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Number of results: 14
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Abstract

This paper presents a complex study of anhydrite interbeds influence on the cavern stability in the Mechelinki salt deposit. The impact of interbeds on the cavern shape and the stress concentrations were also considered. The stability analysis was based on the 3D numerical modelling. Numerical simulations were performed with use of the Finite Difference Method (FDM) and the FLAC3D v. 6.00 software. The numerical model in a cuboidal shape and the following dimensions: length 1400, width 1400, height 1400 m, comprised the part of the Mechelinki salt deposit. Three (K-6, K-8, K-9) caverns were projected inside this model. The mesh of the numerical model contained about 15 million tetrahedral elements. The occurrence of anhydrite interbeds within the rock salt beds had contributed to the reduction in a diameter and irregular shape of the analysed caverns. The results of the 3D numerical modelling had indicated that the contact area between the rock salt beds and the anhydrite interbeds is likely to the occurrence of displacements. Irregularities in a shape of the analysed caverns are prone to the stress concentration. However, the stability of the analysed caverns are not expected to be affected in the assumed operation conditions and time period (9.5 years).

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Authors and Affiliations

Marek Cała
ORCID: ORCID
Katarzyna Cyran
ORCID: ORCID
Michał Kowalski
ORCID: ORCID
Paweł Wilkosz
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Abstract

In the paper we propose a fractional-piecewise-constant-order PID controller and discuss the stability and robustness of a closed loop system. In stability analysis we use the transform method and include the Nyquist-like criteria. Simulations for designed controllers are performed for the second-order plant with a delay.
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Bibliography

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  9.  S. Debarma, L.C. Saikia, and N. Sinha, “Automatic generation control using two degree of freedom fractional order PID controller”, Int. J. Electr. Power Energy Syst., vol. 58, pp. 120–129, 2014.
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Authors and Affiliations

Piotr Oziablo
1
Dorota Mozyrska
1
Malgorzata Wyrwas
1

  1. Bialystok University of Technology, ul. Wiejska 45A, 15-351 Bialystok, Poland
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Abstract

In this paper, the observer design problem for a T-S fuzzy bilinear control system is investigated. First, an observer of Kalman type is designed to estimate the system states for the linear case. Then, some new sufficient conditions are derived to show the exponential convergence of the solutions of the error equation for fuzzy bilinear systems. Furthermore, we consider some uncertainties of the system that are bounded and satisfy a certain condition where an observer is designed. Moreover, an application to Van de Vusse system is given.
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Authors and Affiliations

François Delmotte
1
Nizar Hadj Taieb
2
Mohamed Ali Hammami
3
Houria Meghnafi
3

  1. University of Artois, Bethune, France
  2. University of Sfax, IPEIS Sfax, Tunisia
  3. University of Sfax, Faculty of Sciences of Sfax, Tunisia
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Abstract

In this article, an engineering/physical dynamic system including losses is analyzed inrelation to the stability from an engineer’s/physicist’s point of view. Firstly, conditions for a Hamiltonian to be an energy function, time independent or not, is explained herein. To analyze stability of engineering system, Lyapunov-like energy function, called residual energy function is used. The residual function may contain, apart from external energies, negative losses as well. This function includes the sum of potential and kinetic energies, which are special forms and ready-made (weak) Lyapunov functions, and loss of energies (positive and/or negative) of a system described in different forms using tensorial variables. As the Lypunov function, residual energy function is defined as Hamiltonian energy function plus loss of energies and then associated weak and strong stability are proved through the first time-derivative of residual energy function. It is demonstrated how the stability analysis can be performed using the residual energy functions in different formulations and in generalized motion space when available. This novel approach is applied to RLC circuit, AC equivalent circuit of Gunn diode oscillator for autonomous, and a coupled (electromechanical) example for nonautonomous case. In the nonautonomous case, the stability criteria can not be proven for one type of formulation, however, it can be proven in the other type formulation.
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Authors and Affiliations

Cim Civelek
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Abstract

Electro-dynamic passive magnetic bearings are now viewed as a feasible option when looking for support for high-speed rotors. Nevertheless, because of the skew-symmetrical visco-elastic properties of such bearings, they are prone to operational instability. In order to avoid this, the paper proposes the addition of external damping into the newly designed vibrating laboratory rotor-shaft system. This may be achieved by means of using simple passive dampers that would be found among the components of the electro-dynamic bearing housings along with magnetic dampers, which satisfy the operational principles of active magnetic bearings. Theoretical investigations are going to be conducted by means of a structural computer model of the rotor-shaft under construction, which will take into consideration its actual dimensions and material properties. The additional damping magnitudes required to stabilize the most sensitive lateral eigenmodes of the object under consideration have been determined by means of the Routh-Hurwitz stability criterion.

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Authors and Affiliations

T. Szolc
F. Falkowski
M. Henzel
P. Kurnyta-Mazurek
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Abstract

This paper presents control method for multiple two-wheeled mobile robots moving in formation. Trajectory tracking algorithm from [7] is extended by collision avoidance, and is applied to the different type of formation task: each robot in the formation mimics motion of the virtual leader with a certain displacement. Each robot avoids collisions with other robots and circular shaped, static obstacles existing in the environment. Artificial potential functions are used to generate repulsive component of the control. Stability analysis of the closed-loop system is based on Lyapunov-like function. Effectiveness of the proposed algorithm is illustrated by simulation results.

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Authors and Affiliations

W. Kowalczyk
K. Kozłowski
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Abstract

The main idea of this work is to demonstrate an application of the generalized perturbation-based Stochastic Finite Element Method for a determination of the reliability indicators concerning elastic stability for a certain spectrum of the civil engineering structures. The reliability indicator is provided after the Eurocode according to the First Order Reliability Method, and computed using the higher order Taylor expansions with random coefficients. Computational implementation provided by the hybrid usage of the FEM system ROBOT and the computer algebra system MAPLE enables for reliability analysis of the critical forces in the most popular civil engineering structures like simple Euler beam, 2 and 3D single and multi-span steel frames, as well as polyethylene underground cylindrical shell. A contrast of the perturbation-based numerical approach with the Monte-Carlo simulation technique for the entire variability of the input random dispersion included into the Euler problem demonstrates the probabilistic efficiency of the perturbation method proposed.

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Authors and Affiliations

M. Kamiński
P. Świta
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Abstract

In this work, we present new results for a two-scroll 4-D hyperchaotic system with a unique saddle point equilibrium at the origin. The bifurcation and multi-stability analysis for the new hyperchaotic system are discussed in detail. As a control application, we develop a feedback control based on integral sliding mode control (ISMC) for the complete synchronization of a pair of two-scroll hyperchaotic systems developed in this work. Numerical simulations using Matlab are provided to illustrate the hyperchaotic phase portraits, bifurcation diagrams and synchronization results. Finally, as an electronic application, we simulate the new hyperchaotic system using Multisim for real-world implementations.
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Authors and Affiliations

Sundarapandian Vaidyanathan
1
Irene M. Moroz
2
Aceng Sambas
3 4

  1. Centre for Control Systems, Vel Tech University, 400 Feet Outer Ring Road, Avadi, Chennai-600092, Tamil Nadu, India
  2. Mathematical Institute, University of Oxford, Andrew Wiles Building, ROQ, Oxford Ox2 6GG, UK
  3. Faculty of Informatics and Computing, Universiti Sultan Zainal Abidin, Gong Badak, 21300, Terengganu, Malaysia
  4. Department of Mechanical Engineering, Universitas MuhammadiyahTasikmalaya, Tasikmalaya 46196,West Java, Indonesia
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Abstract

In this paper, the typical sand-conglomerate uranium ore in north China was taken as the research object. The uniaxial compression and tensile tests of sand-conglomerate specimens under natural status and acidic solution status were used to research the compressive strength, tensile strength, Young’s modulus, cohesion and internal friction angle. Focusing on this type of uranium deposit, during the underground design of the in-situ leaching mining method, the three-dimensional finite element method was used to conduct a numerical simulation of the liquid collecting tunnel with different structural parameters of 10 m×2 m, 3 m×2 m, 2 m×2 m, and comprehensively analyse the vertical displacement, principal stress and plastic deformation zone changes of the tunnelbefore and after leaching. Based on the results, influenced by an acidic aqueous solution, the grain of the conglomerate became soft and secondary pores appeared, resulting in the superimposed effect of physical damage and chemical damage. Macroscopically, an obvious decrease was witnessed in mechanical property. Based on the stability and economy factor of three scenarios before and after leaching, the scenario was recommended as the experimental testing scenario, specifically, two longitudinal collecting tunnel were arranged along the strike of the orebody, with the size of 3 m×2 m and the width of the middle pillar of 4 m. The results of the numerical simulation are significant in guiding the design of underground in-situ leaching technology and determining the structural parameters of the deposit.
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Authors and Affiliations

Yulong Liu
1 2
Lei Huang
2
Guicheng He
1
Nan Hu
1
Shuhui Zhou
2
Qing Yu
1
Dexin Ding
1

  1. Key Discipline Laborat ory for Nat ional Defensefor Biotechnology in Uranium Mining and Hydrometa llurgy, University of South China, China
  2. China General Nuclear Power Group (CGN) Uranium Resources Co., Ltd, Beijing 100029, China
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Abstract

Through partially replacing Y element, Ce was added into near-equiatomic AlNiY medium-entropy amorphous alloy (denoted as MEAA) ribbons by the melt spinning process in this study. The differences of microstructure, thermal stability, hardness and corrosion resistance of Al33.3Ni33.3Y33.4-xCex (x = 0, 2, 5, 8, 13) alloy ribbons were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimeter (DSC) and Vickers-type hardness tester. The anti-corrosion performance in 3.5 wt.% NaCl solution of alloy ribbons was investigated elaborately through the general potentiodynamic polarization curves (Tafel) and electrochemical impedance spectroscopy (EIS). Results suggested that all ribbon samples could remain amorphous structure and the hardness are all above 510 HV0.1. With the increase of Ce content, the thermal stability begins to be gradually lower. However, according to the analysis of crystallization kinetics, all types of MEAA ribbons presents the relatively prominent thermal stability compared with traditional Al-based amorphous alloys. The corrosion current density raises firstly, then shows a decreasing trend, and has a slight increase at last. Therefore, appropriate content of Ce element can improve the corrosion protection performance of alloy ribbons and the 5 at.% Ce MEAA ribbons exhibited the excellent corrosion resistance in this study.
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Authors and Affiliations

Shuyan Zhang
1 2
ORCID: ORCID
Zhibin Zhang
2
Xin Wang
2
Yangyang Gao
1
Xiubing Liang
1
ORCID: ORCID

  1. Zhejiang University, Ocean College, Zhoushan 316021, Peoples Republic of China
  2. Defense Innovation Institute, Academy of Military Sciences of The PLA of China, Beijing 100071, Peoples Republic of China
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Abstract

An active inerter-based suspension with acceleration feedback control is proposed in this paper, the time delay generated in the controllers and actuators is considered, which constitutes the time-delayed active inerter-based (TDA-IB) suspension. The dynamic equation of the TDA-IB suspension is established and is a neutral type of delay differential equation (NDDE) in which the time delay exists in the highest-order derivative. The stability analysis is conducted by calculating the number of unstable characteristic roots based on the definite integral stability method, the stable and unstable regions are determined. The effect of time delay and feedback gain on the dynamic performance of the TDA-IB suspension under harmonic, random, and shock excitations is studied in detail and compared with the parallel-connected inerter-based (PC-IB) and traditional suspensions. The results show that the TDA-IB suspension is asymptotically stable for smaller feedback gain and time delay, through increasing the feedback gain, the stable regions shrink, and a smaller time delay could cause the system to become unstable. Furthermore, the time delay could regulate the resonance peak around the unsprung mass natural frequency and generate multiple high-frequency resonance peaks. If the time delay is chosen appropriately and falls into the stable range, the TDA-IB suspension could improve the dynamic performance for the suspension stroke and dynamic tire load while having a deterioration for the vehicle body acceleration compared with the PC-IB and traditional suspensions.
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Authors and Affiliations

Yong Wang
1 2 3
ORCID: ORCID
Xian-Yu Jin
1
Yun-Shun Zhang
1
Hu Ding
4
Li-Qun Chen
4

  1. Automotive Engineering Research Institute, Jiangsu University, Zhenjiang 212013, China
  2. Vehicle Measurement, Control and Safety Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, China
  3. Provincial Engineering Research Center for New Energy Vehicle Intelligent Control and Simulation Test Technology of Sichuan, Xihua University, Chengdu 610039, China
  4. School of Mechanics and Engineering Science, Shanghai University, Shanghai 200444, China
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Abstract

In the formulation, the existence, uniqueness and stability of solutions and parameter perturbation analysis to Riemann-Liouville fractional differential equations with integro-differential boundary conditions are discussed by the properties of Green’s function and cone theory. First, some theorems have been established from standard fixed point theorems in a proper Banach space to guarantee the existence and uniqueness of positive solution. Moreover, we discuss the Hyers-Ulam stability and parameter perturbation analysis, which examines the stability of solutions in the presence of small changes in the equation main parameters, that is, the derivative order η, the integral order β of the boundary condition, the boundary parameter ξ , and the boundary value τ. As an application, we present a concrete example to demonstrate the accuracy and usefulness of the proposed work. By using numerical simulation, we obtain the figure of unique solution and change trend figure of the unique solution with small disturbances to occur in different kinds of parameters.
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Authors and Affiliations

Nan Zhang
1
Lingling Zhang
2
ORCID: ORCID
Mercy Ngungu
3
Adejimi Adeniji
4
Emmanuel Addai
2

  1. College of Mathematics, Taiyuan University of Technology, 030024, TaiYuan, Shanxi, ChinaCollege of Mathematics, Taiyuan University of Technology, 030024, TaiYuan, Shanxi, China
  2. College of Mathematics, Taiyuan University of Technology, 030024, TaiYuan, Shanxi, China
  3. Human Sciences Research Council (HSRC), South Africa
  4. Tshwane university of Technology, South Africa
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Abstract

Landslide is a common geological disaster which causes huge losses to people’s properties and national economic development. How to prevent and control landslides has become an important issue. This article introduces the geological and geographical environment of the landslide body, analyzes the basic characteristics of the landslide, calculates the landslide stability based on the ultimate equilibrium theory-based transfer coefficient method, discusses the development trend of the landslide and comes up with corresponding control schemes by taking the landslide body of Black Bovine Cave Copper Ore Mining & Beneficiation Project as example. It is found that the control scheme – “anti-slide pile + retraining wall + baffle + anchor cable” can be used to effectively prevent and control the geological disaster according to calculation. The study results can provide a reference for landslide body control.
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Authors and Affiliations

Hanhui Wu
1
ORCID: ORCID

  1. Civil Engineering, School of Civil Engineering, Chongqing Chemical Industry Vocational College, 400020 Chongqing, China
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Abstract

The main goal of introducing Active Suspension System in vehicles is to reduce the vehicle body motion under road obstacles which improves the ride comfort of the passenger. In this paper, the Full Car Model (FCM) with seven Degrees of Freedom is considered and simulated by MATLAB/Simulink. The Terminal Sliding Mode Controller (TSMC) and Fractional Order Terminal Sliding Mode Controller (FOTSMC) are designed to enhance the ride quality, stability and passenger comfort for FCM. The designed FOTSMC has the ability to provide higher control accuracy in a finite time. The performances of the designed controllers are evaluated by measuring the vehicle body vibration in both angular and vertical direction under bump input and ISO-8608 random input against passive suspension system. The FrequencyWeighted Root Mean Square (FWRMS) and Vibration dose value of Body Acceleration as per ISO-2631 are evaluated for FOTSMC, TSMC and PSS. The stability of the FCM is proved by Lyapunouv theory. Further analysis with sprung mass and speed variation of FCM demonstrate the robustness of proposed controller. To investigate the performances of designed controllers, comparison is made with existing Sliding Mode Controller (SMC) which proves that the designed FOTSMC performs better than existing SMC.

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Authors and Affiliations

T. Yuvapriya
P. Lakshmi
S. Rajendiran

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