DIAGNOSTYKA Vol. 17, No. 4 (2016)
Table of contents - SCIENTIFIC PAPERS
Pages : 3-17

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Abstract (EN)

The main aim of the present paper is the implementation of a fault detection strategy to ensure the fault detection in a gas turbine which is presenting a complex system. This strategy is based on an adaptive hybrid neuro fuzzy inference technique which combines the advantages of both techniques of neuron networks and fuzzy logic, where, the objective is to maintain the desired performance of the studied gas turbine system in the presence of faults. On the other side,  the representation of fuzzy knowledge in the learning neural networks has to be accurate to provide significant improvements for modeling of the studied system dynamic behavior. The results presented in this paper proves clearly that the proposed detection technique allows the perfect detection of the studied gas turbine malfunctions, furthermore it shows that the use of the proposed technique based on the Adaptive Neuro-Fuzzy Interference System (ANFIS) approach which uses the adaptive learning mechanism of neuron networks and fuzzy inference techniques, can be a promising technique to be applied in several industrial application for faults detection.

Pages : 19-25

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Abstract (EN)
Supervisory Control And Data Acquisition (SCADA) systems have recently become ubiquitous in wind energy technology. SCADA data analysis actually can provide considerable performance improvement at low cost. This also boosts wind energy exploitation, because it enlarges short and long term economic sustainability of investments. Nevertheless, SCADA data analysis poses several scientific and technological challenges, mostly related to the vastness of the data sets required for significant analysis. Separating the signal from the noise is therefore a complex task. In the present work, this issue is tackled by the point of view of state dynamics of wind turbines. SCADA control systems often record superabundant and ambiguous information. Therefore, in this work it is shown that hierarchical classification of information and time discretization of the continuous motion of states are powerful tools. The time-discretized state dynamics is processed in the formulation of several indices for performance evaluation and fault diagnosis. The method is tested on the data set of a wind farm owned by Renvico s.r.l. and sited in Italy.

Susanna PAPINI, Maria Cristina VALIGI
Pages : 27-32

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Abstract (EN)
The paper represents an extension of a previous work where the problem of chatter in a rolling mill producing advanced high-strength steels (AHSS) was investigated by a combination of a linear lumped parameter model and the slab analysis. In this paper the authors show the detailed experimental study of the problem with a complete description of all the phases related to the vibrational investigation that lead to the solution of the problem. Furthermore, a different model based on the Orowan’s method together with a non-linear model of the rolling mill is presented and simulations are performed.

Łukasz LECH, Marek IWANIEC, Joanna IWANIEC
Pages : 33-38

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Abstract (EN)
The paper presents theoretical basis for identification of nonlinear systems using the method based on Hilbert transform. Discussed method was verified by analyzing the synthesized signals of known parameters. Developed and verified mathematical tools were used for analysis of dynamic responses of the real object: a laboratory (physical) model of the transmission tower. For the considered laboratory model it was possible to simulate damages of individual truss elements and observe changes in system dynamic characteristics. Results of the carried out research proved that the first natural frequency and damping factor change in the observable extent as a result of damage presence.

Pages : 39-48

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Abstract (EN)
The paper deals with the structural design and strength calculations using analytical and numerical method for a hydraulic arm to be mounted on the light truck chassis. The whole arm is made up of three parts of the steel structure, namely a cranking arm, a lifting arm, and a slewing column. We approached to strength calculations of these three parts of the hydraulic arm individually, using two methods to verify the safety of the designed structure. Loading of the arm will be induced by a burden of the total maximum weight = 300 kg.

Pages : 49-58

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Abstract (EN)
The aim of the paper is to detect and identify diagnostic symptoms based on parametric modeling with the use of system identification methods in the scope of monitoring techniques intended for rotating machinery under transient operational conditions. The development effort should focus on early warning methods in order to increase detectability and performance of machines operation. The diagnostic symptoms may prove to be a powerful tool for the decision support systems based on easier interpretable parameters of a parametric model. The paper discusses the experimental results obtained with the use of a laboratory test rig as well as data from conducted numerical simulations.

Pages : 59-64

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Abstract (EN)
The article presents an algorithm of diagnosing damages to the exhaust valve of the combustion engine. The process of obtaining a symptom as a difference spectrum takes into account time selection, which allows to reduce significantly the calculations necessary to obtain a measure of malfunction. As a result, we obtain a simple measure not requiring special conditions of object work and insensitive to simultaneously occurring valve clearance which is inappropriately set. Thus, we obtain a measure easy to use in diagnostics in real time.

Pages : 65-72

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Abstract (EN)
Crossing signaling systems used for securing the intersection traffic at the level of roads with railways are mostly triggered by rail vehicles coming towards them using sensors working in the impact zones. Modern crossing signaling detection devices due to their unification and savings in production are used not only in crossing signaling but also in many areas of the railway traffic control like, e.g. block signaling or station system. Modern sensors detect the route direction of the rail vehicles, they are much more resistant to lightning and overvoltage when compared to their predecessors, they are also resistant to winter road salinisation and also have much lower maintenance costs during their whole lifecycle.

Jarosław DYK
Pages : 73-78

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Abstract (EN)
In the paper the possibility of the direct application of forcing computed function based on the elementary model of the diesel engine regarding issues of the rattle vibrations in modelling of gears was introduced. In this way the simulated indicator diagrams were created. After that, build diagrams were used to calculate tangential forces and torques operating in the drive system. Considering only the torsional vibrations, these calculated values of torques can be introduced as the forcing that are acting on gears inside of the gearbox. The presented in the article different models enable us to diagnose and analyse the neutral gear rattle. The forcing of the diesel engine introduced at the low range of rotation speeds is one of the most important parameters which may cause, within the clearance, the creation of the phenomenon of a lack of contact of the regular meshing of teeth, and, as a consequence vibrations and the difficult acoustic effects connected with rattle.

Pages : 79-84

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Abstract (EN)

The article presents the model of the crankshaft taking into account the coupling of bending and torsional vibrations. In engineering practice the simplification which is omitting this phenomenon is commonly used. Authors using more complicated model show the influence of bending torsional coupling on the frequency structure of the crank system.At the beginning of the article the problem of vibrations in combustion engine is generally discussed. Then there is presented the analysis of forces distribution in a crank system with the assumption that there is no friction in bearing nodes. Further chapters present two approaches to modeling torsional and bending vibrations in crank systems and indicate the application area of the proposed methodology. In the last but one chapter there were discussed the results of numerical simulations of the proposed model of the crank system. The whole was summarized with synthetic conclusions and plans regarding further research.

Pages : 85-92

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Abstract (EN)
The paper deals with the proposal of new maintenance system on a semi-trailer combination. Analysis of wear and damage of air brake system components used on the semi-trailer combination based on real experience from practice and creation of the FMEA analysis of the system using software support are presented.
The need for continuous improvement of product quality, reliability and safety arises from product specifications, government regulatory requirements, agency recommendations, legal implications and above all a company’s desire to improve its market position and customer satisfaction.  These issues require product manufacturers to perform risk analyses that identify and minimize part/system failures throughout the product‘s life cycle. The FMEA methodology is one of the risk analysis techniques recommended by international standards. It is a systematic process to identify potential failures to fulfil the intended function, to identify possible failure causes so the causes can be eliminated, and to locate the failure consequences so the consequences can be reduced.

Pages : 93-98

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Abstract (EN)
The paper gives an overview of previous trends in development of silent-running gearboxes and presents solutions enabling vibration and noise reduction. Advantages and disadvantages of these solutions are discussed. In addition, the paper describes a new original gear design which enables reducing gear vibration and noise without changing gear contact conditions.

Jędrzej BLAUT, Tomasz KORBIEL, Wojciech BATKO
Pages : 99-105

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Abstract (EN)
The paper presents application of a non-linear method (energy operator) to monitor the operation of a plain bearing. The possibility of using the energy operator to evaluate the energy of a simulated mechanical system was analysed. Then, an experiment was conducted in the laboratory environment which involved observation of oil vortexes. This allowed to show the possibility of using the energy operator as a descriptor of operating state of a hydrodynamic bearing.