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Tytuł:
Effects of sway and roll excitations on sloshing loads in a KC-1 membrane LNG tank
Autorzy:
An, Se-yeol
Jeong, Hyeon-won
Kim, Ohyoung
Shim, W. Jaewoo
Powiązania:
https://bibliotekanauki.pl/articles/34600997.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
KC-1 membrane LNG tank
sloshing
sway
roll
coupled sway-roll
Fast Fourier transform (FFT)
Opis:
This study investigates the effects of sway and roll excitations on sloshing liquid loads in a tank, using Ansys Fluent software. The model considered in the study is a 1:50 scaled membrane-type tank, based on a KC-1 membrane LNG tank designed by Korea Gas Corporation (KOGAS). The volume of fluid (VOF) method is used to track the free surface inside the tank, and the standard k-ε model is applied to express the turbulent flow of the liquid. To explore the motion of the tank under excitation, a user-defined function (UDF) and a dynamic mesh technique are employed to control the external forces exerted on the tank through its motion. The results, in the form of time series data on the sloshing pressures in the tank under pure sway, roll, and coupled sway-roll, are analysed, with specific ranges for the excitation amplitudes and frequencies. We show that variations in excitation frequency and amplitude significantly influence the sloshing loads. Sloshing loads are found to intensify when the excitation frequency matches the tank’s primary natural frequency, 1.0 ω'1. Furthermore, with coupled sway-roll excitations, the sloshing loads are weakened when the sway and roll are in-phase and are intensified when these are out-of-phase. Fast Fourier transform analysis provides insights into the frequency domain, showing that the dominant frequency is 0.88 Hz and it is approximately equal to the tank’s primary natural frequency, 1.0 ω'1.
Źródło:
Polish Maritime Research; 2023, 4; 43-53
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Genetic fuzzy approach to adaptive crane control system
Autorzy:
Smoczek, J.
Powiązania:
https://bibliotekanauki.pl/articles/243018.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
anti-sway crane control
pole placement
fuzzy logic
genetic algorithm
Opis:
In automated manufacturing processes the safety, precise and fast transfer of goods realized by automated material handling devices is required to raise efficiency and productivity of manufacturing process. Hence, in those industrial branches where cranes are extensively used the problem of an anti-sway crane control is especially important to speed-up the time of transportation operations and ensures the safe and effective transportation operations. The precise positioning of a cargo requires controlling the speed of crane motion mechanisms to reduce the sway of a payload. Moreover, the anti-sway crane control scheme involves applying the adaptive techniques owing to the nonlinearities of a system that comes especially from stochastic variation of rope length on which a payload is suspended and mass of this payload. The paper provides the design method of an adaptive control system for a planar model of crane. The control system is based on the gain scheduling control scheme created using fuzzy logic controller with Takagi-Sugeno-Kang-type fuzzy implications. The design process of a gain scheduling control system consists in selecting such a suitable set of operating points at which the linear controllers are determined that interpolation control scheme ensures the expected control quality within the known range of nonlinear system parameters changes, when those parameters vary in relation to the exogenous variables: rope length and mass of a payload. The method that is proposed in this paper to solve the problem of designing the fuzzy gain scheduling crane control system for minimum set of operating points is based on the pole placement method and genetic algorithm.
Źródło:
Journal of KONES; 2012, 19, 4; 577-584
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design templates-a new tool for computer-aided design of structural elements
Autorzy:
Murzewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/279757.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
computer-aided design
load combination
load effect interaction
steel frames
sway amplification
Opis:
A design template is define as a scheme of computer-aided design process which could be verified and modified in particular cases by a designer. Global loads have to be determined and analysis is performed for each arrangement of unit loads separately. Thus, the influence matrices are determined and also; matrix of interaction of load effects and matrix of combination of simultaneous loads. New matrix procedures are itroduced in order to identify the most unfavourable load effect interactions. the design templates are exemplified for portal steel frames subject to permanent loads, variable actions and second-order horizontal forces due to sway of the columns. Complex influence coefficients are introduced and amplified sway of the frame is taken into consideration. Corrections of some unsound clauses of the Eurocodes 1 and 3 are suggested.
Szablony projektowania - nowe narzedzie komputerowych obliczeń elementów konstrukcji Szablon projektowania definiuje się jako wcześniej przygotowany układ obliczeń komputerowych, który może być sprawdzany i modyfikowany w poszczególnych przypadkach przez projektanta, co nie jest możliwe przy korzystaniu z komputerowych programów projektowania. Ustalić trzeba najpierw obciążenia globalne i wykonać obliczenia statyczne dla każdego wariantu obciążeń jednostkowych z osobna. W wyniku obliczeń statycznych formułuje się macierze blokowe wpływu obciążeń. Okresla się następnie macierze współdziałania sił wewnętrznych i macierze kombinacji jednoczesnych obciążeń. Stosuje się nowe procedury macierzowe w celu wyszukania najbardziej niekorzystnych wariantów dla każdego niezależnego obciążenia z osobna, a następnie - najbardziej niekorzystnego przypadku współdziałania sił wewnętrznych i kombinacji obciążeń. Przykładowy szablon projektowania dotyczy stalowej ramy portalowej pod obciążeniem stałym z działaniami zmiennymi oraz siłami drugiego rzędu wynikającymi z przechyłu słupów. Na początku obliczeń iteracyjnych określa się zespolone współczyniki wpływu obciążeń i wstawia próbną wartość dopełnionego kąta przechyłu. Proponuje się przy tym poprawki pewnych nieścisłych wzorów Eurokodu 1 i 3.
Źródło:
Journal of Theoretical and Applied Mechanics; 2000, 38, 2; 331-350
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of short- and long-term vibration training on postural stability in men
Autorzy:
Piecha, M.
Król, P.
Juras, G.
Sobota, G.
Polak, A.
Bacik, B.
Powiązania:
https://bibliotekanauki.pl/articles/306693.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mechanical oscillations
postural sway
whole body vibration
trening wibracyjny
postawa człowieka
Opis:
The study aimed to establish the short- and long-term effects of vibration on postural stability in young men. A single set of exercises and a 4-week vibration training were assessed for their impact on the center of foot pressure (COP) sway. The sample consisted of 49 male subjects randomly allocated to seven comparative groups, six of which exercised on a vibration platform whose parameters were set individually for the groups. Group VII was the control group. The stabilographic signal was recorded before the test commenced, after a single application of vibration, before the last set of exercises of the 4-week vibration training, immediately afterwards, as well as one week and one month after the training ended. The subjects were exposed to vibration 3 times a week for 4 weeks. Both a single application of vibration and the 4-week vibration training had an effect on all parameter values, but most changes were statistically insignificant. Group III was the only one where the COP sway in the anterior-posterior direction significantly increased after a single exposure to vibration and significantly decreased in both anterior-posterior and medio-lateral planes one week after vibration training compared with the pre-test recordings.
Źródło:
Acta of Bioengineering and Biomechanics; 2013, 15, 3; 29-35
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected measurement and control techniques : experimental verification on a lab-scaled overhead crane
Autorzy:
Szpytko, J.
Hyla, P.
Kosoń-Schab, A.
Smoczek, J.
Powiązania:
https://bibliotekanauki.pl/articles/950147.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
overhead crane
modelling
vision systems
anti-sway control
Metal Magnetic Memory
Opis:
This article presents three independent concepts of use high-level technique with it adaptation and implementation concerning overhead travelling crane device type. The main objective of this statement applies a solution for device workspace mapping, payload anti-sway control techniques strategy use and possibility of reliable steel construction health monitoring. In the first chapter, the vision system technology for obstacle in workspace visualization was presented. The main idea depends on use stereovision system with sets of camera mounted under the crane’s trolley which movement with the crane shifts. The stereo pictures, after digital processing, were used for develop so-called dense disparity map. The described architecture allows achieving information about device surroundings and obstacle position in the workspace. As the final result was presented three-dimensional map of the device workspace with obtained result accuracy discussion. The second type of described problem developed in chapter two concern the crane control methodology of designing the anti-sway system for payload stabilizing during the crane movement. The oscillation of a payload adversely affects the accuracy of performed transportation tasks and may present a safety hazard to employees, transferred payload and surrounding objects. The invented and described method mainly base on so-called soft computing methods. The next part of the article-focused attention of problem concerning health monitoring cranes construction as other equipment’s as well. The problem concerns usually the large industrial cranes carry out transportation operations in the presence of a large impact load and mechanical stresses acting overall crane’s structure. The safety and efficiency of crane operations can be improved through providing the continuous structural health monitoring as well in on-line and off-line mode. The main idea allows using Metal Magnetic Memory technique for supervising and estimating steel construction actual condition. All tests and considerations were conducted on the scaled physical model of overhead travelling crane with hosting capability 150 kg
Źródło:
Journal of KONES; 2017, 24, 3; 299-308
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possibility of use a smart camera as a non-contact sway sensor in insufficient light condition – case study
Autorzy:
Hyla, P.
Szpytko, J.
Powiązania:
https://bibliotekanauki.pl/articles/393679.pdf
Data publikacji:
2015
Wydawca:
Polskie Stowarzyszenie Telematyki Transportu
Tematy:
sway sensor
image analysis
night vision
smart camera
analiza obrazów
inteligentna kamera
noktowizja
Opis:
Contemporary handling operation efficiency and safety in cargo transportation realized by the cranes mainly depends on counteractions taken against undesirable phenomena’s such as payload swing. The research problem connected with anti-sway problem has been extensively researched over the past decades. Generally the proposed solutions can be classifying as an open and closed-loop control system. The close loop sway angle control system are strongly connected with necessity of physical measuring the angle of the swinging rope. The paper was focused on the non-contact method of measuring the angle of swinging payload with the image analysis technique use. However, in the statement the authors attention was focused on the issue related to the verification that infrared light illuminator can be used in built a non-contact vision sensor for the sway measure insensitiveness on actual exposure light conditions. All experiments and tests were conducted on the scaled physical model of overhead travelling crane with hosting capability of 150 kg.
Źródło:
Archives of Transport System Telematics; 2015, 8, 1; 8-13
1899-8208
Pojawia się w:
Archives of Transport System Telematics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interval arithmetic-based fuzzy discrete-time crane control scheme design
Autorzy:
Smoczek, J.
Powiązania:
https://bibliotekanauki.pl/articles/201270.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
interval arithmetic
discrete-time control
fuzzy control
pole placement
anti-sway control
Opis:
In many manufacturing segments, container terminals and shipping yards the automation of material handling systems is an important element of enhancing productivity, safety and efficiency. The fast, precise and safe transfer of goods in crane operations requires a control application solving the problems, including non-collision trajectory planning and limitation of payload oscillations. The paper presents the interval arithmetic-based method of designing a discrete-time closed-loop anti-sway crane control system based on the fuzzy interpolation of linear controller parameters. The interval analysis of a closed-loop control system characteristic polynomial coefficients deviation from their nominal values is proposed to define a minimum number of fuzzy sets on the scheduling variables universe of discourse and to determine the distribution of triangular-shaped membership functions parameters, which satisfy the acceptable range of performances deterioration in the presence of the system’s parameters variation. The effectiveness of this method was proved in experiments conducted using the PAC system on the laboratory scaled overhead crane.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2013, 61, 4; 863-870
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combination of feedback control and spring-damper to reduce the vibration of crane payload
Autorzy:
Nguyen, Trong Kien
Powiązania:
https://bibliotekanauki.pl/articles/1845035.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Coriolis force
anti-sway control
feedback control
siła Coriolisa
kontrola zapobiegająca kołysaniu
kontrola sprzężenia zwrotnego
Opis:
Operating cranes is challenging because payloads can experience large and dangerous oscillations. Anti-sway control of crane payload can be approached by the active methods, such as feedback control, or passive methods. The feedback control uses the feedback measurement of swing vibration to produce the command sent to a motor. The feedback control shows good effectiveness, but conflict with the actions of the human operator is a challenge of this method. The passive method uses the spring-damper to dissipate energy. The passive method does not cause conflict with the human operator but has limited performance. This paper presents the combination of two methods to overcome the disadvantages of each separate one. The passive method is used to improve the efficiency of the feedback method to avoid conflicts with the human operator. The effectiveness of the combination is simulated in a 2D crane model.
Źródło:
Archive of Mechanical Engineering; 2021, LXVIII, 2; 165-181
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acute effects of core stability exercises on balance control
Autorzy:
Szafraniec, R.
Barańska, J.
Kuczyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/307089.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
stabilność postawy
posturografia
mięśnie tułowia
postural stability
motor learning
posturography
balance training
trunk muscles
sway entropy
Opis:
The aim of this study was to investigate whether a single bout of core stability exercises improves body balance immediately after the bout of exercise and during a retention test. Methods: The study involved 16 women (age 22–25 years, body weight 60.5 ± 5.2 kg, height 166 ± 5.4 cm). Postural stability was assessed in the mediolateral (ML) and anteroposterior (AP) planes separately on a force plate (Kistler 9286 AA) during quiet standing on a soft support surface with the eyes closed. Subjects were measured 4 times: just before (T0), 1 minutes after (T1 m), 30 minutes after (T30 m), and 24 hours after the workout (T24 h). Postural balance was evaluated by five parameters based on the center of pressure (COP) signal: variability (VAR), mean velocity (VEL), sample entropy (ENT), frequency (FRE), and fractal dimension (FRA). Results: We observed a decrease in VAR and VEL in the ML plane at T30 m and T24 h, compared to T0. The COP entropy significantly increased in the ML plane at T24 h, compared to T0. Conclusions: A single bout of core stability exercises improved the control of the mediolateral body balance. This effect was evident within 30 minutes after exercise, and remained for at least 24 hours. In addition, 24 hours after exercise we observed an increased automaticity in the strategy to maintain a stable upright stance.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 3; 145-151
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statyczne i dynamiczne testy równowagi u osób trenujących Taekwondo
Static and dynamic test of postural control in Taekwondo contenders
Autorzy:
Podbielska, M.
Senhadri, H.
Kuczyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/261190.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Wydział Podstawowych Problemów Techniki. Katedra Inżynierii Biomedycznej
Tematy:
sporty walki
wychwiania
równowaga
siła reakcji podłoża
combat sports
sway
body balance
ground reaction force
Opis:
Równowaga dynamiczna i statyczna oceniania była u osób w wieku 19 do 27 lat, trenujących Taekwondo i w grupie kontrolnej, nieuprawiającej aktywności fizycznej. Równowaga statyczna była mierzona w czasie 20 s spokojnego stania na platformie stabilograficznej. Równowaga dynamiczna oceniana była przez 2,5 s po skoku na platformę i zeskoku z platformy. Nie stwierdzono znaczących różnic w równowadze statycznej pomiędzy grupami. W grupie osób uprawiających Taekwondo zmierzono mniejsze zmiany sił reakcji podłoża po skoku jednonożnym na platformę niż u osób nieuprawiających sportu, co dowodzi lepszej równowagi dynamicznej.
Static and dynamic postural stability was tested on a force plate between recreational Taekwondo athletes (TAE) and subjects who were not involved in any systematic sports activities (CON) aged 18 to 27 years. The static stability was measured in single- and double-leg 20 s quiet stance. The dynamic stability was assessed by the standard deviation of the ground vertical forces during 2.5 s period after landing in two tests: hopping and leaping on the force plate. The results revealed similar postural sway in TAE and in CON groups during a 20-sec quiet stance indicating that the traditional interpretation of stabilographic findings may be sometimes misleading in the assessment of postural performance in athletes. However, the vertical force variability that resulted from a single-leg hopping on the force plate was much lower in athletes than in controls.
Źródło:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna; 2013, 19, 2; 79-84
1234-5563
Pojawia się w:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-10 z 16

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