scholarly journals Dynamic Analysis of Semi-Flexible Multibody Systems: Coordinates Relatives Method

2008 ◽  
Author(s):  
Alexis Mouhingou ◽  
Naoufel Azouz
Keyword(s):  
Dynamic Model ◽  
Multibody Systems ◽  
Dynamic Behaviour ◽  
Central Body ◽  
Dynamic Modelling ◽  
Complete Model ◽  
Aerodynamic Loads ◽  
Rigid Model ◽  
Flexible Arms ◽  
Control Study

This work presents the dynamic modelling of a multibody systems in cross form constituted of a central body which is connected four flexible arms, at each end of arm is connected a rotor. A particular attention is given to the influence of flexibility on the dynamic behaviour of system. For elaborate the complete dynamic model, one consider the sub-structuration technique in using the Lagrangian approach based on the relatives coordinates method of central body. One establishes then the mathematics equations permitting to obtain the dynamic model of motion for the simulation and the control study. The aerodynamic loads and the gravity force are taking into account for the dynamic complete model. At the end, one considers the case of stationary flight of a miniature Quadrotor. The numerical results permit to simulate the motion of Quadrirotor in flight. But also to compare the flexible and rigid model in order to resort the flexibility effects.

scholarly journals Dynamic Modelling, Experimental Identification and Computer Simulations of Non-Stationary Vibration in High-Speed Elevators

2021 ◽  
Vol 67 (6) ◽  
Author(s):  
Radomir Đokić ◽  
Jovan Vladić ◽  
Milan Kljajin ◽  
Vesna Jovanović ◽  
Goran Marković ◽  
...  
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Dynamic Behaviour ◽  
Dynamic Modelling ◽  
Control Program ◽  
Specific Method ◽  
Unique Method ◽  
Stationary Vibration ◽  
Vertical Vibrations ◽  
Stiffness And Damping

Modelling the dynamic behaviour of elevators with high lifting velocities (contemporary elevators in building construction and mine elevators) is a complex task and an important step in the design process and creating conditions for safe and reliable exploitation of these machines. Due to high heights and lifting velocities, the standard procedures for dynamic exploitation are not adequate. The study presents the method of forming a dynamic model to analyse nonstationary vibrations of a rope with time-varying length with nonholonomic boundary conditions in the position where the rope is connected with the cabin (cage) and in the upcoming point of its winding onto the pulley (drum). A unique method was applied to identify the basic parameters of the dynamic model (stiffness and damping) based on experimental measures for a concrete elevator. Due to the verification of this procedure, the experiment was conducted on a mine elevator in RTB Bor, Serbia. Using the obtained computer-experimental results, the simulations of the dynamic behaviour of an empty and loaded cage were shown. In addition, the study shows the specific method as the basis for forming a control program that would enable the decrease in vertical vibrations during an elevator starting and braking mode.

Fully Coupled Three-Dimensional Dynamic Response of a TLP Floating Wind Turbine in Waves and Wind

2012 ◽  
Author(s):  
G. K. V. Ramachandran ◽  
H. Bredmose ◽  
J. N. Sørensen ◽  
J. J. Jensen
Keyword(s):  
Wind Turbine ◽  
Dynamic Model ◽  
Three Dimensional ◽  
Geographic Location ◽  
Climatic Conditions ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Total System ◽  
Wave Loads ◽  
Aerodynamic Loads

A dynamic model for a tension-leg platform (TLP) floating offshore wind turbine is proposed. The model includes three-dimensional wind and wave loads and the associated structural response. The total system is formulated using 17 degrees of freedom (DOF), 6 for the platform motions and 11 for the wind turbine. Three-dimensional hydrodynamic loads have been formulated using a frequency- and direction-dependent spectrum. While wave loads are computed from the wave kinematics using Morison’s equation, aerodynamic loads are modelled by means of unsteady Blade-Element-Momentum (BEM) theory, including Glauert correction for high values of axial induction factor, dynamic stall, dynamic wake and dynamic yaw. The aerodynamic model takes into account the wind shear and turbulence effects. For a representative geographic location, platform responses are obtained for a set of wind and wave climatic conditions. The platform responses show an influence from the aerodynamic loads, most clearly through a quasi-steady mean surge and pitch response associated with the mean wind. Further, the aerodynamic loads show an influence from the platform motion through more fluctuating rotor loads, which is a consequence of the wave-induced rotor dynamics. In the absence of a controller scheme for the wind turbine, the rotor torque fluctuates considerably, which induces a growing roll response especially when the wind turbine is operated nearly at the rated wind speed. This can be eliminated either by appropriately adjusting the controller so as to regulate the torque or by optimizing the floater or tendon dimensions, thereby limiting the roll motion. Loads and coupled responses are predicted for a set of load cases with different wave headings. Based on the results, critical load cases are identified and discussed. As a next step (which is not presented here), the dynamic model for the substructure is therefore being coupled to an advanced aero-elastic code Flex5, Øye (1996), which has a higher number of DOFs and a controller module.

scholarly journals RANCANG BANGUN KEBIJAKAN PENGEMBANGN BUDIDAYA LELE MELALUI PENDEKATAN MODEL DINAMIK

2016 ◽  
Vol 3 (1) ◽  
pp. 153
Author(s):  
Budi Wardono ◽  
Prayudi Budi Utomo
Keyword(s):  
Dynamic Model ◽  
Dynamic Modelling ◽  
Local Production ◽  
Policy Model ◽  
The Third ◽  
Local Product ◽  
Aquaculture Production ◽  
Potential Land

Lele merupakan salah satu komoditas perikanan ekonomis penting yang mendapat prioritasdalam Program Minapolitan Kementerian Kelautan dan Perikanan, terutama di Kabupaten Gunungkidul.Penelitian ini dilakukan pada tahun 2011 yang berlokasi di Propinsi Daerah Istimewa Yogyakarta.Tujuan penelitian adalah menyusun model kebijakan pengembangan perikanan budidaya Ikan Leleuntukmendukung produksi perikanan budidaya melalui pendekatan model dinamik. Teknik analisisini berasumsi bahwa apabila sistem perikanan dipertahankan, permintaan Ikan Lele akan mengalamikenaikan. Hasil simulasi menunjukkan bahwa permintaan meningkat dan puncaknya terjadi pada tahunke 4. Sementara itu, pasokan dari luar daerah terus meningkat pada tahun ke 4 hingga ke 10. Fluktuasiharga terjadi, tahun ke 3 hHarga lele mengalami penurunan akibat banyaknya produksi lokal terjadi padatahun ke-3., namun pPada tahun ke 5 harga mengalami kenaikan akibat kekurangan pasokan. Olehkarena itu, diperlukan kebijakan peningkatan produktivitas dan pendapatan usaha budidaya lele denganmemanfaatkan lahan-lahan potensial maupun meningkatan produktifitas usaha.Title: Constructive Design for Catfish Aquaculture DevelopmentPolicy Through Dynamic Model ApproachCatfish is one of the priority product of fisheries commodity in “Minapolitan” Program introducedby the Ministry of Marine Affairs and Fisheries, particularly in Gunungkidul District, Yogyakarta Province.The study was conducted during 2011 to 2012. .This study aimed to construct the policy model for Catfishaquaculture development to support aquaculture production by using dynamic modelling approache.Technique analysis assumed that Catfish demand will increase when existing fisheries system could bemaintained. Finding shows that the demand sharply increased on the fourth year of project. Meanwhile,Catfish supply from other region would be increase on the fourth year and tenth year. Catfish price hasdecreased on the third year due to over supply of local production. However, Catfish price increasedon the fifth year due to less supply of the local product. Therefore, appropriate strategies needed toencourage increased productivity and farmers income by revitalize the potential land and increasebusiness productivity.

System Transition to the “Eco-Finance” Sustainable Growth: Evidence from Chinese and Russian Oil and Gas Companies

2019 ◽  
Vol 2019 (4) ◽  
pp. 42-59
Author(s):  
Alina Стеблянская ◽  
Vang Zhen ◽  
Nailya Gabdrahmanova ◽  
Uvais Aleroev
Keyword(s):  
Dynamic Model ◽  
Ricci Curvature ◽  
Growth Model ◽  
Oil And Gas ◽  
Dynamic Modelling ◽  
Growth Index ◽  
Oil And Gas Industry ◽  
Sustainable Growth ◽  
System Transition ◽  
Oil And Gas Companies

In this paper, we study how financial sustainable growth matters for environment protection and social responsibility. Financial decisions that take into account long-term social and environmental consequences should be central to the system of financially sustainable growth of oil and gas companies of the world, including Russia and China. Authors present Russia and China oil and gas industry system transition to «Green Finance» sustainable growth model results with interrelation financial, environmental and social factors. Study regarded in the context of economic growth theory, system economics theory and the theory of relativity. It was created Python 3.6. financial sustainable growth model for Russia and China. A dynamic model was built on the basis of the Ricci tensor. For sustainable growth intensity analysis, it was compared Financial sustainable index (FSI), Higgins’ sustainable growth rate (SGR), Ivashkovskaya’ sustainable growth index (SGI), Ivashkovskaya’ sustainable growth index modification (SGImodif) every period indicators’ average values and the graph’ average values of the Ricci curvatures (R). Using the Ricci curvature, the parameters of a dynamic model of sustainable growth are determined for Russia and for China oil and gas industry.Key words: sustainable growth, System Dynamic modelling, Ecological Finance, Ricci Curvature, environmental financial sustainable growth, Financial Sustainable Index (FSI).

scholarly journals Dynamic Modelling Transformations for the Low Earth Orbit Satellite Particulate Environment

1991 ◽  
Vol 126 ◽  
pp. 37-40
Author(s):  
J.A.M. McDonnell ◽  
K. Sullivan ◽  
S.F. Green ◽  
T.J. Stevenson ◽  
D.H. Niblett
Keyword(s):  
Dynamic Model ◽  
Space Debris ◽  
Residue Analysis ◽  
Dynamic Modelling ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Natural Orbital ◽  
Low Earth Orbit Satellite ◽  
Chemical Residue ◽  
Particle Velocities

AbstractA simple dynamic model to investigate the relative fluxes and particle velocities on a spacecraft’s different faces is presented. The results for LDEF are consistent with a predominantly interplanetary origin for the larger particulates, but a sizable population of orbital particles with sizes capable of penetrating foils of thickness <30μm. Data from experiments over the last 30 years do not show the rise in flux expected if these were space debris. The possibility of a population of natural orbital particulates awaits confirmation from chemical residue analysis.

scholarly journals 3D-Dynamic Modelling and Performance Analysis of Service Behavior for Beam Pumping Unit

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Feng Zi-Ming ◽  
Tan Jing-Jing ◽  
Sun Yanan ◽  
Zhang De-Shi ◽  
Duan Wei-Bo
Keyword(s):  
Partial Differential Equations ◽  
Performance Analysis ◽  
Dynamic Model ◽  
Dynamic Modelling ◽  
Oil Well ◽  
Working Process ◽  
Pumping Wells ◽  
Torque Curve ◽  
Service Behavior ◽  
And Performance

In consideration of the rod, the tube, and the liquid column, a 3D dynamic model was established, which could be expressed as a set of partial differential equations. A measured torque curve and a calculated torque curve of Nan1-2-22 oil-well in Daqing oilfield were contrasted with each other which improved the rationality of this model. At last, we researched the influence of the stroke and the frequency of stroke on the displacement of rod, suspension velocity, suspension acceleration, polish rod load, and net torque of gearbox. This 3D dynamic model has a higher calculated accuracy and veracity and could be used to design and optimize the structure of rod pumping and the working process of pumping wells.

scholarly journals Dynamic modelling of cold-hardiness in tea buds by imitating past temperature memory

2020 ◽  
Author(s):  
Kensuke Kimura ◽  
Daisuke Yasutake ◽  
Takahiro Oki ◽  
Koichiro Yoshida ◽  
Masaharu Kitano
Keyword(s):  
Cold Stress ◽  
Cold Acclimation ◽  
Dynamic Model ◽  
Cold Hardiness ◽  
Global Climate ◽  
Effective Means ◽  
Dynamic Modelling ◽  
Short Term ◽  
Mean Square Errors

Abstract Background and Aims Most perennial plants memorize cold stress for a certain period and retrieve the memories for cold acclimation and deacclimation, which leads to seasonal changes in cold-hardiness. Therefore, a model for evaluating cold stress memories is required for predicting cold-hardiness and for future frost risk assessments under warming climates. In this study we develop a new dynamic model of cold-hardiness by introducing a function imitating past temperature memory in the processes of cold acclimation and deacclimation. Methods We formulated the past temperature memory for plants using thermal time weighted by a forgetting function, and thereby proposed a dynamic model of cold-hardiness. We used the buds of tea plants (Camellia sinensis) from two cultivars, ‘Yabukita’ and ‘Yutakamidori’, to calibrate and validate this model based on 10 years of observed cold-hardiness data. Key Results The model captured more than 90 % of the observed variation in cold-hardiness and predicted accurate values for both cultivars, with root mean square errors of ~1.0 °C. The optimized forgetting function indicated that the tea buds memorized both short-term (recent days) and long-term (previous months) temperatures. The memories can drive short-term processes such as increasing/decreasing the content of carbohydrates, proteins and antioxidants in the buds, as well as long-term processes such as determining the bud phenological stage, both of which vary with cold-hardiness. Conclusions The use of a forgetting function is an effective means of understanding temperature memories in plants and will aid in developing reliable predictions of cold-hardiness for various plant species under global climate warming.

Dynamic Analysis of a Towed Underwater Vehicle System: Model Validation

2004 ◽  
Author(s):  
Gry Karin Haugen ◽  
Mads Grahl-Madsen
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
Dynamic Behaviour ◽  
Equations Of Motion ◽  
Underwater Vehicle ◽  
Integrated System ◽  
System Model ◽  
Cable Model ◽  
Vehicle System ◽  
Successful Design

An integrated system consisting of two towed sub-sea vehicles and a free-floating probe is being developed to perform mapping and quantitative estimations for fish and plankton. A thorough understanding of the dynamic behaviour of the towed vehicle system is essential for a successful design, and a dynamic model that can accurately describe the vehicle behaviour under the influence of a wide variation of conditions, is necessary. This paper discusses two different approaches for the dynamic analysis of a towed vehicle system. Analyses are performed using the commercial available simulation program MOSES. Further the 2D equations of motion for the towed vehicle are developed and solved in Matlab using a simple cable model.

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