP neural network. Test results indicate that lifespan prediction parameters including HC, θ, A, T, H, XO were significantly correlated with the operating time of the insulation material from composite insulator, and these parameters can be used to characterize the aging degree accurately. Besides, due to the high accuracy in experimental verification, the lifespan prediction method proposed in this paper can be used to determine the operating time of composite insulators from transmission lines in future research.

scholarly journals Research on Lifespan Prediction of Cross-Linked Polyethylene Material for XLPE Cables

2020 ◽  
Vol 10 (15) ◽  
pp. 5381
Author(s):  
Yi Zhang ◽  
Zaijun Wu ◽  
Cheng Qian ◽  
Xiao Tan ◽  
Jinggang Yang ◽  
...  
Keyword(s):  
Operating Time ◽  
Prediction Method ◽  
Hardness Test ◽  
High Accuracy ◽  
Future Research ◽  
Test Results ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
Gel Content ◽  
Mechanical And Electrical Properties

In this paper, cross-linked polyethylene (XLPE) cables of the same batch from Factory A, which ran from 1 to 8 years in Jiangsu Province, are sampled. Some widely accepted aging characterization methods of XLPE cables such as the gel content test, differential scanning calorimetry (DSC) test, tensile test and hardness test are employed to obtain the physicochemical, mechanical and electrical properties of the samples. Then, some lifespan prediction parameters significantly correlated with operating time are obtained through correlation calculations. Finally, a prediction method is proposed to predict the operating time of XLPE cables from Factory A. The test results indicate that parameters including the gel content Cge, the crystallinity XC, tensile strength σ, ultimate elongation δ, the dielectric permittivity ε, and the dielectric loss Jtan are significantly correlated with operating time, which can be used in evaluating the aging degree of XLPE cables. Moreover, due to the high accuracy of the experimental verification, it turns out that the lifespan prediction method proposed in this paper can be used to determine the operating time of XLPE cables from Factory A in future research.

Environmental Effects on Mechanical Properties of Modified and Unmodified Carbon Nanotube/Epoxy Resin Nanoomposites

2010 ◽  
Vol 123-125 ◽  
pp. 69-72
Author(s):  
Wei Jen Chen ◽  
Kung Wei Ho ◽  
Yi Luen Li ◽  
Ming Yuam Shen ◽  
Chin Lung Chiang ◽  
...  
Keyword(s):  
High Temperature ◽  
Carbon Nanotube ◽  
Epoxy Resin ◽  
Fourier Transforms ◽  
Mechanical And Thermal Properties ◽  
High Humidity ◽  
Test Results ◽  
Mechanical And Physical Properties ◽  
Fourier Transforms Infrared Spectroscopy ◽  
Thermo Stability

The composites of mechanical and thermal properties of modified and unmodified Carbon nanotube /epoxy resin nanocomposites tested under various circumstances is a major investigation in this study. Identification of functional groups of CNT surface using Fourier transforms infrared spectroscopy (FTIR) was done to male sure if the means of modification adopted in this study is successfully. The tensile and flexural strengths of modified CNT-containing nanocomposites with the amount of modified CNT around 0.75 Phr tested under room temperature circumstance increase 10.96 % and 21.44 % respectively. These two strengths of nanocomposites tested under high temperature circumstance increase 14.55 % and 10.80 % respectively. Additionally, both strengths of nanocomposites tested under high temp.-high humidity circumstance increase 11.65 % and 23.53 % respectively. According to the test results using pyris diamond thermomechanical analyzer (TMA) coefficient decreases 39.81 % with increasing the content of modified CNT and meanwhile glass transition temperature increases 4.15 %. Because of above-mentioned effect, a modified CNs-containing nanocomposite possesses great thermo stability. Overall, No matter what circumstance (high temperature or high temp.-high humidity circumstances) nanocomposites expose to, and no matter whether CNT are modified or not, CNT do significantly enhance mechanical and physical properties of composite.

scholarly journals Evaluation of Micro-Mechanism and High- and Low-Temperature Rheological Properties of Disintegrated High Volume Crumb Rubber Asphalt (DHVRA)

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1145
Author(s):  
Wei Li ◽  
Sen Han ◽  
Xiaokang Fu ◽  
Ke Huang
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Rheological Properties ◽  
Particle Diameter ◽  
Gel Permeation Chromatography ◽  
High Volume ◽  
Crumb Rubber ◽  
Test Method ◽  
Polar Component ◽  
Temperature Performance

The aims of this paper are to prepare disintegrated high volume crumb rubber asphalt (DHVRA) with low viscosity, good workability and low-temperature performance by adding disintegrating agent (DA) in the preparation process, and to further analyze the disintegrating mechanism and evaluated high-temperature and low-temperature rheological properties. To obtain DHVRA with excellent comprehensive performance, the optimum DA dosage was determined. Based on long-term disintegrating tests and the Fluorescence Microscopy (FM) method, the correlations between key indexes and crumb rubber (CR) particle diameter was analyzed, and the evaluation indicator and disintegrating stage division standard were put forward. Furthermore, Fourier transform infrared spectroscopy (FT-IR) and Gel Permeation Chromatography (GPC) was used to reveal the reaction mechanism, and the contact angle test method was adopted to evaluate the surface free energy (SFE). In addition, the high-temperature and low-temperature rheological properties were measured, and the optimum CR content was proposed. Results indicated that the optimum DA dosage was 7.5‰, and the addition of DA promoted the melt decomposition of CR, reduced the viscosity and improved the storage stability. The 135 °C rotational viscosity (RV) of DHVRA from mixing for 3 h could be reduced to 1.475 Pa·s, and the softening point difference was even less than 2 °C. The linear correlation between 135 °C RV and the diameter of CR particle in rubber asphalt system was as high as 0.968, and the viscosity decay rate (VDR) was used as the standard to divide the disintegrating process into a fast disintegrating stage, stable disintegrating stage and slight disintegrating stage. Compared to common rubber asphalt (CRA), DHVRA has an absorption peak at 960 cm−1 caused by trans olefin = C-H, and higher molecular weight and polar component of surface energy. Compared with CRA, although the high-temperature performance of DHVRA decreases slightly, the low-temperature relaxation ability can be greatly improved.

Test results of full-scale high temperature superconductors cable models destined for a 36 kV, 2 kArms utility demonstration

2001 ◽  
Vol 357-360 ◽  
pp. 1241-1244 ◽  
Author(s):  
M. Däumling ◽  
C.N. Rasmussen ◽  
F. Hansen ◽  
D.W.A. Willén ◽  
O.E. Schuppach ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Superconductors ◽  
Full Scale ◽  
Test Results

Characteristics of Phenomena in Powders Type RE2Zr2O7-Al2O3 in High Temperature Annealing Conditions

2011 ◽  
Vol 312-315 ◽  
pp. 583-588 ◽  
Author(s):  
Grzegorz Moskal ◽  
Lucjan Swadźba ◽  
Marek Hetmańczyk ◽  
Bartosz Witala
Keyword(s):  
High Temperature ◽  
Perovskite Oxide ◽  
Differential Scanning Calorimetric ◽  
Test Results ◽  
Dsc Analysis ◽  
Annealing Conditions ◽  
Before And After ◽  
Influence Of Temperature On ◽  
Dta Analysis ◽  
Type Bond

The paper presents test results and characterizes the structural stability of powders, which form a mixture of aluminium oxide (Al2O3) and gadolinium, based on rare earth zirconates. This mixture is provided to create thermal barrier coatings (TBCs) by spraying. The purpose of the tests was to determine the influence of temperature on reactions, occurring between those powders within a temperature range from 25°C to 1500°C, while such conditions were to simulate the conditions, which occur during creation of TBCs and they give an answer to the question concerning mutual reactivity of the powders. The requirements for new materials, provided to spray the TBCs, indicate the necessity to prepare the materials, which do not show tendency towards reactions with the Al2O3, formed during oxidation of Ni (Co) CrAlY, while this reaction is of type bond coat. The tests included differential scanning calorimetric (DSC) analysis and differential thermal analysis (DTA) of powder mixtures. Diffraction analysis was also performed before and after the tests have been finished. The DSC analysis results, obtained at a range of high temperature, did not show any thermal effects, which indicate a low level of mutual reactivity of the powders. However, the DTA analysis suggests presence of such effects at temperature close to 1300°C, and it indicates the necessity to verify exactly the obtained results. Results of the XRD measurement showed that after annealing process already at 1100°C the perovskite oxide of GdAlO3 was present.

Application of Small Punch Test to Evaluate Tensile Properties of SA213T22 Grade Boiler Steel

2015 ◽  
Vol 830-831 ◽  
pp. 191-194
Author(s):  
M. Venkateswara Rao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Tensile Properties ◽  
Test Methods ◽  
Uniaxial Tensile ◽  
Test Results ◽  
Small Punch Test ◽  
Small Punch ◽  
Punch Test ◽  
Aging Phenomena

Conventional tensile test methods are used for service exposed high temperature boiler tubes to evaluate the deterioration in mechanical properties such as tensile strength, yield strength and percentage elongation. The mechanical properties are required to be evaluated periodically as the boiler components undergo material degradation due to aging phenomena. The aging phenomena occurs due to continuous exposure of tubes to high temperature & pressure steam prevailing inside the tubes and high temperature exposure to corrosive combustible gases from the external surfaces within the boiler.A recent developed new technique called small punch testing has been used to evaluate the tensile properties of SA 213T22 grade steel predominantly exists in super-heater and re-heater sections of boiler. The small punch tests have been carried out on the miniature disk shaped specimens of diameter of 8.0 mm and 0.5 mm thickness extracted from both the new and service exposed tubes. Conventional uniaxial tensile tests on standard specimens from the same tube material have also been performed for comparison. The service exposed tubes showed considerable loss in mechanical properties in both the conventional and small punch test results. Correlations of tensile properties have been obtained based on the comparative analysis of both small punch and uniaxial tensile test results. Further, the study showed that an appropriate empirical relation could be generated for new and service exposed materials between both the techniques. Conventional test methods require large quantity of material removal for test samples from in-service components whereas small punch test method needs only a miniature sample extraction. This small punch test technique could also be extended to evaluate the thicker section boiler components such as pipelines and headers in the boiler as a part of remaining life assessment study. Also this technique could be a useful tool to any metallic component where large quantity of sample removal may be difficult or may not be feasible.

The Research of IC Test Based on LTX-77 Test System

2014 ◽  
Vol 496-500 ◽  
pp. 1176-1179
Author(s):  
Li Tan ◽  
Yu Fang
Keyword(s):  
Test Object ◽  
Test System ◽  
Test Method ◽  
Test Results ◽  
Analog Ic ◽  
Test Platform ◽  
Logic Functions ◽  
Actual Test ◽  
Ic Test

LTX-77 test system is a large IC test system that is used for various kinds of analog IC, digital IC and analog digital mixed IC. It can be used to test DC parameters, AC parameters and logic functions. In the paper, the IC test platform is LTX-77 test system. IC ADC0804 was tested as the test object. The test method of IC is described in the view of actual test. The test results show that the test system is convenient and accurate, which has important practical value for IC manufacturers and users.

scholarly journals Temperature Dependence of Mechanical, Electrical Properties and Crystal Structure of Polyethylene Blends for Cable Insulation

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1922 ◽  
Author(s):  
Lunzhi Li ◽  
Lisheng Zhong ◽  
Kai Zhang ◽  
Jinghui Gao ◽  
Man Xu
Keyword(s):  
High Temperature ◽  
Electrical Properties ◽  
Temperature Dependence ◽  
Elevated Temperatures ◽  
Breakdown Strength ◽  
Temperature Stability ◽  
Xrd Analysis ◽  
Insulation Material ◽  
Cable Insulation ◽  
Polyethylene Blends

There is a long-standing puzzle concerning whether polyethylene blends are a suitable substitution for cable-insulation-used crosslinking polyethylene (XLPE) especially at elevated temperatures. In this paper, we investigate temperature dependence of mechanical, electrical properties of blends with 70 wt % linear low density polyethylene (LLDPE) and 30 wt % high density polyethylene (HDPE) (abbreviated as 70 L-30 H). Our results show that the dielectric loss of 70 L-30 H is about an order of magnitude lower than XLPE, and the AC breakdown strength is 22% higher than XLPE at 90 °C. Moreover, the dynamic mechanical thermal analysis (DMA) measurement and hot set tests suggest that the blends shows optimal mechanical properties especially at high temperature with considerable temperature stability. Further scanning electron microscope (SEM) observation and X-ray diffraction (XRD) analysis uncover the reason for the excellent high temperature performance and temperature stability, which can be ascribed to the uniform fine-spherulite structure in 70 L-30 H blends with high crystallinity sustaining at high temperature. Therefore, our findings may enable the potential application of the blends as cable insulation material with higher thermal-endurance ability.

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