scholarly journals Description of selected pneumatic elements and systems using fractional calculus

2019 ◽  
Vol 1 (1) ◽  
pp. 43-49
Author(s):  
Daniel Pietruszczak ◽  
Artur Nowocień

The paper presents the application of fractional calculus to describe the dynamics of selected pneumatic elements and systems. In the construction of mathematical models of the analysed dynamic systems, the Riemann-Liouville definition of differintegral of non- integer order was used. For the analysed model,  transfer function of integer  and non-integer order was determined. Functions describing characteristics in frequency domains were determined,  whereas the characteristics of the elements and systems were obtained by means of computer simulation. MATLAB programme were used for the simulation research.

2018 ◽  
Vol 19 (12) ◽  
pp. 514-525
Author(s):  
Mirosław Luft ◽  
Artur Nowocień ◽  
Daniel Pietruszczak

The paper presents the application of the fractional calculus to describe the dynamics of selected basic elements of automation. For the analyzed models, the integer and non-integer order transmittance was determined. Relationships describing time characteristics were determined and frequency; on the path of computer simulation, the characteristics of the analyzed systems were obtained. MATLAB software was used for simulation research.


2019 ◽  
Vol 254 ◽  
pp. 02021
Author(s):  
Jacek Marcinkiewicz ◽  
Jarosław Selech ◽  
Żaneta Staszak ◽  
Łukasz Gierz ◽  
Dariusz Ulbrich ◽  
...  

The paper presents the results of research aimed at the verification of the existing design solutions of four example sowing units for agricultural seed drills with the most frequently used types of sowing wheels. The research was conducted with the use of modern computer simulation systems based on the discrete element method (DEM) with the evaluation of the efficiency of selected design solutions in terms of achieved performance and metering uniformity. The paper includes a description of virtual research models and the employed mathematical models used for mirroring contact between seeds. Moreover, for the purpose of verification of the obtained results, bench tests were conducted using actual models of selected design solutions.


2020 ◽  
pp. 3-11
Author(s):  
S.M. Afonin

Structural-parametric models, structural schemes are constructed and the transfer functions of electro-elastic actuators for nanomechanics are determined. The transfer functions of the piezoelectric actuator with the generalized piezoelectric effect are obtained. The changes in the elastic compliance and rigidity of the piezoactuator are determined taking into account the type of control. Keywords electro-elastic actuator, piezo actuator, structural-parametric model, transfer function, parametric structural scheme


2016 ◽  
Vol 14 (1) ◽  
pp. 1122-1124 ◽  
Author(s):  
Ricardo Almeida ◽  
Małgorzata Guzowska ◽  
Tatiana Odzijewicz

AbstractIn this short note we present a new general definition of local fractional derivative, that depends on an unknown kernel. For some appropriate choices of the kernel we obtain some known cases. We establish a relation between this new concept and ordinary differentiation. Using such formula, most of the fundamental properties of the fractional derivative can be derived directly.


2021 ◽  
Vol 5 (2) ◽  
pp. 35
Author(s):  
Haci Mehmet Baskonus ◽  
Luis Manuel Sánchez Ruiz ◽  
Armando Ciancio

Mathematical models have been frequently studied in recent decades in order to obtain the deeper properties of real-world problems [...]


Author(s):  
Sheng Meng ◽  
Man Zhang

Abstract This study numerically investigates the effect of spray-wall interactions on thermoacoustic instability prediction. The LES-based flame transfer function (FTF) and the convective time delay methods are used by combining the Helmholtz acoustic solver to predict a single spray flame under the so-called slip and film spray-wall conditions. It is found that considering more realistic film liquid and a wall surface interaction model achieves a more accurate phase lag in both of the time lag evaluations compared to the experimental results. Additionally, the results show that a new time delay exists between the liquid film fluctuation and the unsteady heat release, which explains the larger phase value in the film spray-wall condition than in the slip condition. Moreover, the prediction capability of the FTF framework and the convective time delay methodology in the linear regime are also presented. In general, the instability frequency differences predicted using the FTF framework under the film condition are less than 10 Hz compared with the experimental data. However, an underestimation of the numerical gain value leads to requiring a change in the forcing position and an improvement in the numerical models. Due to the ambiguous definition of the gain value in the convective time delay method, this approach leads to arbitrary and uncertain thermoacoustic instability predictions.


2021 ◽  
Vol 24 (4) ◽  
pp. 1003-1014
Author(s):  
J. A. Tenreiro Machado

Abstract This paper proposes a conceptual experiment embedding the model of a bouncing ball and the Grünwald-Letnikov (GL) formulation for derivative of fractional order. The impacts of the ball with the surface are modeled by means of a restitution coefficient related to the coefficients of the GL fractional derivative. The results are straightforward to interpret under the light of the classical physics. The mechanical experiment leads to a physical perspective and allows a straightforward visualization. This strategy provides not only a motivational introduction to students of the fractional calculus, but also triggers possible discussion with regard to the use of fractional models in mechanics.


2018 ◽  
Vol 155 ◽  
pp. 01041 ◽  
Author(s):  
Aleksandr Pilipenko ◽  
Sergei Petrov

In the article the authors solve a crucial objective of reducing the cost of heating services through the introduction of a system, controlling boilers and heating devices, based on modelling of the building and predicting heating systems functioning and operation. The authors describe the method of mathematical modelling of heating systems of the building and represent the developed mathematical models, pledged and installed into the developed automated system. The authors have offered an automated system of dispatch control of the boilers with the elements of computer simulation and modelling.


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