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1

Experimental study of nanocomposite hybrid adhesive-rivet joints

Nabibi Nabard, Ramezani Shadi

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

337--365

EN

The wide range of rivets usage goes back to the processes of manufacturing and repairing an aircraft fuselage. When it comes to structural joints, adhesive bonding is said to have some merits which overshadow other joining methods, such as bolting, riveting, and welding. Today, the applications of structural adhesives do not end in aerospace, but they also are ideal for the automotive industry, where the need is to join plates of dissimilar adhesives to produce lightweight car bodies. The hybrid joints also are one of the methods of joining different parts of the machine in a durable way in which some benefits such as the significant tensile strength, the dissipated energy, and higher reliability during long-term working stand out. In this research, the effect of rivets layout on strength and failure of nanocomposite rivet and hybrid adhesive-rivet joints through two experimental and numerical methods was evaluated. Also, using the artificial neural networks method, force–displacement curves for specimens were obtained. The results of the experimental tests and the finite element analysis showed that as the number of rivets increased in the joint of the nanocomposite components, the strength of the joint increased. The layout of the rivets has a significant effect on the strength of the rivet joint. According to the performed experiments for achieving the efficient strength in the hybrid joints for the nanocomposite plates, since the strength of the adhesive is very effective, adhesive selection and the appropriate number of rivets are the key factors. The fracture modes in the internal plates of nanocomposite joints (adhesive, rivet, and adhesive-rivet joints) were observed as follows: net-tension, bearing, shear-out, crack propagation, tearing, and shear in adhesive layers. Besides, the numerical model of the work is done using ABAQUS software. The results of software simulation in the numerical model are compatible with the experimental method’s findings. However, the agreement between the results of experimental and neural network methods is higher. Owing to the results of experiments, the polypropylene nanocomposite as well as the appropriate jointing method can be put forward in the structures of the automotive industry.

2

Influence of Humidity on the Energy of Specific Strain in the Process of Loading Sedimentary Rocks

Bukowska Mirosława, Smolorz Anna

Studia Geotechnica et Mechanica

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2019

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Vol. 41, nr 4

223--230

EN

This article presents the results of tests on the energy properties of sedimentary rocks in the Upper Silesian Coal Basin. The rocks were tested both in an air-dry state and in a water saturation state. Samples of sedimentary rocks were collected from boreholes drilled in the underground workings of coal mines located within the area of the city of Jastrzębie, in the areas of the Chwałowice Trough and Rybnik Trough (south-western part of the Upper Silesian Coal Basin) and in the Main Trough. Influence of saturation condition on the values of the tested energy parameters was observed. The values of elastic energy and dissipated energy obtained for the samples tested in water saturation were lower compared to the values obtained for samples tested in air-dry state. As observed, an increase in the values of the given types of specific energy corresponds to an increase in the uniaxial compression strength in air-dry state and in water saturation state. Results of the tests are original and they can be applied while analysing the possibility of the occurrence of some dynamic phenomena and hazards in mine workings in Carboniferous rock mass in the Upper Silesian Coal Basin, caused by mining operations.

3

Experimental and numerical study on seismic behavior of LYS and HYS steel plate shear walls connected to frame beams only

Shekastehband B., Azaraxsh A., Showkati H.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 1

154--168

EN

This paper presents an experimental and numerical investigation on the steel plate shear walls with beam-only-connected web plates (SSW-BO). These systems feature an alternative to the traditional type of steel shear walls through separating the lateral load resisting system from the primary columns. A possible drawback of SSW-BO is its reduced shear capacity compared with fully-connected web plates. High yield strength (HYS) web plate may develop shear capacity of these systems. The seismic behavior of the SSW-BO systems are experimentally investigated under cyclic quasi-static loading and compared considering two material properties and two different circular opening ratios. Shear strength, ductility, and energy dissipation capacity of HYS panels are higher than those of low yield strength (LYS) panels by as much as roughly 70%, 10% and 30%, respectively. The use of HYS web plates in SSW-BO systems appeared to be a promising solution to compensate the concerns regarding the low shear capacity and low energy dissipation resulting from separation steel plate from the columns. Moreover, the finite element software ABAQUS was used to investigate the behavior of SSW-BO systems by nonlinear analysis. A comparison between the experimental and numerical results showed excellent agreement.

4

Experimental investigation of an automotive magnetorheological shock absorber

Jastrzębski Ł., Sapiński B.

Acta Mechanica et Automatica

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2017

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Vol. 11, no. 4

253--259

EN

The study summarises the experimental examination of an automotive magnetorheological (MR) shock absorber under electrical and mechanical excitations, investigates its current and force responses and the energy dissipation in the system. The aim of experiments was to acquire measurement data that allows in next step of the research program to engineer an energy harvesting device for the absorber. The work covers basic technical data of the absorber, description of the experimental set-up, scenario of testing program and test results of the device. Of particular importance is the influence the operating current, piston displacement amplitude and piston velocity have on the absorber’s response.

5

Specific energy of hard coal under load

Bogusz A., Bukowska M.

Studia Geotechnica et Mechanica

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2015

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Vol. 37, nr 1

9--16

EN

The article presents results of experimental tests of energy parameters of hard coals under loading, collected from research sites located within five main geologic structures of Upper Silesian Coal Basin (GZW) – Main Trough, Main Anticline, Bytom Trough, Rybnik Trough and Chwałowice Trough. Coals from12 mines were analysed, starting with seams of group 200, through groups 400, 500, 600 and, finally, seams of group 700. Coal of each of the groups of seams underwent uniaxial compression stress of the energy parameters, in a servo-controlled testing machine MTS-810NEW, for the full range of strain of the tested coal samples. Based on the tests the dependence of different types of specific energy of longitudinal strain of coals on the value of uniaxial compression strength was determined. The dependence of the value of dissipated energy and kinetic energy of coals on the uniaxial compression strength was described with a linear function, both for coals which due to their age belong to various bed sand for various lithotypes of coal. An increase in the value of dissipated energy and in kinetic energy was observed, which was correlated with an increase in uniaxial compression strength of coal. The share of dissipated energy is dominant in the total energy of strain. Share of recoverable energy in the total energy of strain is small, independent of the compression strength of coals and is at most a few per cent high. In coals of low strength and dominant share of dissipated energy, share of recoverable energy is the biggest among the tested coals. It was shown that following an increase in compression strength the share of recoverable energy decreases, while the share of dissipated energy in the total energy increases. Further studies of specific energy of longitudinal strain of rocks in the full-range strain will be the next step inperfecting methodology of research into natural rock burst susceptibility of Carboniferous rock mass and changes in the susceptibility resulting from mining activity.

6

Spinal sections and regional variations in the mechanical properties of the annulus fibrosus subjected to tensile loading

Żak M., Pezowicz C.

Acta of Bioengineering and Biomechanics

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2013

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Vol. 15, no. 1

51--59

EN

The annulus fibrosus is the primary load-bearing component of the intervertebral disc responsible for proper transfer of loads in the spine. The aim of this study was to determine selected mechanical parameters of multilayer specimens of the annulus fibrosus of the intervertebral disc during uniaxial tensile loading. The anatomical location (anterior/posterior) of the test specimens of the annulus fibrosus and its location along the length of the spine were analysed to determine their impact on the maximum failure force, stiffness, the value of Young’s modulus and dissipated energy. The results indicated high energy losses over the five consecutive precondition loops while the value of the force remained at a constant level. The thoracic and lumbar specimens showed the highest values of the parameters analysed. There were also significant changes depending on the anatomical region of the intervertebral disc, where anterior specimens demonstrated higher mechanical values compared to posterior specimens.

7

Energia dyssypacji w kompozytach napełnianych włóknem szklanym i napełniaczem mineralnym

Mazurkiewicz S., Porębska R., Żmudka S.

Zeszyty Naukowe Politechniki Poznańskiej. Budowa Maszyn i Zarządzanie Produkcją

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2010

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Nr 12

237-240

PL

W pracy przedstawiono wyniki badań energii dyssypacji dla kompozytów na osnowie poliacetalu i polipropylenu z napełniaczem włóknistym i mineralnym. Właściwości mechaniczne kompozytów są powiązane z wartością energii dyssypacji oraz charakterystykami pętli histerezy. Poznanie tych zależności pozwoli na ocenę właściwości mechanicznych kompozytów w ich czasie eksploatacji, oraz może być pomocne w poszukiwaniu optymalnych parametrów ich przetwórstwa.

EN

There is a relationship beetwen the value of energy dissipation and characteristics of hyster loop during the first loading cycles and mechanical properties of composites. The ability to mr stand these relationships let us evaluate mechanical features of composites during exploitation can be helpful while searching for optimal parameters of their processing.

8

Energia dyssypacji w kompozytach polimerowych

Porębska R., Mazurkiewicz S.

Czasopismo Techniczne. Mechanika

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2009

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R. 106, z. 1-M

245-248

PL

Istnieje związek pomiędzy wartością dyssypacji energii i charakterystykami pętli histerezy w pierwszych cyklach obciążeń a właściwościami mechanicznymi kompozytów. Poznanie tych zależności pozwoli na ocenę właściwości mechanicznych kompozytów w ich czasie eksploatacji, oraz może być pomocnym w poszukiwaniu optymalnych parametrów ich przetwórstwa.

EN

There is a relationship beetwen the value of energy dissipation and characteristics of hysteresis loop during the first loading cycles and mechanical properties of composites. The ability to understand these relationships let us evaluate mechanical features of composites during exploitation and can be helpful while searching for optimal parameters of their processing.

9

Inteligentny autonomiczny system elektroenergetyczny integrujący rozproszone źródła i zasobniki energii odnawialnej

Nowakowski A., Lisowiec A., Kołodziejczyk Z.

Nowa Elektrotechnika

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2008

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nr 6 (46)

40--47

10

Tribologiczne konsekwencje segregacji powierzchniowej alifatycznych alkoholi z wulkanizatów kauczuku butadienowo-styrenowego

Głąb P., Bieliński D.M.

Tribologia

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2005

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nr 1

37-54

PL

Artykuł dotyczy wpływu zjawiska segregacji powierzchniowej małocząsteczkowych składników mieszanki na charakterystykę tribologiczną gumy. Segregacja powierzchniowa alkoholi alifatycznych (od dodekanolu aż do dokozanolu) w nadtlenkowych wulkanizatach kauczuku butadienowo-styrenowego (SBR) była badana za pomocą spektroskopii w podczerwieni, wykorzystującej całkowite wewnętrzne odbicie (FTIR-IRS). Kinetyki migracji obliczano na podstawie widm FTIR, stosując metodę elementów skończonych, zaproponowaną wcześniej do analizy zjawiska dyfuzji [L. 7]. Z przeprowadzonych badań wynika, że szybkość wykwitania alkoholu wzrasta wraz ze wzrostem liczby atomów węgla obecnych w jego cząsteczce, osiągając maksimum dla pentadekanolu, po czym obniża się. Wzrost szybkości migracji małocząsteczkowego dodatku w SBR jest związany z obniżeniem się granicy jego rozpuszczalności w kauczuku, który wynika ze wzrostu długości łańcucha alifatycznego. Ten ostatni jest odpowiedzialny za obniżoną mobilność cząsteczek alkoholi w kauczuku. Obniżenie granicy rozpuszczalności sprzyja wzrostowi siły napędowej dyfuzji, podczas gdy obniżenie ruchliwości cząsteczek powoduje efekt odwrotny. Zaprezentowano metodę analizy energii rozpraszanej w procesie tarcia przez materiał próbki, opartą na uproszczonym modelu sprężyny. Metoda nie umożliwia dokładnego obliczenia ilości energii rozproszonej w badanym materiale podczas testu tarcia. Dostarcza natomiast informacji na temat strat energetycznych, które można zastosować w celu porównania materiałów. Współczynnik tarcia wułkanizatów SBR maleje wraz ze wzrostem grubości wykwitów alkoholi alifatycznych, co jest przejawem zjawiska smarowania. Jeśli smarowanie jest efektywne, umożliwia znaczne obniżenie składowej histerezyjnej siły tarcia. Jednakże, jeśli wykwit uformowany na powierzchni wulkanizatu nie jest wystarczająco gruby, aby wyeliminować odkształcenia objętościowe, tarcie materiału może wzrosnąć w wyniku plastyfikacji matrycy kauczuku. Oznacza to, że segregacja powierzchniowa powoduje również zmianę właściwości objętościowy wulkanizatu SBR, która jest konsekwencją istnienia powierzchniowego gradientu stężenia alkoholu w matrycy kauczuku. Jego obecność może w znaczący sposób wpływać na zachowanie się gumy w procesie tarcia.

EN

Paper concerns an influence of the surface segregation of low molecular weight components of rubber mix on tribological characteristic of vulcanisates. The surface segregation of aliphatic alcohols (from dodecanol up to docosanol) from peroxide vulcanisates of styrene-butadiene rubber (SBR) was investigated by infrared internal reflection spectroscopy (FTIR-IRS). Kinetics of migration were calculated from FTIR data, applying a final element method, formely used for analysis of diffusion phenomenon in rubber [L. 7]. From results obtained it follows that blooming rate of alcohol increases with an increase of carbon atoms present in its molecule, reaching maximum for pentadecanol, and afterwards decreases. The increase of migration rate is a result of decrease of its solubility limit in rubber with an increase of aliphatic chain length. The latter is responsible for a decrease of mobility of alcohol molecules in rubber. A decrease of the solubility limit facilitates an increase of a driving force for diffusion, whereas a decrease of molecules mobility causes an opposite effect. Method for energy dissipation analysis during friction, based on a simplified spring-like model, has been presented. The method does not allow to calculate an exact amount of energy dissipated in a material studied during friction test. However, it provides a useful parameter of energy lost, applicable for samples comparison. The coefficient of friction of SBR vulcanisates decreases with an increase of an alcohol bloom thickness, what is the result of lubrication phenomenon. If solid lubrication of alcohol is efficient the hysterical component of friction force could be significantly reduced. However, if an alcohol bloom being formed on the surface of vulcanisate is not thick enough to eliminate bulk deformations of the material, friction can be higher due to plastification of the rubber matrix. It means that the surface segregation causes also changes to the bulk properties of SBR vulcanisates, being the result of the surface gradient of alcohol concentration in the rubber matrix. Its presence can strongly influence tribological performance of the rubber sample.

11

Renewable energy sources

Mazurek B.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2005

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Vol. 42, nr 16

5-8

EN

Burning of coal in energy production causes a considerable degradation of natural environment, hence a tendency occurs to move over to less harmful energy sources - gas, crude oil and biomass. Renewable clean energy sources, such as water power, wind and solar energy gain on importance, and their share in overall energy balance must constantly increase. A new philosophy of the development of power industry is represented by the so called distributed (decentralized) power industry, consisting of a number of small power plants localized near and user. In the nearest future an urgent need will emerge for mobile power units with several to some dozen of megawatts output, mounted on trucks. These units will be used in case of disasters and failures of power nets.

12

Renewable energy sources

Mazurek B.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2003

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Vol. 39, nr 14

5-8

EN

Burning of coal in energy production causes a considerable degradation of natural environment, hence a tendency occurs to move over to less harmful energy sources - gas, crude oil and biomass. Renewable clean energy sources, such as water power, wind and solar energy gain on importance, and their share in overall energy balance must constantly increase. A new philosophy of the development of power industry is represented by the so called distributed (decentralized) power industry, consisting of a number of small power plants localized near and user. In the nearest future an urgent need will emerge for mobile power units with several to some dozen of megawatts output, mounted on tracks. These units will be used in case of disasters and failures of power nets.