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Tytuł:
Adhesion between orthodontic bracket and dental ceramics
Adhezja pomiędzy zamkiem ortodontycznym a ceramiką dentystyczną
Autorzy:
Malkiewicz, Konrad
Krasowski, Michał
Bartczak, Jakub
Radziejewska, Marta
Janas-Naze, Anna
Horodyska, Estera
Powiązania:
https://bibliotekanauki.pl/articles/24202805.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
orthodontics
dental ceramics
adhesive system
shear bonding strength
ortodoncja
ceramika dentystyczna
system adhezyjny
siła połączenia
Opis:
The strength of the connection between orthodontic brackets and sandblasted dental ceramics was evaluated. The strength of the bracket-ceramics connection was determined in four time intervals. Based on the obtained results, basic statistics were calculated. For the comparative analysis of average values, the following were used: ANOVA analysis of variance and Tukey’s HSD post-hoc test at the significance level of α = 0.05. The statistical analysis performed did not show any influence of the method of surface treatment (with sanding, without sanding) between orthodontic brackets and ceramics. At the same time, it has been shown that with samples storing time in aqueous environment, the quality of the connection decreases significantly, regardless of the surface treatment method used.
Zbadano wytrzymałość połączenia zamków ortodontycznych z ceramiką dentystyczną poddaną piaskowaniu. Wytrzymałość połączenia zamek-ceramika wyznaczono w czterech przedziałach czasowych. Do analizy porównawczej wartości średnich zastosowano m.in. analizę wariancji ANOVA oraz test post - hoc Tukeya HSD na poziomie istotności α = 0,05. Przeprowadzona analiza statystyczna nie wykazała wpływu metody obróbki powierzchni porcelany dentystycznej (z piaskowaniem, bez piaskowania) na jakość połączenia zamków ortodontycznych z ceramiką. Jednocześnie wykazano, że wraz z upływem czasu przechowywania próbek w środowisku wodnym, istotnie zmniejsza się jakość połączenia, niezależnie od stosowanej metody obróbki powierzchni.
Źródło:
Polimery; 2023, 68, 7-8; 371--377
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of time-averaged secondary flow cells in wide and narrow straight open channels with lateral bed deformation
Autorzy:
Chattopadhyay, T.
Kundu, S.
Powiązania:
https://bibliotekanauki.pl/articles/38695706.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
turbulent flow
secondary current
method of separation of variable
Reynolds shear stress
Opis:
The usual cellular pattern of the time averaged secondary flow circulation in the central section of wide open channels shows a distorted (laterally or vertically) structure due to the changes in bed configurations along lateral direction. The structures of these secondary circulations (under different bed configurations) are crucial for different types of hydraulic modeling. This study presents mathematical models of the time averaged secondary velocities (lateral and vertical components) for a turbulence-induced secondary current at the central section of a wide open-channel flow under different types of elevated and non-elevated bed conditions. Starting with the Reynolds Averaged Navier-Stokes equation and using the continuity equation, at first the governing equation of secondary flow velocity is obtained including the effects of the eddy viscosity and viscosity of the fluid. The model equations is solved using a separation of the variable technique imposing the bed perturbation condition. Full analytical solutions are achieved through mathematical analysis using suitable boundary conditions consistent with experimental observations. Initially the models are derived for a non-elevated bedforms comprised of alternating equal widths of smooth and rough bed strips. These models are modified further for bedforms with unequal widths of rough and smooth bed strips and elevated periodic bed structures. Four different types of elevated bed configurations are investigated and a general approach is suggested for other types of bed forms. All the proposed models are validated with existing experimental results to ensure the applicability and in each cases, improved results are observed. Obtained results show that the centre of circulation of the cellular structure occurs above the junction of the rough and smooth bed strips (consistent with experimental observations) and it gradually shifts towards the smooth strip, when the length of the rough bed strip is increased. The shifting as a function shows a non-linear pattern with the length of the rough bed strip. A least-square model is proposed to identify the circulation center as a function of the ratio of rough to smooth bed strips. It is also found that the vertically distorted secondary cells are generated when the bed slope strictly increase/decrease throughout the length of the one whole circulation. Finally, all the proposed models are compared with an existing model and an error analysis is done. Results of error analysis show that the present study can be more suitable as it yields improved results.
Źródło:
Archives of Mechanics; 2023, 75, 1-2; 169-211
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the Critical Shear Crack Theory for calculation of the punching shear capacity of lightweight aggregate concrete slabs
Zastosowanie teorii krytycznej rysy ukośnej do określania nośności na przebicie płyt wykonanych z lekkich betonów kruszywowych
Autorzy:
Gołdyn, Michał
Powiązania:
https://bibliotekanauki.pl/articles/2203447.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rozmiar ziaren
przebicie
beton lekki kruszywowy
zazębianie kruszywa
teoria krytycznej rysy ukośnej
punching shear
lightweight aggregate concrete
aggregate interlock
particle size
critical shear crack theory
Opis:
The paper discusses the principles of the Critical Shear Crack Theory (CSCT) in terms of the punching shear analysis of flat slabs made from lightweight aggregate concretes. The basic assumptions of the CSCT were discussed, explaining the differences with regard to the calculation of ordinary concrete flat slabs, relating mainly to the adopted failure criterion associated with ultimate slab rotation. Taking into account the observations and conclusions from the previous experimental investigations, it was confirmed, that contribution of lightweight aggregate particles in the aggregate interlock effect should be ignored, due to possibility of aggregate breaking. However, the analysis of the profile of failure surface confirmed, that particles of the natural fine aggregate increase the roughness of the surface and should be included by formulating failure criterion for LWAC slabs. The theoretical load-rotation relationships were compared with the results of measurements, confirming good agreement in most cases. The theoretical ultimate rotations were lower on average by about 11% than the experimental ones. The analysis of 57 results of the experimental investigations on punching shear of LWAC slabs made from various types of artificial aggregates showed a very good agreement with predictions of the CSCT. The obtained ratio of the experimental to theoretical load was 1.06 with a coefficient of variation of 9.1%. The performed parametric study demonstrated a low sensitivity of the correctness of the CSCT predictions to a change in a fairly wide range of parameters such as: the longitudinal reinforcement ratio, concrete compressive strength and concrete density.
Jednym z podstawowym problemów przy projektowaniu stropów płaskich z lekkich betonów kruszywowych jest zapewnienie odpowiedniej nośności na przebicie stref podporowych. Mimo niewątpliwych zalet, do których można zaliczyć mniejszy ciężar objętościowy czy też lepsze właściwości izolacyjne, lekkie betony kruszywowe charakteryzują się mniejszą o 10 do nawet ponad 30% wytrzymałością na rozciąganie w porównaniu z betonami zwykłymi o zbliżonej wytrzymałości na ściskanie. W odróżnieniu od obowiązującej obecnie normy EN 1992-1-1, bazującej na formułach pół-empirycznych, za podstawę określania nośności płyt na przebicie w procedurach fib Model Code 2010 i prEN 1992-1-1 przyjęto podejście mechaniczne, nawiązujące do Teorii Krytycznej Rysy Ukośnej (Critical Shear Crack Theory - CSCT). Teoria ta zakłada, że wskutek powstania rys ukośnych, mechanizm przenoszenia sił poprzecznych staje się zależny głównie od efektu zazębiania kruszywa, resztkowej wytrzymałości betonu na rozciąganie, oporu ścinania betonu w strefie ściskanej oraz mechanizmu dyblującego zbrojenia głównego. Nośność na przebicie została powiązana ze zdolnością płyty do deformacji, reprezentowanej w przypadku płyt smukłych przez kąt obrotu ψ, który może zostać wyrażony jako całka z krzywizny płyty w rozważanej strefie.
Źródło:
Archives of Civil Engineering; 2023, 69, 1; 55--70
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Behavior study of the steel plate girder with a cellular honeycomb web
Autorzy:
Ammash, Haider K.
Shaffaf, Noora N.
Powiązania:
https://bibliotekanauki.pl/articles/36064862.pdf
Data publikacji:
2023
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
finite element analysis
steel plate girder
honeycomb web
corrugated web
shear strength
web failure
shear stress
numerical analysis
Opis:
Based on the experimental test results of the authors, this investigation is concerned with the finite element analysis to examine and compare the load values and failure modes of the authors’ results. This research was conducted using the Abaqus software. The experimental work included the fabrication of twelve plate girders with honeycomb and flat web plate corrugation patterns, which were then tested under a single concentrated load at the midspan. According to the corrugation dimension or outer honeycomb web thickness, the honeycomb steel plate web girder is divided into three groups (60 mm, 80 mm and 100 mm). The specimens also involved plate girders with a flat web. The specimens were created with three lengths (600 mm, 1,200 mm and 1,800 mm). The Abaqus software was used in finite element models to simulate the concentrated load. The numerical results demonstrated that the 60 mm thick honeycomb web provides a greater load-bearing capacity and shear strength than other girders. The 20 mm honeycomb corrugation on the steel plate girder indicates the increased and improved shear resistance. The conclusion was that as the width of the corrugation increased, so did the steel web’s ultimate load and shear strength, resulting in a positive relationship between the critical shear buckling load of the web and the moment of inertia at the strong axis. When the dimension of the corrugation increases, the moment of inertia of the Y axis (Iy) decreases; thus, the plate girder will fail with a less critical buckling load (Pcr). Also, it can be concluded that as the steel plate thickness of the honeycomb web increases, the shear resistance increases as well. However, the spacing between the intermediate stiffener or the horizontal spacing of the web panel can enhance the shear resistance of honeycomb web girder if it was decreased due to increasing the action of tension field force that resists the diagonal tension developed at the web panel by the applied midspan concentrated force.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2023, 32, 2; 101-116
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comprehensive system for simulation of vibration processes during the titanium alloys machining
Autorzy:
Stupnytskyy, Vadym
Xianning, She
Novitskyi, Yurii
Novitskyi, Yaroslav
Powiązania:
https://bibliotekanauki.pl/articles/27309878.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
titanium alloys
cutting dynamic
simulation
adiabatic shear
finite element analysis
stopy tytanu
dynamika skrawania
symulacja
analiza elementów skończonych
Opis:
Titanium alloys are difficult-to-machine materials due to their complex mechanical and thermophysical properties. An essential factor in ensuring the quality of the machined surface is the analysis and recommendation of vibration processes accompanying cutting. The analytical description of these processes for machining titanium alloys is very complicated due to the complex adiabatic shear phenomena and the specific thermodynamic state of the chip-forming zone. Simulation modeling chip formation rheology in Computer-Aided Forming systems is a practical method for studying these phenomena. However, dynamic research of the cutting process using such techniques is limited because the initial state of the workpiece and tool is a priori assumed to be "rigid", and the damping properties of the fixture and machine elements are not taken into account at all. Therefore, combining the results of analytical modeling of the cutting process dynamics with the results of simulation modeling was the basis for the proposed research methodology. Such symbiosis of different techniques will consider both mechanical and thermodynamic aspects of machining (specific dynamics of cutting forces) and actual conditions of stiffness and damping properties of the “Machine-Fixture-Tool-Workpiece” system.
Źródło:
Archive of Mechanical Engineering; 2023, LXX, 1; 85--105
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystal Lattice Rotations Induced by Shear Banding in fcc Metals Deformed at High Strain Rates
Autorzy:
Mania, Izabela
Paul, Henryk
Chulist, Robert
Petrzak, Paweł
Miszczyk, Magdalena
Prażmowski, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/2203719.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
shear bands
high strain rates
texture
SEM/EBSD
Opis:
In this paper, the microstructural and texture changes in polycrystalline CuZn30 alloy, copper, and AA1050 aluminium alloy have been studied to describe the crystal lattice rotation during shear bands formation. The hat-shaped specimens were deformed using a drop-hammer at the strain rate of 560 s-1. Microstructure evolution was investigated using optical microscopy, whereas texture changes were examined with the use of a scanning electron microscope equipped with the EBSD facility. The microstructural observations were correlated with nanohardness measurements to evaluate the mechanical properties of the sheared regions. The analyses demonstrate the gradual nature of the shear banding process, which can be described as a mechanism of the bands nucleation and then successive growth rather than as an abrupt instability. It was found that regardless of the initial orientation of the grains inside the sheared region, a well-defined tendency of the crystal lattice rotation is observed. This rotation mechanism leads to the formation of specific texture components of the sheared region, different from the one observed in a weakly or non-deformed matrix. During the process of rotation, one of the {111} planes in each grain of the sheared region ‘tends’ to overlap with the plane of maximum shear stresses and one of the <110> or <112> directions align with the shear direction. This allows slip propagation through the boundaries between adjacent grains without apparent change in the shear direction. Finally, in order to trace the rotation path, transforming the matrix texture components into shear band, rotation axis and angles were identified.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 319--329
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic Test and Analysis of Strength of Bamboo Curtain Plywood Based on Free Vibration Modal Method
Autorzy:
Gu, Xiaoyu
Zhou, Aijin
Adjei, Patrick
Zhang, Rongzhuo
Zhou, Yuhao
Wang, Zheng
Powiązania:
https://bibliotekanauki.pl/articles/29433299.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
Tematy:
bamboo wood
plywood
elastic modulus
shear modulus
Poisson's ratio
dynamic test
Opis:
Bamboo curtain plywood is made of equal-thickness slotted bamboo slivers as its constituent units and is formed into boards with high pressure. In this paper, rectangular plates, beam specimens, and two sizes of square plates were tested to determine the elastic modulus and shear modulus of bamboo curtain plywood quickly, easily, and accurately. The free square board torsional vibration method was used to test the shear modulus of the square plates. The dynamic test results were also verified by means of the static four-point bending method. The main conclusions show that the dynamic elastic modulus, shear modulus and Poisson's ratio of this bamboo curtain plywood are 0.7 GPa, 1300 MPa and 0.12, respectively. The values of the elastic constants of these bamboo curtain plywood specimens measured by dynamic and static methods are consistent, and this dynamic test method has the advantages of fast, easy, good repeatability and high accuracy.
Źródło:
Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2023, 66, 212; Art. no. 176766
1644-3985
Pojawia się w:
Drewno. Prace Naukowe. Doniesienia. Komunikaty
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of hybrid steel-polypropylene fiber on punching shear behavior of flat slab with an opening
Autorzy:
Zaezue, Shahzinan J.
Hadi, Waleed K.
Powiązania:
https://bibliotekanauki.pl/articles/36060590.pdf
Data publikacji:
2023
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
hybrid fiber
steel fiber
polypropylene fibre
punching shear
slab with opening
Opis:
This research aimed to gain a better understanding of how the addition of fiber influences the punching shear capacity of two-way slabs by conducting an experiment into the structural behavior of flat slabs with and without a square opening using different volume fractions of hybrid steel-polypropylene fiber (0%, 0.9%, 1.05% and 1.8%). Ten 700 × 700 × 70 mm slabs were divided into five pairs, with two samples used as control samples (with and without openings), and eight other samples with different volume fraction of fibers. Results showed that an increase in fiber content enhanced the shear strength of the slabs. For example, as the volume fraction of hybrid fiber increased from 0.0 to 1.8%, the ultimate load increased by 52% for slabs without an opening and up to 42% for slabs with an opening.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2023, 32, 1; 3-17
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of nanosilica stabilisation on the bearing capacity under undrained conditions
Wpływ stabilizacji nanokrzemionką na nośność podłoża gruntowego w warunkach bez odpływu
Autorzy:
Tankiewicz, Matylda
Mońka, Jakub
Zięba, Zofia
Powiązania:
https://bibliotekanauki.pl/articles/27312167.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
nanokrzemionka
wytrzymałość na ścinanie bez odpływu
ściskanie jednoosiowe
nośność podłoża
ława fundamentowa
nanosilica
undrained shear strength
unconfined compression
bearing capacity
strip footing
Opis:
Due to the increasing necessity of building on soils with insufficient bearing capacity, the development of methods for soil improvement is an important geotechnical engineering issue. One of the innovative methods of soil stabilisation is the use of nano-additives. The paper presents the influence of nanosilica on the bearing capacity under the footing under undrained conditions. For this purpose, a simple and quick unconfined compression test was used to evaluate the undrained shear strength of selected silty soil. Tests were conducted for soil without additives and with nanosilica contents of 1, 3 and 5%. All samples were compacted to the maximum dry density in a Proctor apparatus, and strength tests were conducted after 7 days of curing. The results clearly show an increase in undrained shear strength with increasing nanosilica content. Based on these data, a parametric analysis of the bearing capacity under the strip footing was performed for 4 variants of nanosilica content and for 9 loading cases. Thus, the impact of stabilisation in a practical engineering issue was presented. For all load cases the optimal dimensions of the foundation were determined. In addition, for the selected case, calculations were made for a fixed foundation dimension. All computations were performed in accordance with Eurocode 7 with GEO5 software.
Ze względu na coraz powszechniejszą konieczność posadawienia obiektów na gruntach o niewystarczającej nośności, rozwój metod ulepszania i stabilizacji podłoża gruntowego jest aktualnym wyzwaniem inżynierii geotechnicznej. Jedną z innowacyjnych metod stabilizacji gruntu jest wykorzystanie nanododatków jako materiału stabilizującego. Zaletami tego rozwiązania są mniejsza ilość dodatku wymagana do uzyskania określonej poprawy właściwości mechanicznych gruntu względem tradycyjnych metod oraz mniejszy negatywny wpływ na środowisko. W kontekście ulepszenia podłoża gruntowego nanododatkami wybór nanokrzemionki (nano SiO2) stanowi optymalne rozwiązanie z punktu widzenia skuteczności i kosztów. W pracy przedstawiono wpływ zawartości nanokrzemionki na nośność podłoża pod ławą fundamentową w warunkach bez odpływu. W praktyce warunki te występują przede wszystkim w sytuacjach przejściowych, gdy następuje szybki przyrost obciążeń. W pierwszej kolejności wykonano badania laboratoryjne mające na celu określenie parametrów wytrzymałości wybranego gruntu bez dodatku oraz stabilizowanego nanokrzemionką. W tym celu wykorzystano prosty i szybki test jednoosiowego ściskania pozwalający na ocenę wytrzymałości gruntu w warunkach bez odpływu. Badania laboratoryjne wykonano dla wybranego gruntu pylastego. Testy przeprowadzono dla czystego materiału gruntowego oraz z dodatkiem nanokrzemionki 1, 3 i 5%. Wszystkie próbki zostały zagęszczone do maksymalnej gęstości objętościowej szkieletu gruntowego w aparacie Proctora a testy wytrzymałościowe przeprowadzono po 7 dniach dojrzewania próbek. Badania wykazały średni wzrost wytrzymałości na ścinanie bez odpływu Cu odpowiednio o 18.1%, 54.9% i 76.0% w porównaniu do gruntu bez dodatku. Zaobserwowano również znaczny wzrost modułu siecznego Eu50 tj. odpowiednio 29.7%, 111.0% i 120.1%. W przypadku wytrzymałości stwierdzono liniową zależność wytrzymałości od zawartości nanokrzemionki. Dla sztywności ta zależność była inna, jednak ze względu na duży rozrzut wyników nie można było sformułować jednoznacznych wniosków. Otrzymane dane znacznie odbiegają od tych prezentowanych w literaturze dla podobnych typów gruntów i zawartości nanokrzemionki, co prawdopodobnie spowodowane jest innymi czynnikami wpływającymi na wyniki badań.
Źródło:
Archives of Civil Engineering; 2023, 69, 3; 269--284
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Contamination with Gasoline and Diesel Oil on Shear Strength of Coarse Grained Soil
Autorzy:
Brzeziński, Bartłomiej
Olchawa, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/27315755.pdf
Data publikacji:
2023
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
motor fuels
coarse-grained soil
shear strength
direct shear tests
Opis:
he paper presents research results into the influence of motor fuels on the shear strength of coarse-grained soil. The soil was classified following the unified soil classification system PN-EN ISO 14668-1 as saGr. The soil samples were artificially contaminated with three percentage ratios of motor fuels 5, 7.5 and 10% in relation to the dry mass of the soil skeleton. The test results have shown that motor fuel contamination significantly impacts the tested soil's mechanical properties. Increasing the content of impurities causes a significant decrease in shear strength parameters. For soil contaminated with 5%, 7.5% and 10% of motor fuel, i.e. gasoline or diesel, the angle of internal friction decreased by 8%, 15% and 20%, respectively. Along with the impurities increase, the soil's ultimate bearing capacity, calculated following EC-7, showed a dramatic decrease. The decrease was 40%, 57% and 66% respectively.
Źródło:
Rocznik Ochrona Środowiska; 2023, 25; 222--227
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of fundamental elastic wave modes coupling in composite plates
Autorzy:
Barski, Marek
Stawiarski, Adam
Chwał, Małgorzata
Augustyn, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/24201983.pdf
Data publikacji:
2023
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
shear horizontal wave mode
symmetric wave mode
dispersion curves
finite element method
fala SH
fala symetryczna
krzywa dyspersji
metoda elementów skończonych
Opis:
In the case of the piezoelectric actuators of the cube-shaped installed symmetrically and perfectly bonded on both external surfaces of the plate-like structures, the symmetric and shear horizontal elastic wave modes are excited at the same time. The current work concerns the numerical simulation of the coupling of the above-mentioned elastic wave modes in a composite plate of angle ply configuration. In the first step, the dispersion curves for all studied composite configurations are estimated. Next, for the arbitrary chosen fixed frequency of the excitation, finite element simulations are performed. As a result of these simulations, the group velocities of the observed elastic modes are estimated. Next, the appropriate wave modes are identified by the comparison of the group velocities obtained from the analysis of the dispersion curves and from the simulations. In the cases for which the identification is possible, a good agreement between analytical and simulation results is observed.
Źródło:
Vibrations in Physical Systems; 2023, 34, 1; art. no. 2023120
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on creep-fatigue model of anchored jointed rock mass
Autorzy:
Song, Yang
Fan, Bo
Li, Yong-Qi
Wang, He-Ping
Powiązania:
https://bibliotekanauki.pl/articles/2200878.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
shear creep
anchored jointed rock mass
fractional order
fatigue load
damage
Opis:
To explore the mechanical response of anchored rock mass with an interaction of fatigue and creep, this paper selects the fatigue amplitude and fatigue frequency as influencing factors to carry out a fatigue-creep experiment of the anchored rock mass. Based on fractional order theory and binary perturbation theory, a new fractional order creep model is constructed. The results show that compared with the Burgers model, the newly proposed creep model can better describe the whole process of creep deformation of the anchored jointed rock mass under fatigue loading.
Źródło:
Journal of Theoretical and Applied Mechanics; 2023, 61, 1; 163--173
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rheological behavior of polymer-based drilling fluids: experimental study of temperature effects
Autorzy:
Safi, Brahim
Aboutaleb, Djamila
Haider, Soumya
Powiązania:
https://bibliotekanauki.pl/articles/45423959.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
polimery
naprężenie
lepkość
reologia
polymers
methylcellulose carboxylate
drilling fluid
shear stress
viscosity
rheological behavior
Opis:
Drilling fluids most commonly used are generally based on polymers. Polymers such as methylcellulose carboxylate (CMC), polyanionic cellulose (PAC) and xanthan (Xn) have a very important role in the success of drilling operations. Indeed, they are also used to improve certain properties, in particular rheological. However, these polymers can lose their characteristics under the influence of increasing temperature at the bottom of oil wells, thus affecting the ability of the mud to perform its useful role in the drilling operation, namely to raise the cuttings from the bottom of the well to the surface. The present work aims to study the effect of temperature on the main rheological properties (shear stress and plastic viscosity) as well as on the rheological behavior of water-based drilling muds (WBM). WBM_CMC and WBM_PAC (at Xn content fixed) were selected to evaluate the temperature effect (20°C; 40°C; 60°C and 80°C) on the rheological parameters and the rheological behavior. The results revealed that the shear stress and the plastic viscosity of the studied muds were considerably affected by an increase in temperature. A significant decrease in these drilling mud parameters as a function of temperature up to 80°C. A reduction of 58.8% in shear stress and 78.5% in plastic viscosity was observed. The results show that regardless of the test temperature, the shear thinning behavior of the WBM_CMC and WBM_PAC drilling muds is the same as the Herschel-Bulkley model.
Źródło:
International Journal of Applied Mechanics and Engineering; 2023, 28, 1; 95-104
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shear properties of a honeycomb structure with zero Poisson’s ratio
Autorzy:
Song, L.
Sun, Y.
Han, Z.
Wang, T.
Wang, H.
Yin, C.
Shen, X.
Powiązania:
https://bibliotekanauki.pl/articles/38697109.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
honeycomb structure
zero Poisson’s ratio
shear properties
small deformation
large deformation
Opis:
Honeycomb structures with zero Poisson’s ratio show promising potential for application in variable-sweep wing aircraft. The shear properties of these honeycomb structures serve as a crucial indicator of their morphing capacity. This paper derives the linear and non-linear shear properties of a honeycomb structure with zero Poisson’s ratio. A modified factor is introduced to establish a relationship between the linear and non-linear shear modulus of the honeycomb structure, simplifying the calculation method of the non-linear shear modulus. The validity of theoretical predictions is then confirmed using the finite element method Furthermore, the influences of the geometric parameters on the shear properties of the honeycomb structure with zero Poisson’s ratio are investigated, highlighting the varying contributions of these cell geometric parameters to the shear properties.
Źródło:
Archives of Mechanics; 2023, 75, 5; 521-541
0373-2029
Pojawia się w:
Archives of Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shear Strength of Soil-Root Layer Formed on Degraded Soil Supplemented with New Zeolite Substrate
Autorzy:
Chomczyńska, Mariola
Franus, Małgorzata
Żukowska, Grażyna
Powiązania:
https://bibliotekanauki.pl/articles/27323839.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
degraded area
shear strength
zeolite substrate
landslide
Opis:
The aim of the study was to determine the shear strength of the soil-root layer obtained as a result of growth of cocksfoot (Dactylis glomerata L.) on degraded soil enriched with the addition of a new zeolite substrate Z-ion. Measurement of shear strength for soil-root layers formed as a result of growth of a grass species (on degraded soil alone and on degraded soil with added Z-ion) was performed in a direct shear apparatus. The measurement results allowed determining parameters of equations describing the dependence of shear strength of studied soil-root layers on normal stress e.g. cohesion and internal friction coefficient. Under the experimental conditions, application of 1% v/v substrate addition to degraded soil induced development of cocksfoot root system which resulted in the significantly increased cohesion of soil-root layer (by 30%) as compared to that formed on degraded soil alone. The enhanced cohesion of the soil-root layer formed on soil enriched with Z-ion resulted in its significantly increased shear strength as compared to that of soil-root layer obtained on soil alone. Further research using higher doses of the Z-ion substrate (greater than 1% v/v) is needed to obtain the information at what dose ranges of the substrate one can expect even more intensive development of plant root systems and, consequently, further significant improvement in the shear strength of the soil-root layers.
Źródło:
Journal of Ecological Engineering; 2023, 24, 7; 128--134
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 535

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