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Статті в журналах з теми "Thermal ageing test"
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Sá da Costa, M., Fabienne Farcas, L. F. Santos, M. I. Eusébio, and António Correia Diogo. "Chemical and Thermal Characterization of Road Bitumen Ageing." Materials Science Forum 636-637 (January 2010): 273–79. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.273.
Повний текст джерелаАнотація:
Bitumen ageing stands for a number of physico-chemical modifications that occur in bitumen as a response to environmental conditions. Several tests have been proposed to simulate bitumen ageing. Two of the most common ones are: a) the Rolling Thin Film Oven Test (RTFOT), which simulates short term ageing; b) the Pressure Ageing Vessel (PAV) test, which accounts for long-term ageing and it is usually performed on the RTFOT residue. A study of the physico-chemical modifications of a 50/70 pavement grade bitumen caused by ageing is presented. Both RTFOT and PAV tests were used. A follow-up of bitumen modifications due to ageing was done by several methods. In particular: 1) Fourier transform infrared spectroscopy (FTIR), to follow bitumen oxidation by the increase of oxygenated functional groups, which were quantified by taking appropriate structural indices; 2) Iatroscan thin layer chromatography (TLC), to follow bitumen composition expressed by the generic SARA fractions (saturates, aromatics, resins and asphaltenes); 3) Gel permeation chromatography (GPC), under “ultra-fast” conditions, to follow the colloidal structure of bitumen; and 4) Differential scanning calorimetry (DSC), to evaluate the changes of the crystallized fractions (%FC) and the glass relaxation temperature (Tg). The results show that the PAV test causes more severe changes in bitumen than the RTFOT test. In particular, the evolution of the oxidation processes could be quantified by taking carbonyl and sulfoxide structural indices. Ageing also modified the SARA profile, namely, the relative contribution of aromatics, resins and asphaltenes fractions. On the other hand, DSC data remained almost unaffected after ageing tests, which may be indicative of the survival of most of the phases of the bitumen after these tests. Finally, a comparative analysis of the sensitivity and performance of all these methods is presented.
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Moustafa, Ghareeb. "Ageing of Aluminum Power Connectors Based on Current Cycle Test." European Journal of Engineering Research and Science 4, no. 1 (January 28, 2019): 110–14. http://dx.doi.org/10.24018/ejers.2019.4.1.1103.
Повний текст джерелаАнотація:
The effect of current cycle on the behavior of contact resistance of clamped connectors was investigated experimentally to characterize the thermal behavior of the used clamped connector and optimizing the installation procedure in order to reduce contact resistance and ensure a lower temperature during normal operating conditions. The thermal network method is used for calculating the temperature rise of the connector when loaded by a current. The method is based on substitution of the connector geometry by a circuit consisting of thermal resistances, capacitance and heat sources. The temperature rise is determined using the network simulation program PSPICE with the corresponding thermal model libraries. The validity of the obtained results has been checked by comparing the computed values with those measured experimentally. The agreement was found satisfactory
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Moustafa, Ghareeb. "Ageing of Aluminum Power Connectors Based on Current Cycle Test." European Journal of Engineering and Technology Research 4, no. 1 (January 28, 2019): 110–14. http://dx.doi.org/10.24018/ejeng.2019.4.1.1103.
Повний текст джерелаАнотація:
The effect of current cycle on the behavior of contact resistance of clamped connectors was investigated experimentally to characterize the thermal behavior of the used clamped connector and optimizing the installation procedure in order to reduce contact resistance and ensure a lower temperature during normal operating conditions. The thermal network method is used for calculating the temperature rise of the connector when loaded by a current. The method is based on substitution of the connector geometry by a circuit consisting of thermal resistances, capacitance and heat sources. The temperature rise is determined using the network simulation program PSPICE with the corresponding thermal model libraries. The validity of the obtained results has been checked by comparing the computed values with those measured experimentally. The agreement was found satisfactory
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Choi, Hyun-Jung, Hosang Ahn, Gyeong-Seok Choi, Jae-Sik Kang, and Jung-Ho Huh. "Analysis of Long-Term Change in the Thermal Resistance of Extruded Insulation Materials through Accelerated Tests." Applied Sciences 11, no. 19 (October 8, 2021): 9354. http://dx.doi.org/10.3390/app11199354.
Повний текст джерелаАнотація:
Two experiments were executed to examine the slice accelerated test method, suggested in ISO 11561 “Ageing of thermal insulation materials—Determination of the long-term change in thermal resistance of closed-cell plastics (accelerated laboratory test methods)” and to observe the changes in the thermal performance of insulation material over time by the real-time ageing process. The accelerated test method was conducted for 120 consecutive days using 10 mm thick-sliced specimens, which were sampled from a 50 mm thick plate body. The real-time ageing process was performed for 5000 consecutive days under constant temperature and relative humidity conditions as of 20 ± 5 °C and 50 ± 5% without any slicing. Degradation of thermal performance was shown to be stabilized at around 38 to 41% down from the initial values, which were correspondent with the approximately 10 days after the initial time. The real-time ageing process revealed similar degradation levels at around 130 days after the starting point. Converting the results using the scaling method specified in ISO 11561, the change was found in the range of 37 to 41% for the thermal resistance after 25 years and of 30 to 38% for the 25-year-average thermal resistance, respectively. Within the 10% error range, both the accelerated method and real-time ageing resulted in a similar level of degradation. Consequently, it was our observation that the slice accelerated test was quite enough to predict the practical degradation of insulation materials with at least 90% of accuracy under the specified time duration, temperature and thickness satisfactions.
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Roro, Kittessa T., Bonex Mwakikunga, Ngcali Tile, Brian Yalisi, and Andrew Forbes. "Effect of Accelerated Thermal Ageing on the Selective Solar Thermal Harvesting Properties of Multiwall Carbon Nanotube/Nickel Oxide Nanocomposite Coatings." International Journal of Photoenergy 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/678394.
Повний текст джерелаАнотація:
Varying amounts of dispersed multiwalled carbon nanotubes in NiO have been used to develop composites that absorb the solar energy very well but lose very little through emission. Determination of absorptance,αsol, and emissivity,εther, from such selective solar absorbers shows that the optimum efficiency of 71% can be attained when about 10 mg of MWCNTs are composited with NiO. One such absorber was subjected to thermal ageing tests. The performance criterion (PC) limit for passing the test when simulated for 25 years is(−Δα+0.25Δε)≤0.05. It was found that the typical absorber had a PC value of −0.01. This value is much better than the passing limit. Raman spectra of the typical absorber before and after the thermal ageing test showed a reduced intensity in the D and G bands of disordered and graphitic carbon, respectively but an enhancement of the NiO bands indicating loss of carbon atoms due to thermal ageing tests. Simple equations are derived determining the proportion of carbon atoms that are lost and the proportion of carbon atoms that remains in the absorber; both of these are in agreement with the original carbon composition before the thermal ageing test. It is reported that the typical absorber will retain 63% of the carbon after 25 years.
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Zhang, Hui, Tao Yu, Jian Feng Sheng, and Qiong Yu. "Thermal Class Evaluation of Glass Net Used for Transformer." Advanced Materials Research 893 (February 2014): 75–79. http://dx.doi.org/10.4028/www.scientific.net/amr.893.75.
Повний текст джерела
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Zaghdoudi, Kömmling, Jaunich, and Wolff. "Scission, Cross-Linking, and Physical Relaxation during Thermal Degradation of Elastomers." Polymers 11, no. 8 (July 31, 2019): 1280. http://dx.doi.org/10.3390/polym11081280.
Повний текст джерелаАнотація:
Elastomers are susceptible to chemical ageing, i.e., scission and cross-linking, at high temperatures. This thermally driven ageing process affects their mechanical properties and leads to limited operating time. Continuous and intermittent stress relaxation measurements were conducted on ethylene propylene diene rubber (EPDM) and hydrogenated nitrile butadiene rubber (HNBR) samples for different ageing times and an ageing temperature of 125 °C. The contributions of chain scission and cross-linking were analysed for both materials at different ageing states, elucidating the respective ageing mechanisms. Furthermore, compression set experiments were performed under various test conditions. Adopting the two-network model, compression set values were calculated and compared to the measured data. The additional effect of physical processes to scission and cross-linking during a long-term thermal exposure is quantified through the compression set analysis. The characteristic times relative to the degradation processes are also determined.
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Boxhammer, Jörg. "Shorter test times for thermal- and radiation-induced ageing of polymer materials." Polymer Testing 20, no. 7 (2001): 719–24. http://dx.doi.org/10.1016/s0142-9418(01)00029-0.
Повний текст джерела
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Wang, Yongqiang, Changhui Feng, Ruoyu Fei, and Yu Luo. "Thermal-ageing characteristics of dry-type transformer epoxy composite insulation." High Performance Polymers 32, no. 7 (February 26, 2020): 741–52. http://dx.doi.org/10.1177/0954008320906439.
Повний текст джерелаАнотація:
To study the ageing characteristics of epoxy resin composite insulation in dry-type transformers in high-temperature environments, glass fibre-reinforced epoxy resin samples were placed in a hot air ageing environment at 130°C for testing. Dielectric properties, partial discharge (PD), microscopic morphology, three-dimensional morphology and Fourier transform infrared spectroscopy of aged samples were periodically tested. The results show that during the ageing process, the change in the surface morphology of the sample leads to an overall upward trend in surface roughness, and the older the sample, the faster the surface roughness increases; changes in the surface morphology and three-dimensional morphology of the material constitute the basis for judging the condition of the insulating surface and the state of ageing development. Microcracks are the direct cause of debonding of glass fibres and epoxy matrix. Degradation of the sample during the ageing process generates many free radicals, which enhances the polarisation ability of the sample and increases both the dielectric constant and the dielectric loss factor. The real part of the complex dielectric constant is more sensitive to the ageing response of the sample. The older the sample, the greater the effect on the results of the dielectric spectrum test. Since the aged sample generates more hot electrons during the PD process and makes it easier to inject electrons into the material, the PD of the sample is rendered more intense by thermal ageing. There is a significant difference between the degradation mechanism of the thermal ageing and PD. The samples subjected to PD after thermal ageing produce new groups, and the degradation of the samples is more severe than that caused by thermal ageing, or PD, alone.
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Pellecuer, Guillaume, Jean-Jacques Huselstein, Thierry Martiré, François Forest, André Chrysochoos, and Mourad Jebli. "IGBT Wirebonds Ageing: A New Test Bench Development for Dedicated Modules Assemblies." European Journal of Electrical Engineering 24, no. 4 (August 31, 2022): 161–69. http://dx.doi.org/10.18280/ejee.240401.
Повний текст джерелаАнотація:
Wirebonds ageing in power modules used in electric vehicles is a main concern for the development of reliable inverters. The development of a specific test bench to study the evolution of their properties over time has allowed conclusions to be drawn on the possibility of accelerating or not accelerating ageing tests without distorting the mechanisms actually involved in ageing. Through the use of specifically developed test bench in terms of electrical and thermal properties the studied wirebonds samples are more easily thermally controllable, equipped with measuring devices and the energy consumption at a given cycle is divided by ten compared to a classical bench. The entire process of designing and producing the specific samples and the associated test bench and a description of the first results obtained to demonstrate the relevance of the approach is given.
Дисертації з теми "Thermal ageing test"
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Sabbah, Wissam. "Contribution à l’étude des assemblages et connexions nécessaires à la réalisation d’un module de puissance haute température à base de jfet en carbure de silicium (SiC)." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR12013/document.
Повний текст джерелаАнотація:
Le développement de composants de puissance à base de carbure de silicium (SiC) permet la réalisation d’interrupteurs pouvant fonctionner au-delà de 200°C. Le silicium présente plus de limitations au niveau physique du matériau qu’au niveau des technologies d’assemblages. Le SiC est un matériau semi-conducteur grand gap ce qui permet d’obtenir des courants de fuite inverse qui restent faibles à haute température ; d’où un fort intérêt pour des applications haute température. Mise à part son utilisation à des températures pouvant dépasser les 300°C, c’est un matériau qui permet aussi d’augmenter les fréquences de commutation ainsi que la densité de puissance par rapport à des composants à technologie silicium. Ceci en fait un candidat idéal pour des applications forte puissance dans le domaine de la traction, des protections de réseaux électriques ou de la transmission et de la distribution d’énergie. L’utilisation du SiC pour une application haute température pose le problème de son packaging, des choix de matériaux et de sa configuration. Cette thèse a pour but d’effectuer une étude de fiabilité et de durée de vie des briques technologiques d’assemblage et de connexions nécessaires à la réalisation d’un cœur de puissance haute température à base de JFET SiC. Une étude des différentes technologies d’assemblages de convertisseurs de puissance haute température est effectuée afin de définir différentes briques technologiques constitutives de ces systèmes. Cette première étude nous permet de procéder à une sélection de certaines technologies d’assemblages comme le frittage de pâtes d’argent pour la technologie de report de puces. Ces briques technologiques feront l’objet d’études plus approfondies allant de la réalisation de véhicules tests jusqu’à la mise au point des essais de cyclages associés aux techniques d’analyse nécessaires à l’étude de leur défaillance.Les études expérimentales concernent des essais de cyclage passif et de stockage thermique, l’apparition de délaminages en cours de cyclage thermique (scan acoustique, RX), le report par frittage de pâtes d’argent nano et microscopiques et la caractérisation électrique et thermique (Rth, I[V])The development of power components based on silicon carbide (SiC) allows for the design of power converter operating at high temperature (above 200 or 300°C). SiC is a semiconductor material with a large band gap that not only can operate in temperatures exceeding 300°C but also offers fast switching speed, high voltage blocking capability and higher thermal conductivity compared to silicon technology components. The classical die attach technology uses high temperature solder alloys which melt at around 300°C. However, even a soldered die attach with such high melting point can only operate up to a much lower temperature. Alternative die attach solutions have recently been proposed: Transient Liquid Phase Bonding, soldering with higher melting point alloys such as ZnSn, or silver sintering.Silver sintering is a very interesting technology, as silver offers very good thermal conductivity (429W/m.K, better than copper), relatively inexpensive (compared to alternative solutions which often use gold), and has a very high melting point (961°C).The implementation of two silver-sintering processes is made: one based on micrometer-scale silver particles, and one on nano-meter-scale particles. Two substrate technologies are investigated: Al2O3 DBC and Si3N4 AMB. After the process optimization, tests vehicles are assembled using nano and micro silver particles paste and a more classical high-temperature die attach technology: AuGe soldering. Multiple analyses are performed, such as thermal resistance measurement, shear tests and micro-sections to follow the evolution of the joint during thermal cycling and high-temperature storage ageing
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Ahose, Komla Dela Mawulawoe. "Caractérisation et modélisation du vieillissement thermique d'élastomères chargés par une approche multiphysique." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0726/document.
Повний текст джерелаАнотація:
Cette étude s'intéresse au vieillissement thermique d'élastomères synthétiques, amorphes, vulcanisés et additionnés de charges (noir de carbone). Sur la base d'une même formulation matériau, on étudie plus particulièrement, l'impact du procédé initial (conditions de vulcanisation), les conséquences de l'évolution physico-chimique des matériaux sur le comportement mécanique et l'influence d'un chargement mécanique permanent durant le vieillissement. Des caractérisations mécaniques (essais cycliques, relaxations par paliers, essais de compressibilité) et physico-chimiques (suivi des variation de dimension et de masse, essais de gonflement dans un solvant) sont réalisées afin de quantifier l'impact du vieillissement. Le phénomène dominant étant une augmentation de la densité de réticulation (maturation des ponts polysulfures en ponts disulfures ou monosulfures). D'une manière générale la partie expérimentale a permis de formuler un certain nombre d'hypothèses (isotropie, insensibilité de certaines caractéristiques physiques aux vieillissement, etc.) qui ont guidé le développement d'un modèle multiphysique. Ce modèle s'appuie sur une approche thermo-chimio-mécanique formulée dans le cadre de la thermodynamique des processus irréversibles avec introduction de variables internes afin de traduire d'une part les non-linéarités de comportement de ce type de matériau (grandes déformations, viscoélasticité non-linéaire et effet Payne), et d'autre part de décrire l'évolution physico-chimique du réseau macromoléculaire (qui dépend de la température et de l'état mécanique). Cette modélisation a permis d'introduire un couplage réciproque entre les états physico-chimique et mécaniqueThis study mainly concerns the thermal aging phenomenon in amorphous synthetic rubbers, initially vulcanized and filled with carbon blacks. On the basis of one material formulation, we study: the impact of the process (vulcanization condition), the influence of the chemo-physical evolution of the cross-linked network on the mechanical behavior and the influence of a permanent mechanical load during aging. Mechanical characterizations (cyclic, relaxation and hydrostatic tests) and chemo-physical ones (variation of mass and volume, swelling in solvent) are realized in order to quantify the impact of ageing. The main phenomena observed is an increase of the crosslink density (maturation of polysulfides to monosulfide or disulfide crosslinks). From a general point of view, we can formulate many hypothesis from the experimental characterizations (isotropy, non-dependence of some physical properties on ageing, etc.). For the modeling, we have adopted a themo-chemo-mechanical approach that is based on the thermodynamics of irreversible processes and the introduction of internal variables in order to phenomelogically describe on one hand the nonlinear mechanical behavior at finite strain (nonlinear viscoelasticty, Payne effect, etc.) and on the other hand the chemo-physical evolution of the macromolecular network (which depends on temperature and mechanical state). This approach has permitted to introduce a reciprocal coupling between chemo-physical and mechanical states
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Dbeiss, Mouhannad. "Mission Profile-Based Accelerated Ageing Tests of SiC MOSFET and Si IGBT Power Modules in DC/AC Photovoltaic Inverters." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT020/document.
Повний текст джерелаАнотація:
Dans le cas des installations photovoltaïques, l’onduleur est le premier élément défaillant dont il est difficile d’anticiper la panne, et peu d’études ont été faites sur la fiabilité de ce type de convertisseur. L'objectif de cette thèse est de proposer des outils et méthodes en vue d'étudier le vieillissement des modules de puissance dans ce type d'application en se focalisant sur les phénomènes de dégradation liés à des aspects thermomécaniques. En règle générale, le vieillissement accéléré des modules de puissance est effectué dans des conditions aggravées de courant (Cyclage Actif) ou de température (Cyclage Passif) pour accélérer les processus de vieillissement. Malheureusement, en appliquant ce type de vieillissement accéléré, des mécanismes de défaillances qui ne se produisent pas dans la vraie application peuvent être observés et, inversement, d'autres mécanismes qui se produisent habituellement peuvent ne pas apparaître. La première partie de la thèse se focalise donc sur la mise en place d'une méthode de vieillissement accéléré des composants semi-conducteurs des onduleurs photovoltaïques. Cela est fait en s’appuyant sur l’analyse des profils de mission du courant efficace de sortie des onduleurs et de la température ambiante, extraits des centrales photovoltaïques situées au sud de la France sur plusieurs années. Ces profils sont utilisés pour étudier les dynamiques du courant photovoltaïque, et sont introduites dans des modèles numériques pour estimer les pertes et les variations de la température de jonction des semi-conducteurs utilisés dans les onduleurs, en utilisant l’algorithme de comptage de cycles "Rainflow". Cette méthode est ensuite mise en œuvre dans deux bancs expérimentaux. Dans le premier, les composants sous test sont des modules IGBT. Les composants sont mis en œuvre dans un banc de cyclage utilisant la méthode d'opposition et mettant en œuvre le profil de vieillissement défini précédemment. Un dispositif in-situ de suivi d'indicateurs de vieillissement (impédance thermique et résistance dynamique) est également proposé et évalué. Le deuxième banc est consacré à l'étude de modules de puissance à base de MOSFET SiC. Le vieillissement est effectué dans les mêmes conditions que pour les modules IGBT et de nombreux indicateurs électriques sont monitorés mais, cette fois ci, en extrayant les composants de l'onduleur de cyclage. Les résultats obtenus ont permis de déterminer des indicateurs de vieillissement d’IGBT et de MOSFET SiC utilisés dans un onduleur photovoltaïqueIn the case of photovoltaic installations, the DC/AC inverter has the highest failure rate, and the anticipation of its breakdowns is still difficult, while few studies have been done on the reliability of this type of inverter. The aim of this PhD is to propose tools and methods to study the ageing of power modules in this type of application, by focusing on ageing phenomena related to thermo-mechanical aspects. As a general rule, the accelerated ageing of power modules is carried out under aggravated conditions of current (Active Cycling) or temperature (Passive Cycling) in order to accelerate the ageing process. Unfortunately, when applying this type of accelerated ageing tests, some failure mechanisms that do not occur in the real application could be observed, while inversely, other mechanisms that usually occur could not be recreated. The first part of the PhD focuses on the implementation of an accelerated ageing method of the semiconductor devices inside photovoltaic inverters. This is accomplished by analyzing the mission profiles of the inverter’s output current and ambient temperature, extracted over several years from photovoltaic power plants located in the south of France. These profiles are used to study photovoltaic current dynamics, and are introduced into numerical models to estimate losses and junction temperature variations of semiconductors used in inverters, using the cycle counting algorithm “Rainflow”. This method is then performed in two experimental test benches. In the first one, the devices under test are IGBT modules, where the accelerated ageing profile designed is implemented using the opposition method. Moreover, an in-situ setup for monitoring ageing indicators (thermal impedance and dynamic resistance) is also proposed and evaluated. The second bench is devoted to study the ageing of SiC MOSFET power modules. The accelerated ageing test is carried out under the same conditions as for the IGBT modules with more monitored electrical indicators, but this time by disconnecting the semiconductor devices from the inverter. The results obtained allowed to determine several potential ageing indicators of IGBTs and SiC MOSFETs used in a photovoltaic inverter
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Zhang, Yuanci. "Performance and ageing quantification of electrochemical energy storage elements for aeronautical usage." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0029/document.
Повний текст джерелаАнотація:
Dans un contexte de progression du stockage d’énergie sous forme électrochimique dans les transports, notamment dans l’aéronautique, les problématiques de performance, de fiabilité, de sureté de fonctionnement et de durée de vie du stockeur sont essentielles pour utilisateurs. Cette thèse se focalise ces voltes pour l’avion plus électrique. Les technologies étudiées correspondent à des éléments commerciaux de dernière génération de type Lithium-ion (NMC/graphite+SiO, NCA/graphite, LFP/graphite, NMC/LTO), Lithium-Soufre (Li-S), supercondensateur et hybride (LiC). Une première partie de ce manuscrit s’attache à la quantification des performances des différents éléments dans l’environnement aéronautique [-20°C, 55°C] et pour l’usage aéronautique. Un modèle comportemental de type électro-thermique est développé et validé. La seconde partie est consacrée à la quantification du vieillissement des différents éléments. Les résultats de vieillissement calendaire et en cyclage actif sont présentés ainsi que ceux des tests abusifs. Une méthode d’estimation de l’état de santé (SOH) des éléments basés sur l’analyse de la capacité incrémentale (ICA) est proposée. Enfin, l’évaluation de la robustesse des éléments de stockage lors de tests de vieillissement accéléré avec un profil spécifique à l’usage aéronautique est proposé. Les modèles de vieillissement et la méthode d'estimation de SOH proposés précédemment sont utilisés ici pour évaluer l'impact de la température sur la vitesse de dégradation et pour estimer le SOH des cellules vieillies à l’aide de ce profil aéronautiqueIn the context of progress in the electrochemical energy storage systems in the transport field, especially in the aeronautics, the issues of performance, reliability, safety and robustness of these elements are essential for users. This thesis is focused on these issues for the more electric aircraft. The technologies studied correspond to the latest generation commercial elements of Lithium-ion batteries (NMC/ graphite + SiO, NCA/graphite, LFP/graphite, NMC/LTO), Lithium-Sulfur (Li-S), Supercapacitor and Lithium-ion capacitors. The first part of this manuscript is dedicated to the performance quantification of the different electrochemical energy storage elements in aeronautical environment [-20°C, 55°C] and usage. An efficient and accurate electro-thermal model is developed and validated. The second part is devoted to the calendar and power cycling ageings as well as to the presentation of abuse testing results. A State Of Health (SOH) estimation based on incremental capacity analysis method is proposed. Finally, the robustness of the storage elements during accelerated ageing tests with a specific profile for the aeronautical usage is evaluated. The ageing models and SOH estimation methods proposed in the previous sections are used here to evaluate the impact of temperature on the degradation rate and to estimate the SOH of the cells with this aeronautical profile
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Agustin, Fernando. "The Investigation of Tree-Retardant Ethylene Propylene Rubber Insulated Medium Voltage Cable as an Alternative Underground Cable for Victorian Power Distribution Network." Thesis, 2021. https://vuir.vu.edu.au/42431/.
Повний текст джерелаАнотація:
Cross-linked Polyethylene (XLPE) underground cables are widely used in Victorian power distribution networks due to its lower Dielectric Dissipation Factor (DDF) over Ethylene Propylene Rubber (EPR) cable. Advancement in compounding technology led to the reduction of DDF in some EPR proprietary material.
This research investigated the viability of silane-cured low-DDF Tree-Retardant EPR (TR-EPR) cable as an alternative over standard XLPE cable in Victoria. The thermal ageing behaviour of TR-EPR was studied by means of laboratory-based experimentation using accelerated ageing test to observe the time variation of its mechanical properties: tensile strength and elongation at break. Measurements of Partial Discharge (PD) were also conducted prior and after cable heating at service temperature. The results of the thermal ageing test and PD measurements were visually presented through graphs and plots. For the thermal ageing, a theoretical life model was used with the parameters determined using Least Square Regression Method (LSRM). Data from the TR- EPR thermal ageing test were mathematically extrapolated to service temperature through the Arrhenius law to determine the extent of validity of the results. The economic viability of the TR- EPR was also analysed. The results obtained can be utilised by network operators and large industrial companies when designing their underground cable system and taking into consideration the reliability and economy of the power system.
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"Evaluation of performance of in-use firefighters’ protective clothing using non-destructive tests." Thesis, 2013. http://hdl.handle.net/10388/ETD-2013-12-1359.
Повний текст джерелаАнотація:
Firefighters’ coats and pants, referred to as firefighters’ protective clothing in this research, are made of similar fabrics and often include three layers: an outer shell, a moisture barrier, and a thermal liner. Minimum requirements of firefighters’ protective clothing performance have been clearly established by various national and international standards for new clothing to ensure the reasonable safety of firefighters. However, there are no clear guidelines on the requirements for continuing performance of firefighters’ protective clothing. In general, the protection offered by firefighters’ protective clothing is expected to deteriorate over time, but it is still uncertain how destructive different exposures are and how long a piece of firefighters’ protective clothing can continue to protect a firefighter to an acceptable level.
Non-destructive techniques are preferable in order to investigate how the performance of protective clothing may change with time since this allows firefighters’ protective clothing to return to service after a test. These non-destructive methods, which could be used to monitor the level of deterioration in firefighters’ protective clothing performance and to make decisions on retirement of individual pieces of protective clothing, would be extremely useful for fire departments in Canada and other countries.
Thermal exposure is an important factor in ageing of firefighters’ protective clothing during firefighting operations. Outer shell and moisture barrier specimens made of common fabrics used in construction of firefighters’ protective clothing, and of different colours, were exposed to different levels of thermal exposure simulated using a cone calorimeter in single and multiple stages. Tensile strength of outer shell specimens, and tear strength, water vapour transmission rate, and water penetration pressure of moisture barrier specimens, which are critical aspects of performance of firefighters’ protective clothing, were measured. In order to explain the changes in performance after thermal exposure, the temperature profile of specimens during each thermal exposure was recorded. Furthermore, thermogravimetric analysis for each specimen material was carried out and images of the surface of specimens were obtained using scanning electron microscope. The test results demonstrated that tensile strength of outer shell specimens deteriorated faster than other aspects of performance.
Two non-destructive techniques, colour measurement and near infrared spectroscopy, were implemented to correlate tensile strength of outer shell specimens with discoloration and reflectance spectrum. Two types of correlation between tensile strength and colour change were identified among the tested fabrics, depending on the initial fabric colour, which could be a basis to develop numerical models to predict tensile strength of outer shell specimens. Linear predictive equations were developed using a numerical code based on regression analysis, which correlated tensile strength with reflectance of outer shell specimens within the wavelength region of 1500-2500 nm. A three-variable model predicted tensile strength of thermally aged test specimens, the tensile strength of which were 600 N and higher, with a relative error of up to 10%. For test specimens with tensile strength of about 300 N, the relative error was 55%. The difference in error percentage was related to a gap in training data points for the model within the tensile strength range of 300 - 600 N.
Частини книг з теми "Thermal ageing test"
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Emsley, Alan M., Richard J. Heywood, and Gary C. Stevens. "Ultra-Accelerated Thermal Ageing Tests." In Ageing Studies and Lifetime Extension of Materials, 277–82. Boston, MA: Springer US, 2001. http://dx.doi.org/10.1007/978-1-4615-1215-8_30.
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Tserpes, Konstantinos, Elli Moutsompegka, Mareike Schlag, Kai Brune, Christian Tornow, Ana Reguero Simón, and Romain Ecault. "Characterization of Pre-bond Contamination and Aging Effects for CFRP Bonded Joints Using Reference Laboratory Methods, Mechanical Tests, and Numerical Simulation." In Adhesive Bonding of Aircraft Composite Structures, 51–117. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-319-92810-4_2.
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AbstractIn this chapter, the pre-bond contamination and ageing effects on carbon fiber reinforced plastic (CFRP) adherends and CFRP bonded joints are characterized by means of reference laboratory non-destructive testing (NDT) methods, mechanical tests, and numerical simulation. Contaminations from two fields of application are considered, namely in aircraft manufacturing (i.e. production) and for in-service bonded repair. The production-related scenarios comprise release agent, moisture, and fingerprint, while the repair-related scenarios comprise fingerprint, thermal degradation, de-icing fluid, and a faulty curing of the adhesive. For each scenario, three different levels of contamination were pre-set and applied, namely low, medium and high level. Furthermore, two types of samples were tested, namely coupons and pilot samples (a stiffened panel and scarf repairs). The CFRP adherends were contaminated prior to bonding and the obtained surfaces were characterized using X-ray photoelectron spectroscopy. After bonding, the joints were tested by ultrasonic testing. To characterize the effects of each contamination on the strength of the bonded joints, mode-I and mode-II fracture toughness tests, and novel centrifuge tests were conducted on the coupons, while tensile tests were performed on the scarfed samples. Additionally, numerical simulation was performed on CFRP stiffened panels under compression using the LS-DYNA finite element (FE) platform.
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Sun, Xiaowei, Miao Gao, Honghong Zhou, Jing Lv, and Zhaoyang Ding. "Influence of Fiber on Properties of Graphite Tailings Foam Concrete." In Lecture Notes in Civil Engineering, 508–15. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-1260-3_46.
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AbstractThe project used graphite tailings as a filler to prepare graphite tailings foamed concrete. Mainly studied the physical properties, mechanical properties and thermal properties of the foam concrete by graphite tailings, also studied the combination of polypropylene fiber and glass fiber influence of foam concrete compressive strength and cracking strength. The experimental results show that in the case of the same dry density grade, adding 20% graphite tailings can make the foam concrete strength reach its peak. When the water-binder ratio is 0.65 and the self-made chemical foaming agent content is 7%, the optimal total fiber volume blending rate is 0.18%, and the blending ratio of polypropylene fiber and glass fiber is 2:1. The compounding of polypropylene fiber and glass fiber can improve the flexural performance of foam concrete, which is not conducive to the thermal insulation performance of foam concrete, but the test results are still better than industry standards.
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Valdez-Rodríguez, S., B. Campillo, and J. J. Islas. "Microstructure and Microhardness of AlZnMnMg Alloy During Heat Treatment." In Encyclopedia of Aluminum and Its Alloys. Boca Raton: CRC Press, 2019. http://dx.doi.org/10.1201/9781351045636-140000189.
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In this work, the structural changes induced by the chemical nature of alloyed elements and aged treatment showed a beneficial connection with hardness and electrochemical degradation performance. Al-based alloys were investigated by means of the Vickers hardness test, in order to determine the effect of aging treatment on the hardness; X-ray diffraction and scanning electron microscopy were used to identify the phase transformation by the casting and ageing treatment; finally, a short-term electrochemical test to know the electrochemical performance. The results show that the formation of the (MgZn)49Al32 phase occurs under two conditions: when the magnesium content is more than 5.49% in as-cast condition, and the thermal treatment carried out at 450°C for 5 h. In addition, the hardness and electrochemical performance have been influenced by the presence and quantity of the (MgZn)49Al32 phase. The addition of magnesium alloy modifies the microstructure, increases the content of the (MgZn)49Al32 phase, and provides a localized corrosion, which leads to the breakdown of the oxide film (γ-Al2O3) formed on the Al alloy surface.
Тези доповідей конференцій з теми "Thermal ageing test"
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Lusuardi, Luca, Andrea Cavallini, Vincenzo Madonna, Paolo Giangrande, and Michael Galea. "Unconventional accelerated thermal ageing test for traction electric motors in vehicles." In 2020 IEEE Electrical Insulation Conference (EIC). IEEE, 2020. http://dx.doi.org/10.1109/eic47619.2020.9158744.
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Gu, Lingyun, Qiuhuang Han, Feipeng Wang, Kaizheng Wang, Chenmeng Xiang, Changkai Shi, Yan Wu, and Xuefeng Bai. "Dissolved Gas Analysis in Camellia Insulating Oil during Thermal Ageing Test." In 2019 2nd International Conference on Electrical Materials and Power Equipment (ICEMPE). IEEE, 2019. http://dx.doi.org/10.1109/icempe.2019.8727299.
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Ayadi, Mohamed, Olivier Briat, Richard Lallemand, Gerard Coquery, and Jean-Michel Vinassa. "Influence of thermal cycling on supercapacitor performance fading during ageing test at constant voltage." In 2014 IEEE 23rd International Symposium on Industrial Electronics (ISIE). IEEE, 2014. http://dx.doi.org/10.1109/isie.2014.6864892.
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Timms, Chris, Doug Swanek, Duane DeGeer, Arjen Meijer, Ping Liu, Erich Jurdik, and Jay Chaudhuri. "TurkStream Collapse Test Program." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-78454.
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The TurkStream pipeline project is designed to transport approximately 32 billion cubic meters of natural gas annually from Russia to Turkey under the Black Sea, with more than 85% of the deep-water route being deeper than 2000 m. The offshore section is intended to consist of two parallel lines, each approximately 900 km long. The preliminary stages of the front end engineering design (pre-FEED) phase was managed by INTECSEA. To support the analyses and design of the deepest portions, a full scale collapse test program was performed by C-FER Technologies (C-FER). This collapse test program, which included 62 full-scale collapse and pressure+bend tests, 54 medium-scale ring collapse tests, and hundreds of small-scale tests, was primarily aimed at measuring, quantifying and documenting the increase in pipe strength and collapse resistance resulting from the thermal induction heat treatment effect (thermal ageing) that arises during the pipe coating process. Two grades of 32-inch (813 mm) outside diameter (OD) line-pipe, SAWL450 and SAWL485 with wall thicknesses of 39.0 mm or 37.4 mm, respectively, were supplied from various mills for testing. The collapse test program objectives were as follows: • Determine the collapse resistance of line pipes originating from various pipe mills; • Determine the pressure+bend performance of line pipes originating from various pipe mills; • Measure the effect of thermal ageing on material and collapse testing results, including the impact of multiple thermal cycles; and • Evaluate the results of medium-scale ring collapse tests as compared to full-scale tests. This paper presents selected results of this work, along with some comparisons to predictive equations.
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Ramteke, P. K., A. K. Ahirwar, N. B. Shrestha, V. V. S. Sanyasi Rao, K. K. Vaze, and A. K. Ghosh. "Thermal ageing predictions of polymeric insulation cables from Arrhenius plot using short-term test values." In 2010 2nd International Conference on Reliability, Safety and Hazard - Risk-Based Technologies and Physics-of-Failure Methods (ICRESH). IEEE, 2010. http://dx.doi.org/10.1109/icresh.2010.5779569.
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Eiselt, Charles C., Günter König, Hieronymus Hein, Maxim Selektor, and Martin Widera. "Investigation of Thermal Ageing in Long Term Operated RPV Materials." In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45558.
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The phenomenon of thermal ageing of low alloy steels comes more into focus in terms of long term operation of nuclear power plants (NPP). Safety-relevant components such as the RPV or the pressurizer have to bear the respective loads at elevated temperatures for longer times. However the mechanical properties of the applied materials might experience certain degradations such as a decrease of the impact energy levels and a shift in the ductile to brittle transition temperature (e.g. T41) leading to higher ductile-brittle reference temperatures and a reduction of material toughness. In terms of a safe long term operation it is important to understand in how far thermal ageing alone, meaning for the RPV without the cumulative damaging effects through neutron irradiation, has detrimental influences on the respective materials of interest. First of all an overview is provided of the current state of the art with respect to thermal ageing by describing influencing mechanisms, its implementation into different nuclear codes, standards and selected experimental investigations in this field. Following this, the test results of the thermal surveillance sets from three German PWRs are presented and discussed. The tested Charpy-V specimens, taken from representative RPV base and weld metals (22NiMoCr3-7 / NiCrMo1UP) as well as their heat affected zones, were exposed to ∼290°C for ∼30 years on the cold leg of the according plants’ main coolant loops. The obtained results are compared with the existing thermal aging data base (baseline and ∼7 years data) of the materials concerned. Finally, the role of thermal ageing particularly with respect to RPV irradiation surveillance will be assessed.
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Melve, Bjo̸rn, Dana Ali, Jan-Christian Hu¨bert, and Steinar Hommedal. "Qualification of Subsea Thermal Insulation for Extreme Temperatures." In ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/omae2004-51595.
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The Kristin field in the Norwegian Sea have a flowing wellhead temperature of 162 °C. This is believed to be the maximum temperature for an insulated subsea wellhead experienced to date. An extensive qualification program for the corrosion coating and thermal insulation was performed including accelerated ageing in water at elevated temperatures. The most critical test was the insulated hot plate test with holes down to the steel surface. For the extreme temperature of 162 °C a phenolic syntactic foam system showed the “least worse” results, and was chosen as the insulation system.
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Immovilli, Fabio, Claudio Bianchini, Alberto Bellini, and Andrea Sala. "A test bench for accelerated thermal ageing of III–V concentration solar cells using forward bias injection." In 2011 IEEE Energy Conversion Congress and Exposition (ECCE). IEEE, 2011. http://dx.doi.org/10.1109/ecce.2011.6063743.
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Hossain, S., C. E. Truman, D. J. Smith, and P. J. Bouchard. "Measurement of Residual Stresses in a Nozzle-to-Cylinder Weld After Thermal Ageing at 550°C." In ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/pvp2007-26263.
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This paper presents results from a programme of experimental measurements of residual stresses in a type 316H stainless steel component consisting of a nozzle welded to a cylinder. The residual stresses were measured using the deep-hole drilling (DHD) technique. The welded component had been thermally aged in a furnace at 550°C for 19,644 hours prior to the residual stress measurements. Measurements were obtained in the through-thickness section of the component at two locations: (i) in the cylinder heat affected zone (HAZ) at the flank of the nozzle-to-cylinder weld intersection and (ii) in the cylinder HAZ near the crown of the nozzle-to-cylinder weld intersection. The stress measurements made after the furnace heat soak treatment are compared with the earlier as-welded stress measurements. In comparison with as-welded residual stress measurements on the same component and with residual stresses in a service-aged (55,000 hours at 525°C) component, it was evident that the thermal soak test treatment had significantly relaxed the weld residual stresses. In particular the soak test hoop stress profile was almost identical to the service-aged condition, whereas the transverse stress distribution had only been partially relaxed by the thermal soak test.
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Kang, Ki Sig. "Qualification, Condition Monitoring, and Management of Ageing of Low Voltage Cables in Nuclear Power Plant." In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45188.
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The International Atomic Energy Agency (IAEA) organized an international Coordinated Research Project (CRP) on qualification, condition monitoring, and management of low voltage cables for life management in nuclear power plant. A total of 16 organizations from Technical Service Organizations (TSOs), and Research & Development Organization participated in the CRP and tested and presented their experimental results. The CRP members are actively engaged in providing cable samples, thermal and radiation ageing of cables, and electrical, mechanical, and chemical testing of cables samples. Preliminary analysis of the test data received show that, for some of the Condition Monitoring (CM) methods, good correlation is observed with ageing time and there is consistency in measurements between the different test labs carrying out the tests. The level of correlation with ageing time and the degree of variability between labs is dependent on the material being tested and the CM method being used.
Звіти організацій з теми "Thermal ageing test"
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Baral, Aniruddha, Jeffrey Roesler, M. Ley, Shinhyu Kang, Loren Emerson, Zane Lloyd, Braden Boyd, and Marllon Cook. High-volume Fly Ash Concrete for Pavements Findings: Volume 1. Illinois Center for Transportation, September 2021. http://dx.doi.org/10.36501/0197-9191/21-030.
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High-volume fly ash concrete (HVFAC) has improved durability and sustainability properties at a lower cost than conventional concrete, but its early-age properties like strength gain, setting time, and air entrainment can present challenges for application to concrete pavements. This research report helps with the implementation of HVFAC for pavement applications by providing guidelines for HVFAC mix design, testing protocols, and new tools for better quality control of HVFAC properties. Calorimeter tests were performed to evaluate the effects of fly ash sources, cement–fly ash interactions, chemical admixtures, and limestone replacement on the setting times and hydration reaction of HVFAC. To better target the initial air-entraining agent dosage for HVFAC, a calibration curve between air-entraining dosage for achieving 6% air content and fly ash foam index test has been developed. Further, a digital foam index test was developed to make this test more consistent across different labs and operators. For a more rapid prediction of hardened HVFAC properties, such as compressive strength, resistivity, and diffusion coefficient, an oxide-based particle model was developed. An HVFAC field test section was also constructed to demonstrate the implementation of a noncontact ultrasonic device for determining the final set time and ideal time to initiate saw cutting. Additionally, a maturity method was successfully implemented that estimates the in-place compressive strength of HVFAC through wireless thermal sensors. An HVFAC mix design procedure using the tools developed in this project such as the calorimeter test, foam index test, and particle-based model was proposed to assist engineers in implementing HVFAC pavements.