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1

Investigation of the influence of debonding shapes and debonding locations on vibration behavior of sandwich structure

Demircioğlu Ufuk, Çakır Mutlu Tarık

Composites Theory and Practice

|

2024

|

R. 24, nr 1

39--48

EN

Sandwich structures are employed in many different fields including automobile, marine, and aircraft structures. However, debonding may take place at the core-face sheet interface, reducing the stiffness of the structure. Debonding may occur for a variety of reasons, including initial manufacturing faults, changes in service loads, tool drops, and foreign object impacts. It is critical to comprehend how debonding zones impact the vibration of sandwich structures because decreases in the natural frequencies (NF) could lead to a structure vibrating at resonance and lead to structural failure. This paper investigates the influence of debonding shapes and debonding locations on the free-vibration behavior of sandwich structures. Different sandwich structures that have varied debonding shapes at various locations are modeled using COMSOL MULTIPHYSICS. Debonding is modeled by using the CZM model. Validation studies were performed to validate the current study. After the validation study, free vibration analysis of all the sandwich structures was performed and the first six NF were obtained from the simulations. The results show the influence of the debonding shapes and debonding locations on the NF of the sandwich structures. From the results, it was observed that both the debonding shapes and debonding locations significantly change the NF of the sandwich structures. The debonding shapes cause a reduction and an increase depending on the debonding location. It was also revealed that both debonding shapes and debonding locations have a significant effect on the vibration behavior of sandwich structures. Using this method, the debonding shape and location, delamination shape, and location can be predicted using machine learning algorithms. This study includes free vibration analysis of sandwich structures with different debonding shapes and locations, and the results show that natural frequencies change depending on the debonding shapes and locations. This information can be implemented in machine learning for use in the field of damage detection and utilized to predict the shape and location of delamination in sandwich structures.

2

Application of isogeometric approach to dynamics of curved beam

Łasecka-Plura Magdalena, Białasik Jan, Kuczma Mieczysław, Tabrizikahou Alireza

Vibrations in Physical Systems

|

2023

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Vol. 34, nr 1

art. no. 2023117

EN

In the paper dynamics of a free-form Timoshenko curved beam is investigated. The considered problem is solved using isogeometric analysis. Non-uniform rational B-spline (NURBS) basis functions are applied to describe both geometry and displacement field of the considered beam. The Timoshenko beam theory is used to derive the element stiffness and mass matrices. The application of the presented method is shown in numerical examples. The correctness of the presented approach is proved by comparing the obtained results to those available in the literature and calculated by the finite element method. Analysis of convergence is presented for different orders of NURBS basis functions.

3

Research on vibration-based early diagnostic system for excavator motor bearing using 1-D CNN

Yandagsuren Dorjsuren, Kurauchi Tatsuki, Toriya Hisatoshi, Ikeda Hajime, Adachi Tsuyoshi, Kawamura Youhei

Journal of Sustainable Mining

|

2023

|

Vol. 22, iss. 1

65--80

EN

In mining, super-large machines such as rope excavators are used to perform the main mining operations. A rope excavator is equipped with motors that drive mechanisms. Motors are easily damaged as a result of harsh mining conditions. Bearings are important parts in a motor; bearing failure accounts for approximately half of all motor failures. Failure reduces work efficiency and increases maintenance costs. In practice, reactive, preventive, and predictive maintenance are used to minimize failures. Predictive maintenance can prevent failures and is more effective than other maintenance. For effective predictive maintenance, a good diagnosis is required to accurately determine motor-bearing health. In this study, vibration-based diagnosis and a one-dimensional convolutional neural network (1-D CNN) were used to evaluate bearing deterioration levels. The system allows for early diagnosis of bearing failures. Normal and failure-bearing vibrations were measured. Spectral and wavelet analyses were performed to determine the normal and failure vibration features. The measured signals were used to generate new data to represent bearing deterioration in increments of 10%. A reliable diagnosis system was proposed. The proposed system could determine bearing health deterioration at eleven levels with considerable accuracy. Moreover, a new data mixing method was applied.

4

Eksperymentalne badanie agregatów pompowych z uwzględnieniem podatności fundamentów

Katunin Andrzej, Jaroszewicz Jerzy

Dozór Techniczny

|

2023

|

z. 1

9--20

PL

W artykule zaprezentowano wyniki badań analizy drganiowej pompy typu 40B80 w celu identyfikacji przyczyn nadmiernych drgań. Badania polegały na pomiarze i analizie widmowej sygnałów drganiowych w łożyskach silnika i pompy w celu identyfikacji składowych harmonicznych i odpowiadających im częstości. Następnie przeprowadzono analizę numeryczną odpowiedzi częstotliwościowej górnej płyty fundamentu badanego agregatu w celu sprawdzenia wpływu drgań własnych fundamentu na drgania rejestrowane w łożyskach.

5

Fabrication of a test rig for gearbox fault simulation and diagnosis

Dubaish Asaad Abdulhussein, Jaber Alaa Abdulhady

Diagnostyka

|

2023

|

Vol. 24, No. 2

art. no. 2023204

EN

Gearboxes are one of the most important and widely exposed to different types of faults in machines. Therefore, manufacturers and researchers have made significant efforts to develop different fault detection and diagnostic approaches for gearboxes. However, many research foundations, such as universities, are currently working on developing different gearbox test rigs to understand the failure mechanisms in gearboxes. As a result, in this article, a gearbox testing rig was proposed and fabricated to evaluate gear performance under lowspeed working conditions. It describes the primary mechanical apparatus and the measurement tools used during the experimental analysis of a multistage gearbox transmission system. The data-gathering equipment used to acquire the observed vibration data is also discussed. LabVIEW software was used to build a data acquisition platform using an accelerometer and a NI DAQ device. Then different vibration tests were conducted under different operating conditions, when the gearbox was healthy and then faulty, on this test rig, and the gathered vibration data were analyzed based on time domain signal analysis. The preliminary results are promising and open the horizon for simulating different gearbox test scenarios.

6

An integrated study for solving high vibration problem of a deep well turbine pump

El-Gazzar Dalia M.

Diagnostyka

|

2023

|

Vol. 24, No. 2

art. no. 2023209

EN

Mechanical vibrations are a common problem encountered in many machines, especially for vertical turbine pumps. These pumps are generally difficult to stiffen or damp, but the effective diagnosis must begin with an understanding of the underlying vibratory sources. In the present work, a deep well vertical turbine pump experienced extremely high vibrations for a long time although it still being new. It hasn't been in operation for over 6 months. The pump system suffers from extremely high vibration levels relative to the rotational speed (1X motor dominant frequency). An efficient strategy was implemented by using well-conceived techniques. The experimental modal analysis confirmed a presence of a natural frequency. Modifications were carried out to overcome resonance. Finite element analysis was done to determine the reed critical frequencies as a powerful tool to identify and mitigate vibration issues. On-site motor balancing was done to remove vibrations due to the residual imbalance. Results revealed decreasing vibration level by about 66% after solving all problems.

7

Aproksymacja i ekstrapolacja drgań maszyny indukcyjnej w funkcji liczby zwartych zwojów uzwojenia stojana

Pietrowski Wojciech, Górny Konrad, Marczak Mikołaj

Automatyka, Elektryka, Zakłócenia

|

2023

|

Vol. 14, nr 1(51)

28--44

PL

Celem badań było rozszerzenie możliwości monitorowania i diagnostyki maszyn elektrycznych na podstawie drgań maszyny. Autorzy zaproponowali bezinwazyjną metodę diagnostyczną uwzględniającą wielofazowe zwarcia międzyzwojowe w uzwojeniu stojana. W pracy przedstawiono i omówiono zarówno proces pozyskiwania sygnału diagnostycznego jak również opracowaną metodę diagnostyczną. Opracowaną metodę zweryfikowano.

EN

The aim of the research was to extend the possibilities of monitoring and vibration diagnostics of electric machines. The authors proposed a non-invasive diagnostic method taking in to account multi-phase inter-turn short-circuits in stator winding. The process of acquiring of the diagnostic signal and proposed diagnostic method have been presented, concluded and discussed. Moreover, the developed method was verified and the error of the proposed method was calculated.

8

Approximation and Extrapolation of Vibrations in Induction Machines as a Function of Numbers of Short-circuited Turns in Stator Winding

Pietrowski Wojciech, Górny Konrad, Marczak Mikołaj

Automatyka, Elektryka, Zakłócenia

|

2023

|

Vol. 14, nr 1(51)

10--26

EN

The aim of the research was to extend the possibilities of monitoring and vibration diagnostics of electric machines. The authors proposed a non-invasive diagnostic method taking in to account multi-phase inter-turn short-circuits in stator winding. The process of acquiring of the diagnostic signal and proposed diagnostic method have been presented, concluded and discussed. Moreover, the developed method was verified and the error of the proposed method was calculated.

PL

Celem badań było rozszerzenie możliwości monitorowania i diagnostyki maszyn elektrycznych na podstawie drgań maszyny. Autorzy zaproponowali bezinwazyjną metodę diagnostyczną uwzględniającą wielofazowe zwarcia międzyzwojowe w uzwojeniu stojana. W pracy przedstawiono i omówiono zarówno proces pozyskiwania sygnału diagnostycznego jak również opracowaną metodę diagnostyczną. Opracowaną metodę zweryfikowano.

9

Finite element model updating of steel-concrete composite bridge: A study case of the Ruri bridge in Vietnam

Nguyen Duc Cong, Salamak Marek, Katunin Andrzej, Gerges Michael, Abdel-Maguid Mohamed

Archives of Civil Engineering

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2023

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Vol. 69, nr 3

425--443

EN

The study presents the finite element (FE) model update of the existing simple-spans steel-concrete composite bridge structure using a particle swarm optimisation (PSO) and genetic algorithm (GA) approaches. The Wireless Structural Testing System (STS-WiFi) of Bridge Diagnostic, Inc. from the USA, implemented various types of sensors including: LVDT displacement sensors, intelligent strain transducers, and accelerometers that the static and dynamic historical behaviors of the bridge structure have been recorded in the field testing. One part of all field data sets has been used to calibrate the cross-sectional stiffness properties of steel girders and material of steel beams and concrete deck in the structural members including 16 master and slave variables, and that the PSO and GA optimisation methods in the MATLAB software have been developed with the new innovative tools to interface with the analytical results of the FE model in the ANSYS APDL software automatically. The vibration analysis from the dynamic responses of the structure have been conducted to extract four natural frequencies from experimental data that have been compared with the numerical natural frequencies in the FE model of the bridge through the minimum objective function of percent error to be less than 10%. In order to identify the experimental mode shapes of the structure more accurately and reliably, the discrete-time state-space model using the subspace method (N4SID) and fast Fourier transform (FFT) in MATLAB software have been applied to determine the experimental natural frequencies in which were compared with the computed natural frequencies. The main goal of the innovative approach is to determine the representative FE model of the actual bridge in which it is applied to various truck load configurations according to bridge design codes and standards. The improved methods in this document have been successfully applied to the Vietnamese steel-concrete composite bridge in which the load rating factors (RF) of the AASHTO design standards have been calculated to predict load limits, so the final updated FE model of the existing bridge is well rated with all RF values greater than 1.0. The presented approaches show great performance and the potential to implement them in industrial conditions.

10

Vibration analysis of variable thickness functionally graded toroidal shell segments

Vuong Pham Minh, Duc Nguyen Dinh

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 3

art. no. e207, 2023

EN

In this paper, for the first time, the nonlinear vibration response of toroidal shell segments with varying thickness subjected to external pressure is investigated analytically using Reddy’s third-order shear deformation shell theory. The variable thickness shells are made of functionally graded material (FGM) that is created from ceramic and metal constituents. The material properties of FGM shells are assumed to be gradually graded in the thickness direction according to a simple power-law distribution in terms of volume fractions of constituents. Equations of motion of variable thickness FGM toroidal shell segments are established based on Reddy’s third-order shear deformation shell theory with von Kármán nonlinearity. The Galerkin method and the Runge–Kutta method are used to solve the governing system of partial differential equations of motion, and then the nonlinear vibration response of variable thickness FGM toroidal shell segment is analyzed. A numerical analysis is also performed to show the effects of material and geometrical parameters on the nonlinear vibration response of variable thickness FGM toroidal shell segments.

11

Thermoelastic vibration characteristics of asymmetric annular porous reinforced with nano-fillers microplates embedded in an elastic medium: CNTs Vs. GNPs

Arshid Ehsan, Amir Saeed, Loghman Abbas

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 2

art. no. e100, 2023

EN

Due to the vast usage of metal foam structures in branches of science, reinforcing them with nano-fillers makes them more convenient. Hence, in the current study, vibration characteristics of functionally graded porous nanocomposite (FGPN) annular microplates are taken into consideration. Two kinds of nano-fillers, namely Carbon nanotubes (CNTs) and Graphene nanoplatelets (GNPs), are selected as the reinforcements to analyze and compare their effect on the microstructure’s vibrational response. The mentioned nano-fillers are dispersed according to four patterns which affect various mechanical properties of the structure. Similarly, based on given functions which are called porosity distributions, pores are placed in thickness course of the microstructure. Then, its properties are determined via employing Halpin-Tsai and extended rule of mixture micromechanics models. Using the first-order shear deformation theory (FSDT), modified couple stress theory (MCST), and Hamilton’s principle for dynamic systems, governing motion equations and related boundary conditions are derived in asymmetric state, and then, they are solved, and natural frequencies and corresponding mode shapes are extracted with the help of generalized differential quadrature method (GDQM). By validating the results in simpler conditions, effects of the most important parameters are examined. It is found that GNPs are more effective in reinforcing the structure than CNTs. Also, about 15~18 percent reduction in frequencies is seen by increasing the porosity up to seventy percent.

12

Vibration analysis and modelling of light-weight robot arms

Leniowski Ryszard, Wroński Michał

Vibrations in Physical Systems

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2022

|

Vol. 33, nr 2

art. no. 2022220

EN

Lightweight robots (LWR) are a new generation of devices intended to be used not only for industrial tasks but also to perform actions in the human environment. This work presents an analysis of selected basic problems related to the vibration properties of light-weight robot arms. The study of vibration is based on the analysis of the root locus on the plane of complex variables. It turns out that their distribution is non-stationary and depends on the parameters of the model (arm geometry, material parameters), but also depends on the type of realised motion, which is not so obvious. Depending on the manoeuvres conducted (acceleration / deceleration), the system may lose (or increase) its oscillating properties at higher frequencies, as well as introduce a structural (measurable) delay. Recognition of the discussed properties along with their modelling is an important element of the design process of the control system of modern, light-weight robots.

13

Improving transportation safety of injured persons by taking into account the biomechanical characteristics of the human body

Gogiashvili Phridon, Lekveishvili Revaz, LekveishvilI Gocha

Transport Problems

|

2021

|

T. 16, z. 4

107--119

EN

Ambulance vehicles play a vital role in sustaining the life of injured persons and should a provide safe transportation route to the medical institution. Transportation of injured patients in severe/critical conditions should be carried out with high caution, as there is no guarantee that patients’ health will not be harmed. The goal of this study is to minimize exposure to the external factors such as random shocks, sharp jumps, vibrations caused by irregular roads, speed breakers, weather, etc., that could influence the tasking ability of the medical team and further threaten the life of the already injured patient. This topic has not been widely researched and still requires implementation of novel standards that should improve the safety of the patient. This article aims to define the biomechanics of cabin occupant safety, introduce ways of collecting live data and develop new mechanisms that would allow safer transportation of patients without any meaningful health deterioration causing by the above-mentioned external factors. This study will identify safety hazards in the ambulance environment and determine the effectiveness of suggested countermeasures to mitigate any further injury or deterioration of the patient’s health.

14

Predictive maintenance techniques for wear reducing and elimination of equipment failures in hydrostatic drive systems

Marinescu Alexandru Daniel, Popescu Teodor Costinel, Nieśpiałowski Krzysztof, Popescu Ana-Maria Carla

Mining Machines

|

2021

|

no. 1

36--45

EN

Maintenance is a very important activity, which is necessary for the good operation of any technical system, even for the hydraulic drive systems. The predictive maintenance evaluates the state of technical performances of a system, by identifying the wear and thus avoiding the failures of the equipment. Using three methods of the predictive maintenance, namely infrared thermography, vibration analysis and oil analysis, the authors present their results of an experimental research on hydraulic pumps. The authors obtained thermograms, vibration spectra and diagrams of the oil contaminants which helped them indicate the proper or the malfunction of the studied pumps. Although they were only made on pumps, their investigations highlight the need of widely implementation of these modern and efficient methods in the industrial activities for the quick monitoring of the hydraulic machinery and equipment wear, before their failure occurs. Obviously, the goal is to have strong maintenance instruments in hydraulic drive systems diagnosis.

PL

Konserwacja to bardzo ważna czynność, niezbędna do prawidłowego działania każdego systemu technicznego, nawet hydraulicznych układów napędowych. Konserwacja predykcyjna ocenia stan wydajności technicznej systemu poprzez identyfikację zużycia i unikanie w ten sposób awarii urządzeń. Wykorzystując trzy nowoczesne metody konserwacji predykcyjnej, tj. termografię w podczerwieni, analizę drgań i analizę oleju, autorzy przedstawiają wyniki badań eksperymentalnych hydraulicznych pomp. Autorzy uzyskali termogramy, widma drgań i diagramy zanieczyszczeń olejowych, które pomogły wskazać prawidłową lub nieprawidłową pracę badanych pomp. Chociaż zostały wykonane tylko na pompach, ich badania podkreślają potrzebę szerokiego wdrażania tych nowoczesnych i efektywnych metod w działalności przemysłowej do szybkiego monitorowania zużycia maszyn i urządzeń hydraulicznych, zanim dojdzie do ich awarii. Oczywiście celem jest posiadanie mocnych narzędzi konserwacyjnych w diagnostyce hydraulicznych układów napędowych.

15

Tricopter vibration analysis

Popardovský Vladimír, Ferenčák Marek, Kriš Tomáš, Tomaštík Miroslav, Novotný Lukáš

Diagnostyka

|

2021

|

Vol. 22, No. 3

67--72

EN

Unmanned Aerial Vehicle (UAV) is exposed to various types of stress during flight. One of the most significant negative influences is the vibrations produced by the rotating parts. If we assume a UAV of the multicopter type, it is a stress of the whole structure by vibrations produced by propulsion units, which are placed on symmetrically distributed arms. The propulsion unit consists of an electric-propeller assembly, with the propeller being the largest source of vibration. This is due to the uneven distribution of the mass with respect to its axis of rotation. In addition to the propeller, the rotating part is also the electric motor itself, although the electric motor contributes much less to the total vibrations than the propeller. For this reason, it is necessary to balance the propeller first statically and then dynamically balance the entire drive unit (engine + propeller). Our work is focused on vibration diagnostics of an experimental tricopter in order to optimize the power units - to produce the smallest possible vibrations.

16

Optimized multi layer perceptron artificial neural network based fault diagnosis of induction motor using vibration signals

Khoualdia Tarek, Lakehal Abdelaziz, Chelli Zoubir, Khoualdia Kais, Nessaib Karim

Diagnostyka

|

2021

|

Vol. 22, No. 1

65--74

EN

Installations and the detection of their faults has become a major challenge. In order to develop a reliable approach for monitoring and diagnosis faults of these components, a test rig was mounted. In this article, a Multi Layer Perceptron (MLP) Artificial Neural Network (ANN) has been structured and optimized for online monitoring of induction motors. The input layer of our ANN used eight indicators calculated from the collected time signals and which represent the different states of the motor (Healthy, broken rotor bars, bearing fault and Misalignment) and the output layer used a codified matrix. However, based on L27 Taguchi design, the architecture for the hidden layers of our network is chosen, with the use of the LevenbergMarquardt learning algorithm. Garson's algorithm and connection weight approach showed that there's a great sensitivity of the crest factor, the kurtosis and the variance on the effectiveness of our diagnostic system. Consequently, the obtained results are capable of detecting faults in the induction motor under different operating conditions.

17

Vibration and stability analyses of functionally graded beams

Kılıç Burak, Özdemir Özge

Archive of Mechanical Engineering

|

2021

|

LXVIII, nr 1

93--113

EN

Design considerations, material properties and dynamic properties of engineering applications, rotating components, turbine blades, helicopter blades, etc., have significante ffects on system efficiency. Structures made of functionally graded materials have recently begun to take place in such engineering applications, resulting from the development of composite material technology. In this study, vibration and buckling characteristics of axially functionally graded beams whose material properties change along the beam length is analyzed. Beam structural formulations and functionally graded material formulations are obtained for the Classical and the First Order Shear Deformation Theories. Finite element models are derived to carry out the vibratory and stability characteristic analyses. Effects of several parameters, i.e., rotational speed, hub radius, material properties, power law index parameter and boundary conditions are investigated and are displayed in several figures and tables. The calculated results are compared with the ones in open literature and very good agreement is observed.

18

Vibration analysis of a turbocharger with an additively manufactured compressor wheel

Andrearczyk Artur, Bagiński Paweł

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2020

|

z. 107

05--17

EN

This article presents the vibration analysis of a turbocharger, whose compression wheel was manufactured using a high-precision additive manufacturing technology. Currently, there are advance studies around the world for the development of parts of innovative fluid-flow machines using additive manufacturing techniques. The experimental research was carried out under conditions of reduced flow temperatures. The tests and the analysis were performed on a wheel manufactured using a 3D printing technology and on a conventionally used aluminium wheel. Apart from an FFT analysis of the vibration signal during machine operation, a machine run-up test was conducted (up to a speed of 105,000 rpm). The results showed the positive impact of the use of a plastic wheel on the dynamics of the system at a certain speed range, which might contribute to the development of a new method to optimise the geometry of flow systems in small high-speed turbomachines. A modified automotive turbocharger was subjected to experiments on a test stand.

19

Vibration analysis of functionally graded tapered rotor shaft system

Elhannani Abdelhak, Refassi Kaddour, Elmeiche Abbes, Bouamama Mohamed

Mechanics and Mechanical Engineering

|

2019

|

Vol. 23, nr 1

241--245

EN

This investigation deals with the vibration analysis of a rotating tapered shaft in Functionally Graded Material (FGM). The dynamic system is modeled using the Timoshenko beam theory (FSDBT) with consideration of gyroscopic effect and rotary inertia. The equations of motion are expressed by the hierarchical finite element method based on bi-articulated boundary conditions. The material properties are continuously varied in the thickness direction of a hollow shaft according to the exponential law function (E-FGM). The presented model is validated by comparing the numerical results found with the available literature. Various analyses are carried out to determine the influence of taper angle and material distribution of the two extreme materials on the dynamic behavior of FGM conical rotors system.

20

Vibration analysis of Kenyir Dam power station structure using a real scale 3D model

Arbain Azizi, Ahmad Mazlan Ahmad Zhafran, Zawawi Mohd Hafiz, Mohd Radzi Mohd Rashid

Civil and Environmental Engineering Reports

|

2019

|

Vol. 29, no. 3

48--59

EN

In this paper, the vibration analysis in terms of modal and harmonic responses are investigated for the power station structure of Kenyir Dam in Terengganu, Malaysia. Modal analysis is carried out to provide the dynamic characteristics of the power station which includes the natural frequencies and mode shapes. Meanwhile, the harmonic response analysis is performed by applying the force to the structure to obtain the Frequency Response Function (FRF) in certain range of frequencies. A real scale threedimensional (3D) model of the Kenyir Dam power station is constructed using Solid Works software and imported to ANSYS software for the Finite Element (FE) analysis. A proper boundary condition is taken into consideration to demonstrate the real behaviour of the power station structure. From the results, six most significant natural frequencies and mode shapes including the FRF in all three axes are selected. The highest natural frequency value occurred at 5.4 Hz with the maximum deflection of 0.90361 m in the z axis direction. This value is important in order to verify whether the structure can overcome the resonance phenomenon from the external disturbance forces in the future.