Authors:Mohamed Tahiri, Abdellatif Khamlichi and Mohammed Bezzazi
Due to the extensive development of high-speed railway lines which are operating at increasing velocities, the dynamic performance of railway bridges has become an important issue of scientific research. The aim of this study is to investigate the possibility of reducing the vertical acceleration and displacement of pre-stressed reinforced concrete bridges beams by using passive nonlinear viscoelastic dampers to retrofit them. The proposed solution is based on connecting the dampers directly to the abutments and the bottom surface of the bridge deck with an eccentricity between the neutral axis of the bridge and the contact point of the viscoelastic dampers. First, the dampers are modeled through the concept of linearized fractional derivatives to obtain energetic equivalent linear viscoelastic dampers. Optimization of the configuration of these dampers was performed then as function of the orientation angle and the eccentricity. Considering two bridges having different length that were studied in the literature with other systems of damping, it was found that the best orientation angle of dampers is close to 60°. It was found also that, in order to satisfy Eurocode 1 requirements, the total equivalent damping coefficient for the actual damping system is less than half of that required for systems using auxiliary beam to fix dampers, which indicates higher efficiency of the proposed solution.
The rooms of each building can be interpreted as three-dimensional cells. Borders (sides, edges) of rooms can be identified as the two-, one-, or zero-dimensional boundary cells of the three dimensional cell. The building structures identified as two-, one-, or zero-dimensional cells can be modeled by distinguished geometrical forms, surface-, line-, and point-like bodies. In accordance with the latter, building materials (finished products) can also be considered as surface-, line-, and point-like bodies.
The aim of the study is to create compliance between the cell elements and the building structures. It will be done at different levels:
– interpretation of relationship between building construction and cells,
– interpretation of relationship between building construction and selected bodies,
– interpretation the loadbearing's structure using cells,
– structure of the surface-construction and the cells,
– interpretation building types using cells.
In this paper (as part I) the first two items will be studied. The other three cases will be studied in another paper (as part II).
Authors:David Torma, Gyula Gyori and Kornil Sarvajcz
The research team has developed a complex system that is capable to record and analyse various psychophysiological data. This article represents the program created in NI DIAdem which can automatically identify illnesses and generate reports based on the input and saved parameters. The created program can import data from different types of file formats. It is converted and saved in a new standardized format for further processing. It can play-back the processed data synchronized with adjustable speed, and visualize them on customized display areas. It can analyse the data based on the input parameters and the pre-defined mathematical equations. The program displays the input and calculated parameters, the results and the detected illnesses on automatically generated reports.
Authors:Munaf Fathi Badr, Ekhlas Hameed Karam and Noor Mohammaed Mjeed
The objective of this paper is to present a proposed control model for the electromechanical damper mass spring system including the backstepping technique in comparison with the conventional proportional–derivative–integral (PID) controller unit to realize the best performance of the control systems. The suggested approach demanded the construction in laboratory arrangement of damper mass spring system which linked with electrical position sensor, and the theoretical work involved the derivation of the required mathematical equations in order to formulate the simulation models in Matlab software package. The obtained results show that the backstepping control technique provides the better performance associated with stable control system especially with increasing the value of selected mechanical load.
In the recently published researches in the object localization field, 3D object localization takes the largest part of this research due to its importance in our daily life. 3D object localization has many applications such as collision avoidance, robotic guiding and vision and object surfaces topography modeling. This research study represents a novel localization algorithm and system design using a low-resolution 2D ultrasonic sensor array for 3D real-time object localization. A novel localization algorithm is developed and applied to the acquired data using the three sensors having the minimum calculated distances at each acquired sample, the algorithm was tested on objects at different locations in 3D space and validated with acceptable level of precision and accuracy. Polytope Faces Pursuit (PFP) algorithm was used for finding an approximate sparse solution to the object location from the measured three minimum distances. The proposed system successfully localizes the object at different positions with an error average of ±1.4 mm, ±1.8 mm, and ±3.7 mm in x-direction, y-direction, and z-direction, respectively, which are considered as low error rates.
The fourth industrial revolution, often identified as the terminology of Industry 4.0, more and more enforces changes and modifications from each participant of the socio-economic ecosystem. These enforced corrections concern the households, the governmental areas in different degrees, but the operation of the company sectors is rearranged most strongly by them. The study analyses this latter structure in the following respect: which are the most important supports of Industry 4.0 and what kind of competency elements are required from the employees and the management? According to the research data to be introduced, the domestic companies lag behind in preparations for the challenges raised by Industry 4.0; the international experiences are more favourable in this field. After—partial—review of the professional literature, the author concludes that the business sphere is in a condition before paradigm shift due to Industry 4.0. As per the analysis of decision-making based on digitalization, the question in the subtitle is answered—Industry 4.0 does not change fundamentally the traditional management functions of the company sector, but the decision-supporting applications based on digitalization must be learnt and applied. That statement seems to be founded that only company management, being able to live with decision making based on digitalization, can win competitive advantage.
Today, the use of proportional-integral-derivative (PID) control units continues in many control applications due to their simple structure. In areas such as pressure, temperature, flow control, PID control element is used and many new methods are applied in adjusting control parameters. In this study, the LTR 701 Controlled Airflow and Temperature Experimental System was used to study the temperature and pressure control at different flow rates in the pipelines. In this control system, temperature was controlled with PID control element, pressure was controlled with PI control element, and reaction of control parameters at different temperatures and pressures were investigated. Also, temperature was controlled as cascade with PI element in elementary controller and P element in secondary controller. The manual adjustment method has been applied to adjust the control parameters. In addition, the experimental system is modelled in MATLAB-SIMULINK. On this model, simulation results showed that it is matching the experimental results.
Authors:Barhm Mohamad, Jalics Karoly, Andrei Zelentsov and Salah Amroune
In this work a multilevel Computational Fluid Dynamics (CFD) analysis has been applied for the design of a Formula race car exhaust muffler with improved characteristics of sound pressure level (SPL) and fluid dynamic response. The approaches developed and applied for the optimization process range from the 1D to fully 3D CFD simulation, exploring hybrid approaches based on the integration of a 1D model with 3D tools. Modern mufflers typically have a complex system of chambers and flow paths. There are a variety of sound damping and absorbing mechanisms working to quiet the sound flowing through a muffler and piping system. Two calculation methods were selected for this study. The muffler has a complex inner structure containing perforated pipe and fiber material. Computer-aided design (CAD) file of the muffler was established for developing Finite Element Analysis (FEA) model in AVL BOOST v2017 and another commercial advanced design software (SolidWorks 2017). FEA model was made to monitor the flow properties, pressure and velocity. After the model was verified, sensitivity studies of design parameters were performed to optimize the SPL of the muffler. The software analysis results are included in the paper. Recommendations are made for obtaining smoother SPL curves for various measurement methods.
Authors:Mariam Achbal, Abdellatif Khamlichi and Fadoua El Khannoussi
In this work, a numerical method is proposed in order to achieve design optimisation of phased array (PA) probes for the special application of defects detection in thin films. This approach relies on an extended Fourier-based model that was adapted to predict the two-dimensional ultrasonic displacement field taking place in a thin plate under individual excitation of PA probe elements which have arbitrary orientation with respect to the examined part surface. Excitation is applied through a fluid couplant and is operated at scheduled delays that are managed to enable emission of constructive pulses. This gives the possibility to steer sound waves towards a direction and to focalize the beam in a selected point. An optimisation algorithm based on the concept of pattern search that does not require evaluation of a gradient was used to find the best match in the multidimensional analysis space of possibilities including the elements orientation angles, the elements lengths, the inter-elements distances and work frequency. Optimisation was performed with the objective to maximize the displacement amplitude at the focal point while minimizing simultaneously the effect of beam side lobes. The results obtained by this approach reveal that focalisation can be achieved with enhanced features in comparison with previous algorithms assuming linear elements that are parallel to the surface of the plate.