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Tytuł:
Study on the influence of chamfer perforation on heave and pitch of a single floating platform
Autorzy:
Wang, Wei
Fan, Sheming
You, Yunxiang
Zhao, Cheng
Xu, Liqun
Wang, Guibiao
Lu, Zhiqiang
Powiązania:
https://bibliotekanauki.pl/articles/32915201.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
single floating wind power platform
different chamfered perforation
numerical simulation
experiment
heave plate
Opis:
The aim of this work is to study the influence of chamfered perforation and chamfering on the heave and pitch motion of a single floating wind power platform with an anti-heave device. Firstly, the hydrodynamic performance of a single floating body with different chamfers, or without perforation, is calculated and analysed. Secondly, the motion of a model without perforation and with 35° chamfered perforation is captured and studied in a towing tank. The results show that when the wave height is large and the period is small, the perforated device has a certain effect. When the wave height and period are small, the pitch suppression effect of chamfered perforation is more obvious than that of non-chamfered perforation. When the period and wave height are large, the heave suppression effect of non-chamfered perforation is better than that of chamfered perforation. In experimental research, the perforated floating body has a certain effect on restraining the heave and pitch of a floating body under most working conditions, and the effect of restraining the pitch is obviously better than that of restraining the heave.
Źródło:
Polish Maritime Research; 2023, 1; 43-53
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations on pool boiling of refrigerant R141b outside a horizontal tube
Autorzy:
Baki, Touhami
Aris, Abdelkader
Tebbal, Mohamed
Powiązania:
https://bibliotekanauki.pl/articles/1845055.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
horizontal tube
experiment
correlation
CHF
simulation
rura pozioma
eksperyment
korelacja
symulacja
Opis:
Boiling produces vapor with a phase change by absorbing a consistent amount of heat. Experimentation and modeling can help us better understand this phenomenon. The present study is focused on the heat transfer during the nucleate pool boiling of refrigerant R141b on the surface of a horizontal copper tube. The results of the experiment were compared with four correlations drawn from the literature, and the critical heat flux was examined for different pressures and also compared with the predicted values. Simulating boiling with two-phase models allowed us to infer the plot of the temperature distribution around the tube and compared it to results from other work.
Źródło:
Archive of Mechanical Engineering; 2021, LVIII, 1; 77-92
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study on the optimization of hydrodynamic performance of oscillating buoy wave energy converter
Autorzy:
Lai, Wenbin
Xie, Yonghe
Li, Detang
Powiązania:
https://bibliotekanauki.pl/articles/1573638.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
wave energy converter
hydrodynamic performance
numerical simulation
physical experiment
Opis:
The oscillating buoy wave energy converter (OBWEC) captures wave energy through the undulating movement of the buoy in the waves. In the process of capturing wave energy, the hydrodynamic performance of the buoy plays an important role. This paper designed the “Haida No. 1” OBWEC, in which the buoy adopts a form of swinging motion. In order to further improve the hydrodynamic performance of the buoy, a 2D numerical wave tank (NWT) model is established using ADINA software based on the working principle of the device. According to the motion equation of the buoy in the waves, the influence of the buoy shape, arm length, tilt angle, buoy draft, buoy width, wave height and Power Take-off (PTO) damping on the hydrodynamic performance of the buoy is studied. Finally, a series of physical experiments are performed on the device in a laboratory pool. The experimental results verify the consistency of the numerical results. The research results indicate that the energy conversion efficiency of the device can be improved by optimizing the hydrodynamic performance of the buoy. However, the absorption efficiency of a single buoy for wave energy is limited, so it is very difficult to achieve full absorption of wave energy.
Źródło:
Polish Maritime Research; 2021, 1; 48-58
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using FORDRY model to forecast transformation of Norway spruce (Picea abies (L.) Karst.) stands in Nadsyansky Regional Landscape Park (Ukrainian Carpathians)
Autorzy:
Kozak, Ihor
Parpan, Taras
Shparyk, Yuriy
Mylenka, Myroslava
Kozak-Balaniuk, Iryna
Powiązania:
https://bibliotekanauki.pl/articles/2041033.pdf
Data publikacji:
2021
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
spruce forest decline
tree biomass
tree number
species composition
prediction
simulation experiment
gap model
Opis:
The aim of this study was to simulate transformation of species composition, biomass and number of treesin spruce stands depending on a possible combination of cutting and planting scenarios as well as climate changes. The FORDRY computer model was used to predict the dynamics of Norway spruce (Picea abies (L.) Karst.) stands in Nadsyansky Regional Landscape Park in the Ukrainian Carpathians. Potential changes in species composition, biomass and number of trees were forecasted for the next 50 years. Four scenarios, first – warm-dry, second – cutting dead spruce trees, third – cutting all trees andfourth – planting, were compared to the control one. The analysis revealed a rapid decrease of stand biomass in the first decade as a result of spruce decline. The model predicts an increase in beech biomass before the 50th year of simulation in all scenarios. In the planting scenario, the biomass of beech increased up to 199.9 ± 6.9 t·ha-1 in the 50th year. Correlation analysis showed weak autocorrelations of spruce and negative cross-correlations of spruce with the total stand in control and other scenarios. The output of performed simulations is supported with field and literature data. Results of this study can be applied in the long-term planning of the management and conservation activities in this region. The application of FORDRY model was found useful for analysing the potential scenarios of spruce stand transformation in Nadsyansky Regional Landscape Park.
Źródło:
Folia Forestalia Polonica. Series A . Forestry; 2021, 63, 3; 183-194
0071-6677
Pojawia się w:
Folia Forestalia Polonica. Series A . Forestry
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving the procedure of probabilistic load testing design of typical bridges based on structural response similarities
Wzbogacenie procedury probabilistycznego projektowania próbnego obciążenia mostów typowych na podstawie cech wspólnych mechanicznej odpowiedzi konstrukcji
Autorzy:
Owerko, P.
Winkelmann, K.
Powiązania:
https://bibliotekanauki.pl/articles/1849805.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
obciążenie próbne
most
imperfekcja
niepewność
analiza wrażliwości
analiza probabilistyczna
metoda powierzchni odpowiedzi
symulacja Monte Carlo
metoda elementów skończonych
MES
projektowanie eksperymentu
bridge
in-situ test
load testing
imperfection
uncertainty
sensitivity analysis
probability analysis
response surface method
Monte Carlo simulation
finite element model
FEM
experiment design
Opis:
This paper concerns load testing of typical bridge structures performed prior to operation. In-situ tests of a two-span post-tensioned bridge loaded with three vehicles of 38-ton mass each formed the input of this study. On the basis of the results of these measurements an advanced FEM model of the structure was developed for which the sensitivity analysis was performed for chosen uncertainty sources. Three uncorrelated random variables representing material uncertainties, imperfections of positioning and total mass of loading vehicles were indicated. Afterwards, two alternative FE models were created based on a fully parametrised geometry of the bridge, differing by a chosen global parameter – the skew angle of the structure. All three solid models were subjected to probabilistic analyses with the use of second-order Response Surface Method in order to define the features of structural response of the models. It was observed that both the ranges of expected deflections and their corresponding mean values decreased with an increase of the skewness of the bridge models. Meanwhile, the coefficient of variation and relative difference between the mean value and boundary quantiles of the ranges remain insensitive to the changes in the skew angle. Owing to this, a procedure was formulated to simplify the process of load testing design of typical bridges differing by a chosen global parameter. The procedure allows - if certain conditions are fulfilled - to perform probabilistic calculations only once and use the indicated probabilistic parameters in the design of other bridges for which calculations can be performed deterministically.
Pracę otwiera przegląd najnowszej literatury fachowej o zasięgu międzynarodowym, dotyczącej próbnych obciążeń obiektów mostowych. W licznych publikacjach badawczych jednoznacznie stwierdzono, iż zasadne jest, by często stosowane w tym zakresie metody deterministyczne uzupełniać lub zastępować analizami probabilistycznymi. Niniejsza praca stanowi zatem rozwinięcie dotychczasowych osiągnięć i spostrzeżeń. Przedmiotem pracy jest analiza możliwości zwiększenia efektywności procesu przygotowania probabilistycznych projektów próbnych obciążeń typowych konstrukcji mostowych, różniących się wybranym parametrem geometrycznym (w tym przypadku – kątem ukosu konstrukcji „α”) przed ich dopuszczeniem do eksploatacji w zakresie pomiarów statycznych. Punktem wyjściowym przedstawionej analizy jest próbne obciążenie in-situ typowego, drogowego mostu sprężonego. Jednym z podstawowych kryteriów dopuszczenia obiektu mostowego do użytkowania w niektórych krajach, jest wykazanie, iż ugięcia dźwigarów głównych obiektu mostowego wywołane statycznym obciążeniem próbnym są mniejsze niż te określone teoretycznie w modelu MES obiektu. W pierwszej kolejności zatem, wyniki pochodzące z rzeczywistych badań próbnego obciążenia zostały zestawione z ich teoretycznymi odpowiednikami, pochodzącymi z prostego modelu rusztowego mostu. Ten przykład ogranicza się do analizy maksymalnych ugięć jednego z dźwigarów głównych obiektu. Wykazano, iż ugięcia z pomiarów in-situ (pomierzone przemieszczenia zostały odpowiednio przeliczone na ugięcia, aby uwzględnić wpływ osiadania podpór i zgniotów łożysk) były mniejsze niż te określone teoretycznie. Nie było zatem podstaw do niedopuszczenia mostu do użytkowania ze względu na niespełnienie kryterium ugięć. Jednakże, w rezultacie analizy wykazano, iż wyniki odpowiedzi konstrukcji z prostego modelu deterministycznego różniły się znacznie od wyników pomiarów. W związku z tym, w celu opracowania procedury zwiększenia efektywności procesu przygotowywania probabilistycznych projektów próbnych obciążeń obiektów typowych, do dalszych analiz porównawczych i probabilistycznych wygenerowany został znacząco bardziej zaawansowany model bryłowy MES.
Źródło:
Archives of Civil Engineering; 2020, 66, 4; 325-342
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Integrated Approaches to Determination of CO2 Concentration and Air Rate Exchange in Educational Institution
Autorzy:
Deshko, Valerii
Bilous, Inna
Vynogradov-Saltykov, Volodimer
Shovkaliuk, Maryna
Hetmanchuk, Hanna
Powiązania:
https://bibliotekanauki.pl/articles/1811612.pdf
Data publikacji:
2020
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
educational institution
air quality
СО2 concentration
air exchange
simulation modeling
field experiment
comfort conditions
Opis:
Many old public buildings in Central and Eastern Europe are characterized by low energy efficiency and often lack of mechanical ventilation. The general trends are aimed to improve the energy efficiency of the building sector and to provide comfort conditions. The indoor air quality can be determined based on the CO2 concentrations. In the article, a complex approach to the definition and analysis of data on the indoor CO2 concentration and the air exchange rate in educational institutions at natural air exchange and in the absence of mechanical air circulation was implemented. Educational institutions in Kyiv have been considered. The study of the CO2 concentration of indoor and outdoor air of three typical schools of mass development in the 80 s, as well as the training building of Igor Sikorsky KPI, was carried out. Experimental determination of the background CO2 concentration during the day next to the considered objects showed that the background concentration of CO2 is in the range of 400-420 ppm. Measurements of the CO2 concentration distribution were carried out after classes throughout the classroom area, according to which the difference between the values at the level of the working area was 30...180 ppm. It was found that the concentration of CO2 varies during classes between 700-1100 ppm. During the break, the CO2 concentration decreases to 500-1000 ppm, depending on the type of ventilation. Experimental data on the dynamics of changes in the indoor CO2 concentration are used to determine the air exchange rate based on balances of air flows and CO2. It is shown that the number of present persons influences the indoor CO2 concentration more significantly than the air exchange rate. On the example of an experimental study of the CO2 concentration in the classrooms for high school students it was found that the air exchange rate during the classes is in the range of 0.4...0.75 h-1. During breaks the air exchange rate increases to 2.9-3.5 h-1. For the range considered, the weighted average air exchange rate is 0.8 h-1, and even with forced airing, the air exchange rate is insufficient to ensure acceptable CO2 concentration. For the training building of Igor Sikorsky KPI a field experiment was carried out to determine the dynamics of changes in CO2 concentration in time and on the basis of it the air exchange rates for representative classrooms were determined. The concentration of CO2 ranged from 500 to 2000 ppm and increases by 350-850 ppm depending on the use and location of classrooms. Based on experimental data, the air exchange rate for the training building of the education institution is in the range of 0.35-0.7 h-1. During the periods of airing the air exchange may increase by 0.45 h-1, but this does not allow reaching the standard value. When analyzing the obtained results, simulation models of natural air exchange of the examined classrooms were used on the basis of the improved ASHRAE method. The natural air exchange rate based on simulations is in the -0.8…0.5 h-1 range. Negative values are explained by exfiltration, which is typical for the upper floors. Not only the comfort and condition of the building envelope, but also the total energy consumption of the building depend on the actual level of air exchange rate. In the total energy balance the ventilation component is 30-60%. Further use of the obtained results can be connected with monitoring of the actual level of air exchange rate and its consideration during complex modernization or implementation of the ventilation systems with heat recovery in the premises of educational institutions.
Źródło:
Rocznik Ochrona Środowiska; 2020, Tom 22, cz. 1; 82-104
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation and experimental study of hydraulic cylinder in oscillating float-type wave energy converter
Autorzy:
Lai, Wenbin
Li, Detang
Xie, Yonghe
Powiązania:
https://bibliotekanauki.pl/articles/259898.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
wave energy converter
hydraulic cylinder
AMESim simulation
model experiment
Opis:
Hydraulic cylinders play a vital role in the energy output (PTO) system of an oscillating float-type wave Energy converter, whose function is to convert the mechanical energy captured by the float from the waves into hydraulic energy. The performance of the hydraulic cylinder determines the conversion efficiency of mechanical energy to hydraulic energy in the system; therefore, it is necessary to study the working mechanism of the hydraulic cylinder. This paper takes a self-developed oscillating float-type wave energy converter as the research object, and studies the working mechanism of its hydraulic cylinder, and uses the linear analysis method to derive the critical self-excited vibration curve of the hydraulic cylinder. In addition, the effects of the external load, hydraulic cylinder load mass, stroke length, spring stiffness and piston area on the performance of the hydraulic cylinder were studied by AMESim simulation software. According to the simulation results, a physical model of the hydraulic cylinder is established. Finally, the physical model is tested in a hydrodynamic pool. The test results show that the hydraulic cylinder can stably and efficiently convert mechanical energy into hydraulic energy even under small waves, thus verifying the rationality of the hydraulic cylinder design.
Źródło:
Polish Maritime Research; 2020, 2; 30-38
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A statistical approach to simulate instances of archeological findings fragments
Autorzy:
Renno, Fabrizio
Lanzotti, Antonio
Papa, Stefano
Powiązania:
https://bibliotekanauki.pl/articles/384409.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
archetype
profile reconstruction
geometric modeling
design of experiment
simulation of the shape
simulation of recognition error
archetyp
modelowanie geometryczne
projekt eksperymentu
symulacja kształtu
Opis:
First aim of this paper is to describe a methodology developed to create virtual fragments of archeological archetypes in CAD (Computer Aided Design) environment. A simple Reverse Engineering (RE) technique was adopted to reconstruct the shape of vases allowing the archeologists, and so the CAD inexpert personnel, to use it. Moreover, another relevant aspect is the definition of a procedure to simulate shape errors on the virtual prototypes to make more realistic the results. The characteristics of the fragments to be reproduced were selected by means of Design of Experiment (DOE) techniques. So, an algorithm was implemented to simulate the shape error, related to the working operations, that represents the typical noise for the feature recognition of archeological findings. Furthermore, this algorithm can make more complex the hypotheses related to the Gaussian model of simulation of the error and can adapt the value of the shape error (i.e. increasing it) according to the data gathered in archaeological excavation. The case study was based on the definition of a catalogue of archetypes of the black Campanian vases studied and classified by the archeologist J.P. Morel. The procedure conceived was applied to five (among one hundred) vases of the virtual catalogue obtaining forty instances of fragments affected by errors and so creating virtual mock-ups of typical pieces which may be found in the archeological site considered for the case study.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2019, 13, 1; 46-64
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the road linear optimization design of bridge and tunnel connecting segment in the canyon
Autorzy:
Wang, Lu
Liu, Yuwen
Chen, Xiaoxin
Powiązania:
https://bibliotekanauki.pl/articles/223553.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
traffic engineering
curved road
simulation experiment
radius of curve
bridge
tunnel
traffic safety
inżynieria ruchu
łuk drogi
eksperyment symulacyjny
promień łuku
most
tunel
bezpieczeństwo na drodze
Opis:
It is easy to skid and roll by centrifugal force and wind, which affects the safety of the vehicle. At the same time, the special location of bridge and tunnel connecting segment in the canyon will accelerate the wind, and make the transverse wind play a more important role in driving vehicles. Based on the acceleration effect of canyons on wind, the vehicle model is simulated by Carsim software, and the road and wind models are established. It is studied that the vehicle has different radius of circular curve under different wind levels, corresponding to different superelevation. The lateral acceleration, lateral deflection and transverse force coefficient are selected as the running state of the vehicle at different speeds to research the linear optimization design of bridge and tunnel connecting segment in the canyon. The result shows that when the wind force exceeds the fifth grade, it is possible for the vehicle to overturn under the limit minimum radius required by the standard value. In order to ensure the stability and safety of the vehicle, this paper considers the geographical position of bridge and tunnel connecting segment in the canyon and the relationship between the radius of the superelevation and circular curve. What’s more, it puts forward the optimal limit minimum radius of the circular curve with different wind grades of 5-9 grades. At the same time, when the road alignment cannot be optimized under the condition, this paper puts forward the speed limit that the vehicle safety can be guaranteed under different wind speed conditions. The speed limit can provide reference for traffic management and safety guarantee of mountain expressway.
Źródło:
Archives of Transport; 2019, 52, 4; 81-93
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of outsourcing transportation contract using simulation and design of experiment
Ocena kontraktów outsourcingowych w transporcie z wykorzystaniem symulacji i projektu eksperymentu
Autorzy:
Setamanit, S.
Powiązania:
https://bibliotekanauki.pl/articles/405939.pdf
Data publikacji:
2018
Wydawca:
Politechnika Częstochowska
Tematy:
design of experiment
optimal fleet size
outsourcing
simulation modelling
transportation contract
transportation management
variation
projekt eksperymentu
optymalny rozmiar floty
modelowanie symulacyjne
umowa transportowa
zarządzanie transportem
zmiana
Opis:
This paper aims to develop an approach to identify optimal fleet size under uncertainty and to identify important factors affecting transportation performance. The methodologies used in this paper are two folded. The first methodology is to develop a simulation model that allows manager to evaluate the impact of having different number of trailers on delivery and cost in order to identify the optimal fleet size. The second methodology is to use a Design of experiment (DOE) together with the simulation model to identify important factors that affect transportation performances. The result shows that the company should hire 16 trailers, which will reduce the delivery delay from 14% to 0.02%. Furthermore, it is found that variation in demand has a strong impact on late delivery and cost. There is also an interaction between demand variation and transportation time variation.
Niniejszy dokument ma na celu opracowanie podejścia do określania optymalnej wielkości floty w warunkach niepewności oraz określenie ważnych czynników wpływających na wydajność transportu. Metodologie stosowane w tym artykule są złożone. Pierwszą metodologią jest opracowanie modelu symulacyjnego, który umożliwi menedżerowi ocenę wpływu posiadania różnych przyczep i kosztów w celu określenia optymalnego rozmiaru floty. Drugą metodologią jest wykorzystanie projektu eksperymentu (DOE) wraz z modelem symulacyjnym w celu zidentyfikowania ważnych czynników wpływających na wydajność transportu. Wynik pokazuje, że firma powinna wynająć 16 przyczep, co zmniejszy opóźnienie dostawy z 14% do 0.02%. Ponadto stwierdzono, że zróżnicowanie popytu ma duży wpływ na opóźnienia w dostawie i koszty. Istnieje również interakcja między zmiennością popytu a zmiennością czasu transportu.
Źródło:
Polish Journal of Management Studies; 2018, 18, 2; 300-310
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-objective optimization of stope structure parameters in broken rock conditions using grey relational analysis
Wielo-kryterialna optymalizacja parametrów struktury przodka wybierkowego w warunkach pękania skał przy wykorzystaniu „szarej” analizy relacyjnej
Autorzy:
Chen, S.
Wu, A.
Wang, Y.
Cheng, X.
Powiązania:
https://bibliotekanauki.pl/articles/219180.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
szara analiza relacyjna
parametry struktury przodka wybierkowego
pękanie skał
symulacje numeryczne
model Taguchi projektowania eksperymentu
grey relational analysis
stope structure parameters
in broken rock conditions
numerical simulation
taguchi experiment design
Opis:
In order to optimize the stope structure parameters in broken rock conditions, a novel method for the optimization of stope structure parameters is described. The method is based on the field investigation, laboratory tests and numerical simulation. The grey relational analysis (GRA) is applied to the optimization of the stope structure parameters in broken rock conditions with multiple performance characteristics. The influencing factors include stope height, pillar diameter, pillar spacing and pillar array pitch, the performance characteristics include maximum tensile strength, maximum compressive strength and ore recovery rate. The setting of influencing factors is accomplished using the four factors four levels Taguchi experiment design method, and 16 experiments are done by numerical simulation. Analysis of the grey relational grade indicates the first effect value of 0.219 is the pillar array pitch. In addition, the optimal stope structure parameters are as follows: the height of the stope is 3.5 m, the pillar diameter is 3.5 m, the pillar spacing is 3 m and the pillar array pitch is 5 m. In-situ measurement shows that all of the pillars can basically remain stable, ore recovery rate can be ensured to be more than 82%. This study indicates that the GRA method can efficiently applied to the optimization of stope structure parameters.
W pracy zaproponowano nową metodę optymalizacji parametrów struktury przodka wybierkowego prowadzonego w warunkach pękania skał. Metoda opiera się na badaniach terenowych, wykorzystuje także badania laboratoryjne oraz symulacje numeryczne. Do optymalizacji parametrów struktury przodka wybierkowego prowadzonego w warunkach pękania skał dla wielu wariantów charakterystyki górotworu wykorzystano ‘szarą’ analizę relacyjną (GRA – Grey Relational Analysis). Uwzględnione czynniki wpływu to wysokość przodka, średnica filarów, rozstaw filarów, rozmieszczenie filarów oraz charakterystyki górotworu: maksymalna wytrzymałość na rozciąganie oraz ściskanie oraz uzysk rudy. Ustawienia czynników wpływu dokonano z wykorzystaniem czterech czynników i dla czterech poziomów wg metody Taguchi planowania eksperymentów; ponadto 16 eksperymentów wykonano z wykorzystaniem symulacji numerycznych. Wyniki ‘szarej’ analiza relacyjnej wskazują, że wartość efektywna dla pierwszego z czynników, czyli rozmieszczenia filarów, wyniosła 0.219. Ponadto, otrzymano następujące optymalne parametry przodka: wysokość przodka 3.5 m; średnica filarów 3.5 m, rozstęp pomiędzy filarami 3 m, rozciągłość filarów 5 m. Pomiary przeprowadzone in situ wykazały, że wszystkie filary zasadniczo powinny zachować stabilność, a uzysk rudy przekroczyć może 82%. Wyniki wskazują, że ‘szara’ analiza relacyjna może być z powodzeniem wykorzystywana do optymalizacji parametrów struktury przodka wybierkowego.
Źródło:
Archives of Mining Sciences; 2018, 63, 2; 269-282
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Simulation Experiment and Multi-Criteria Assessment of Manufacturing Process Flow Variants Tested on a Computer Model
Autorzy:
Kukla, S.
Smetana, M.
Powiązania:
https://bibliotekanauki.pl/articles/117956.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
computer model
simulation experiment
multicriteria assessment
Opis:
The article presents issues relating to designing and improvement of manufacturing processes based on a modelling and simulation method. The 3D model of a production line has been designed and simulation experiment, conducted on the Arena model prepared in a versatile package for modelling and simulation of manufacturing systems and representing functioning of the system, has been carried out. The results obtained from the experiment and analyses of time and ergonomics of work at a work station were subject to multi-criteria assessment based on a point-by-point method of assessment according to Yager.
Źródło:
Applied Computer Science; 2017, 13, 2; 72-81
1895-3735
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling characteristics of spark ignition engine injection system
Autorzy:
Dziubiński, M.
Litak, G.
Drozd, A.
Żukowicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/101878.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
modelling
simulation
diagnostics
injection system
experiment
Opis:
The carried out modelling of SI engine injection system characteristics in various steady-state conditions has been presented in the article. Also, the two ways of determining injection time have been shown: by means of a virtual model made with the use of software worked out by National Instruments LabVIEW and on the experimental test stand ‘’Integrated injection-ignition system of the K16 engine”.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 2; 103-117
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Material Model of the Polyurethane Elastomer on the FEM Calculations Quality for the Various Modes of Loading
Autorzy:
Kut, S.
Ryzińska, G.
Niedziałek, B.
Powiązania:
https://bibliotekanauki.pl/articles/352180.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
elastomers
material tests
material models
FEM simulation
experiment
Opis:
The paper presents research to verify the effectiveness of nine selected material models of elastomeric materials based on uniaxial tension test. Basing on the cyclic uniaxial tension test of elastomers sample, the stress-strain characteristic for the 18th load cycle was prepared. On the basis of the obtained characteristic, the values of material constants were calculated for the studied models (Neo-Hookean, Mooney with two and three constants, Signorini, Yeoh, Ogden, Arruda-Boyce, Gent and Marlow) and simulation of tensile, upsetting and bending processes was performed with the usage of the software MARC/Mentat. The effectiveness of the selected models was determined based on a comparison of results obtained in the experimental tensile test, upsetting test and bending test of an elastomeric samples with the results of numerical FEM calculations for each models. The research has shown that, for modeling of the elastomeric cylinder upsetting in the range of deformation of 62%, the best results with the comparison of the experiment were obtained by using the Yeoh model. In the bending process none of the analyzed models indicate a high convergence of results from an experiment. Analyzing the characteristics of the experimental and numerical tensile test it can be seen that in the entire range of punch movement (0 to 55 mm), models Signorini, Marlow, Ogden(N3) and Mooney(3) give the best results.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 523-530
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical and experimental investigation of methane-oxygen detonation in a 9 m long tube
Autorzy:
Malik, K.
Żbikowski, M.
Teodorczyk, A.
Lesiak, P.
Powiązania:
https://bibliotekanauki.pl/articles/246813.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
detonation
methane
combustion
simulation
experiment
characteristic cell size
Opis:
Numerical investigation of methane-oxygen detonation parameters was conducted with an OpenFoam code. Custom solver ddtFoam made especially for detonation problems was made use of. It uses the HLLC scheme to resolve the discontinuities and the subgridscale model to improve results on coarse meshes. Combustion model is based on progress variable equation, which contains two source terms. The first is the deflagrative source term and is modelled using the Weller correlation. The second is the detonative source term and it accounts for autoignition effects. Range of analysed gaseous mixture compositions was 20, 33 and 40% of methane in oxygen. The 2D calculation geometry was a 9 m long pipe with diameter 0.17 m. The mesh consisted of 382 500 hexahedral cells with the dimensions of 2x2 mm. Experimental results such as pressure profiles and detonation velocities are presented. Simulations were performed using LES turbulence model (k-equation-eddy-viscosity model) and compared with experimental data. Various dynamic parameters, like for example reaction lengths for methane-oxygen detonations, are estimated from the steady ZND analyses conducted in Cantera and SDToolbox libraries and based on GRI 3.0 kinetic mechanism of methane combustion. These lengths were then used in empirical formulas to obtain the characteristic cell sizes and assessed against experimental data.
Źródło:
Journal of KONES; 2016, 23, 4; 311-318
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 42

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