Wyniki wyszukiwania - Biblioteka Nauki

1

Profesor Zbyszko Stojek - okres pracy w Rzeszowie

100%

Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2008

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tom z. 74 [258]

XI-XXIII

2

Identyfikacja sztywności w układach belkowych na podstawie zmian parametrów modalnych wywołanych dodatkową masą

63%

Borowiec A. , Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2005

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tom z. 65 [222]

19--24

EN

This paper presents the application of Artificial Neural Networks (ANN) in the identification of damage in simple engineering structures. The application of ANNs expands the nondestructive damage identification method using an additional parameter introduced to the structure. The input vector of the ANNs consists of the dynamic responses of a structure with additional mass. The output vector is composed of the position of damage and the extent of damage.

3

Identyfikacja uszkodzenia w paśmie aluminium z wykorzystaniem miękkich metod obliczeniowych

63%

Jurek M. , Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2008

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tom z. 74 [258]

127-134

EN

This paper presents an application of non-destructive damage detection method based on structural wave propagation phenomenon. A set of laboratory experiments on aluminium strip was carried out. Several failure cases were introduce into the laboratory model. Elastic wave was actuated and received by piezoelements. Recorded signals were processed using wavelet analysis. Obtained signal parameters were used as an input vector of artificial neural networks. Several network architectures were tested.

4

Ocena stanu konstrukcji belkowych na podstawie zmiany parametrów modalnych wywołanych dodatkową masą

63%

Borowiec A. , Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2008

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tom z. 74 [258]

9-16

EN

This paper presents the application of the nondestructive damage identification method using an additional parameter introduced to the structure. In this method the damage is identified on the basis of the variations of dynamie parameters without knowledge of the initial values of undamaged structures. In the presented numerical examples, method are applied for the analysis of the dynamic response of cantilever beam for identification position of damage and the extent of damage. The assessment of the state of a structure relies on the comparison of the structure eigen-frequencies obtained from the systems with additional masses placed in different nodes.

5

Wykrywanie uszkodzeń konstrukcji z wykorzystaniem fal sprężystych oraz sztucznych sieci neuronowych

63%

Nazarko P. , Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2008

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tom z. 74 [258]

271-282

EN

Examination of structures integrity and failures detection are nowadays of great interest for both civil infrastructure and industry systems. This paper presents Structural Health Monitoring (SHM) technique that was tested on several laboratory models and utilizes elastic wave propagation phenomenon. Furthermore, it describes signals feature extraction procedure by using Principal Component Analysis (PCA). Artificial Neural Networks (ANNs) and statistical learning theory are used to determine and classify structure's damages. The results show that data reduction using PCA, followed by implementation of ANNs patterns recognition, provide a good indication of failure occurrence and they may be used for SHM.

6

Identyfikacja obciążenia uplastyczniającego w ramie

63%

Miller B. , Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2005

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tom z. 65 [222]

297-302

EN

Possible yielding of the cross-section of a structure, which may arise as a result of external actions or the (micro)defects, might significantly decrease the safety margin of the considered structure. Since the cross-section yielding affects the structure stiffness, the dynamic characteristics (eigenvalues and eigenvectors) might be significantly different then the ones of the original structure. The measurement of the changes of the dynamic parameters may provide the information necessary to identify the load causing the yielding of the cross-section and further the yielding index (which may be calculated when the load causing the yielding is know) enables the evaluation of the structure safety margin. This paper presents some new results of Artificial Neural Networks (ANN) [2] application in the identification of the load causing partial yielding of simple frames.

7

Lokalizacja dodatkowej masy w układzie drgającej płyty

63%

Piątkowski G. , Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2005

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tom z. 65 [222]

311-318

EN

This paper presents the application of Artificial Neural Networks [1,2] for solution of an inverse problem. Based on the dynamic characteristics of a plate, the neural identification of parameters of additional mass have been performed. Emphasis was placed on the effective preparation of learning data, which were obtained by experiment.

8

Badania dynamiczne odbieraka prądu lekkiego pojazdu szynowego

63%

Borowiec A. , Ziemiański L.

Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture

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2017

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tom z. 64, nr 2/I

257--270

PL

Badania dynamiczne odbieraka prądu pojazdu szynowego przeprowadzono w celu określenia parametrów modalnych projektowanego rozwiązania. Przedmiotem badań był odbierak prądu dedykowany do lekkich pojazdów szynowych (tramwaj, kolej miejska, metro) o oznaczeniu 120ECI. W celu weryfikacji modelu modalnego podczas badań porównano wyniki analiz modalnych dla różnych sposobów wymuszania drgań (losowo, impulsowo). Przeprowadzono pomiary dla pięciu położeń ślizgacza pantografu w zakresie jego pracy.

EN

Dynamic testing of the rail vehicle current collector (pantograph) was conducted to determine the modal parameters of the proposed solution. The subject of the study was a current receiver dedicated to light rail vehicles marked 120ECI. In order to verify the modal model, the results of the modal analyzes for different vibration induction methods (random, pulsed) were compared. Measures were taken for the five positions of the collector head in its working range.

9

Evaluation of the efficiency of an noise barrier along the railway line Rzeszow-Medyka

63%

Pereta K. , Ziemiański L.

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2015

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tom z. 62, nr 4

369--378

EN

The noise is generated by trains due to the operation of the engine, the wheels rolling on rails and train aerodynamics. In order to reduce rail noise one can distinguish passive and active measures aimed at reducing noise. The passive noise protection measures include railway noise barriers and insulated windows. In this article the efficiency of noise barriers along the railway line Kraków - Medyka in Debica has been discussed. The test screen with a length of about 590m and a height of 3m located on the embankment height of 4m protects single-family housing residents against excessive influence of railway noise. The efficiency of the test screen depending on the type of the train and the track it is moving on is in the range between 4 - 17 dB.

PL

Hałas generowany przez pociągi pochodzi od pracującego silnika, toczących się kół oraz zjawisk aerodynamicznych. W celu ograniczenia hałasu kolejowego stosować możemy bierne i czynne środki redukujące hałas. Do zabezpieczeń pasywnych możemy zaliczyć ekrany akustyczne oraz okna o podwyższonym standardzie akustycznym (okna o lepszej izolacyjności akustycznej). W niniejszym artykule omówiono zabezpieczenia przed hałasem kolejowym w postaci ekranów akustycznych. Omawiany ekran zlokalizowany jest wzdłuż linii kolejowej Rzeszów – Medyka w miejscowości Dębica. Omawiany ekran o długości około 590m i wysokości 3m znajduje się na nasypie o wysokości 4m. Zadaniem badanego ekranu jest ochrona mieszkańców domów jednorodzinnych przed nadmiernym hałasem kolejowym. Skuteczność badanego ekranu w zależności od rodzaju pociągu i nr toru, po którym się poruszał mieści się w przedziale od 4 dB do 17 dB.

10

Drgania parametryczne układu bryła - wibroizolatory

63%

Stojek Z. , Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2002

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tom z. 60 [197]

561-568

11

Dostrajanie matematycznych modeli konstrukcji inżynierskich z zastosowaniem sztucznych sieci neuronowych

63%

Miller B. , Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2002

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tom z. 60 [197]

449-456

EN

This paper presents some examples of updating of computational models of engineering structures. As a tool for model updating artificial neural networks are used. The updated models are verified by the comparison of dynamic parameters of modeled structures obtained from numerical simulations and experimental measurements done on laboratory. The developed updating method is used also in identification of structure defects.

12

Identyfikacja położenia otworu kołowego w tarczy przy użyciu sieci neuronowych

63%

Piątkowski G. , Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2002

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tom z. 60 [197]

473-480

EN

The numerical tests have been carried out for rectangular plates with internal defect in a form of a circular hole. The wide variety of hole's positions and diameters were checked. Two identification procedures are presented. Neural network analysis of the calculated eigenfrequencies is the first way to obtain the hole's center coordinates and hole's diameter. The second one is based on analysis of a structural response to a harmonic excitation. The multi-layer feed forward backpropagation neural networks with one hidden layer have been applied. The two approaches of network's architectures have been applied; standard and cascade.

13

Zastosowanie testów statycznych i dynamicznych do oceny węzłów podatnych

63%

Łakota W. , Ziemiański L.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2002

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tom z. 60 [197]

387-396

EN

The paper explores the potential of using artificial neural networks, for assessment of flexible steel joints, based on dynamic data. The study was carried out on a three types of steel joints, for which natural frequencies were recorded from dynamic tests. The results of this work showed that a neural network trained with experimental dynamic data was capable for detecting actual state of the joint.

14

The identification of the load causing partial yielding on the basis of the dynamie characteristics

63%

Miller B. , Ziemiański L.

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tom Vol. 13, No. 4

627-631

EN

Possible yielding of the cross-section of a structure, which may arise as a result of external actions or the (micro)defects, might significantly decrease the safety margin of the considered structure [2]. Since the cross-section yielding affects the structure stiffness, the dynamie characteristics (eigenvalues and eigen-vectors) might be significantly different then the ones of the original structure. The measurement of the changes of the dynamie parameters may provide the information necessary to identify the load causing the yielding of the cross-section and further the yielding index (which may be calculated when the load causing the yielding is know) enables the evaluation of the structure safety margin. This paper presents the application of Artificial Neural Networks (ANN) [4, 9] in the identification of the load casing partial yielding of simply-supported beam and one- or two-column frames.

15

Application of artificial neural networks in the damage identification of structural elements

63%

Nazarko P. , Ziemiański L.

Computer Assisted Mechanics and Engineering Sciences

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2011

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tom Vol. 18, no. 3

175-189

EN

The paper presents a structure test system developed for monitoring structural health, and discusses the results of laboratory experiments conducted on notched strip specimens made of various materials (aluminium, steel, Plexiglas). The system takes advantage of elastic wave signals actuated and sensed by a surface-mounted piezoelectric transducers. The structure responses recorded are then subjected to a procedure of signal processing and feature’s extraction, which includes digital filters, wavelets decomposition, Principal Components Analysis (PCA), Fast Fourier Transformation (FFT), etc. A pattern database defined was used to train artificial neural networks and to establish a structure diagnosis system. As a consequence, two levels of damage identification problem were performed: novelty detection and damage evaluation. The system’s accuracy and reliability were veri?ed on the basis of experimental data. The results obtained have proved that the system can be used for the analysis of simple as well as complex signals of elastic waves and it can operate as an automatic Structure Health Monitoring system.

16

Zastosowanie sztucznych sieci neuronowych do identyfikacji uszkodzenia w belkach – badania numeryczne i doświadczalne

63%

Borowiec A. , Ziemiański L.

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tom R. 109, z. 8-M

3--13

PL

W pracy przedstawiono zastosowanie sztucznych sieci neuronowych (SSN) do identyfikacji uszkodzenia (położenie, wielkość) w belkach laboratoryjnych. Ocena uszkodzenia belek polega na analizie zmian częstotliwości rezonansowych wywołanych dodatkową zmieniającą położenie masą. Metoda nie wymaga znajomości parametrów modalnych belki nieuszkodzonej.

EN

This paper presents the application of Artificial Neural Networks (ANN) in the identification of damage (location, extent) in simple laboratory beam structure. The assessment of the state of a beams relies on the comparison of the structure eigenfrequencies obtained from the systems with additional masses placed in different nodes without knowledge of the natural frequencies of undamaged structures.

17

57. Konferencja Naukowa Komitetu Inżynierii Lądowej i Wodnej PAN oraz Komitetu Nauki PZITB RZESZÓW-KRYNICA 2011

63%

Ziemiański L. , Konkol J.

Nowoczesne Budownictwo Inżynieryjne

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2011

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tom Nr 6

24-25

PL

Tradycyjnie w Krynicy Zdroju, w dniach 18.22 września 2011 r., odbyła się 57. Konferencja Naukowa Komitetu Inżynierii Lądowej i Wodnej PAN oraz Komitetu Nauki PZITB KRYNICA 2011. Organizację tegorocznej konferencji powierzono Wydziałowi Budownictwa i Inżynierii Środowiska Politechniki Rzeszowskiej.

18

Wykorzystanie zmian w charakterystykach dynamicznych do lokalizacji obciążenia wywołującego uplastycznienie belki

63%

Miller B. , Ziemiański L.

|

2010

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tom R. 107, z. 3-B

143-151

PL

W artykule przedstawiono lokalizację obciążenia wywołującego uplastycznienie w konstrukcji belkowej na podstawie zmian charakterystyk dynamicznych. Porównując charakterystyki dynamiczne konstrukcji wyjściowej z pomierzonymi na konstrukcji obciążonej dodatkowym, znanym obciążeniem kontrolnym, otrzymano informacje pozwalające zlokalizować obciążenie.

EN

The paper presents the localization of the load casing yielding in a beam structure on the basis of changes of dynamic parameters. The comparison of dynamic characteristics of investigated structure and the structure loaded with an additional, known load gives the information necessary to the identification of the load casing yielding.

19

Neurocomputing in the analysis of selected inverse problems of mechanics of structures and materials

63%

Waszczyszyn Z. , Ziemiański L.

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tom Vol. 13, No. 1

125-159

EN

The main goal of the paper is to show great potential of Artificial Neural Networks (ANNs) as a new tool in the identification analysis of various problems in mechanics of structures and materials. The basics of ANNs are briefly written focusing on the Back Propagation Neural Networks (BPNNs) and their features and possibilities in the analysis of inverse problems. Two groups of problems are analyzed: I) BPNNs are used in five problems as independent tools for the parametric identification and implicit modelling of physical relations, II) BPNNs are parts or procedures in three hybrid FEM/ANN systems or programs. Using measured eigenfrequencies the following problems are discussed: 1) identification of damage parameters of a steel beam, 2) attachment of an additional mass to increase the accuracy of prediction of damage parameters in a beam, 3) identification of location an additional mass attached to a steel plate. Implicit simulation of physical relations is discussed on two problems: 1) concrete fatigue durability of concrete as a function of concrete strength and characteristics of fatigue cycles (besides BPNN also the Fuzzy Weight NN was applied), 2) soil-structure interaction of displacement response spectra of a real building subjected to paraseismic excitations (besides BPNN the application of Kalman filtering is discussed for the NN learning). The following problems of Group II are investigated: 1) using BPNN in the hybrid Monte Carlo method for the reliability analysis of a steel girder, 2) application of BPNN to the calibration of control parameters in the updating of a FE program for dynamic analysis of a plane frame, 3) on-line methods for the NN constitutive model formulation basing on measurements of structural displacements.

20

Novelty detection based on elastic wave signals measured by different techniques

63%

Nazarko P. , Ziemiański L.

Computer Assisted Methods in Engineering and Science

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2012

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tom Vol. 19, no. 4

317-330

EN

The paper discusses the results of laboratory experiments i n which three independent measurement techniques were compared: a digital oscilloscope, phased array acquisition system, a laser vibrometer 3D. These techniques take advantage of elastic wave signals actuated and sensed by a surface-mounted piezoelectric transducers as well as non-contact measurements. In these e xperiments two samples of aluminum strips were investigated while the damage was modeled by drilling a hole. The structure responses recorded were then subjected to a procedure of signal processing, and features’ extraction was done by PrincipalComponents Analysis. A pattern database defined was used to train artificial neural networks for the purpose of damage detection.