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1

Comparative analysis of motor current signature analysis and vibration monitoring for bearing fault diagnosis using Wavelet-Kurtogram method

Khodja Mohamed-El-Amine, Aimer Ameur Fethi, Boudinar Ahmed Hamida

Przegląd Elektrotechniczny

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2026

|

R. 102, nr 3

194--201

EN

Vibration analysis and Motor Current Signature Analysis (MCSA) are widely used in induction motor fault diagnosis. However, despite the numerous studies devoted to these techniques, the diagnosis of rolling-element bearing faults remains a complex challenge, especially in incipient fault diagnosis. To this end, this paper proposes the use of the Wavelet-Kurtogram method in order to compare the reliability of both motor signatures analysis techniques. The Wavelet-Kurtogram method relies on the wavelet transform for the decomposition of the analyzed signal into different frequency sub-bands and uses the kurtosis to determine which band contains most information on the searched fault. Results obtained from experimental tests demonstrate the performance of both signatures in the identification of outer race bearing fault. However, through the use of Wavelet-Kurtogram method the MCSA technique seems to be more relevant since it allows the diagnosis of rotor cage imbalance in addition to the bearing fault.

PL

Analiza drgań i analiza sygnatury prądu silnika (MCSA) są szeroko stosowane w diagnostyce usterek silników indukcyjnych. Jednak pomimo licznych badań poświęconych tym technikom, diagnostyka usterek łożysk tocznych pozostaje złożonym wyzwaniem, szczególnie w początkowej fazie diagnostyki usterek. W tym celu w niniejszym artykule zaproponowano zastosowanie metody falki-kurtogramu w celu porównania niezawodności analizy obu sygnatur silników. Metoda falki-kurtogramu opiera się na transformacji falkowej do rozkładu analizowanego sygnału na różne podpasma częstotliwości i wykorzystuje kurtozę do określenia, które pasmo zawiera najwięcej informacji o poszukiwanej usterce. Uzyskane wyniki badań eksperymentalnych pokazują skuteczność obu sygnatur w identyfikacji usterek bieżni zewnętrznej łożyska. Jednakże, dzięki zastosowaniu metody falki-kurtogramu, technika MCSA wydaje się być bardziej odpowiednia, ponieważ umożliwia diagnozę niewyważenia klatki wirnika, oprócz usterki łożyska.

2

Possibility of using polyurethane materials to reduce vibrations and noise in the working environment

Łakomy Karolina, Małysa Tomasz, Nowacki Krzysztof

Composites Theory and Practice

|

2025

|

R. 25, nr 2

132-143

EN

Noise and vibrations are physical factors, the impact of which on the employee may negatively affect their health. Therefore, it is extremely important to effectively reduce the negative impact of these factors by implementing solutions that reduce the risk. In the article the possibility of using selected porous materials (layer systems) in the frequency range from f = 100 Hz to f = 2500 Hz, is presented. In order to assess the suitability of the application of the developed layer system, tests were carried out to determine the physical sound absorption coefficient (Kundt's tube), as well as to assess the effectiveness of vibration damping by polyurethane materials in the form of a layer system. It was found that the developed layer system can be used to reduce vibrations and noise. The developed layer system was characterized by the desired sound absorption properties αfśr > 0.6, in addition to damping efficiency above 50%, especially in the range of f = 315 Hz - 2500 Hz. The developed layered system took into account the frequency ranges characterized by the highest αf values (f = 1000-2500 Hz) as well as the effectiveness, aimed at a permanent reduction in physical factors (noise, vibrations) in the case of design solutions focused on limiting the negative impact of these factors on employees' health.

3

Vibration characteristics of a sandwich plate with viscoelastic auxetic core and graphene nanoplatelets reinforced skins

Namazinia Nima, Alibeigloo Akbar, Karimiasl Mahsa

Archives of Civil and Mechanical Engineering

|

2025

|

Vol. 25, no. 1

art. no. e49, 2025

EN

The present research aims to examine the free vibrational behavior of a sandwich plate comprising a viscoelastic auxetic core and functionally graded graphene nanoplatelets reinforced composite (FG-GPLRC) face layers, which are rested on a Winkler–Pasternak foundation. The macro-mechanical characteristics of the plate’s skins have been determined utilizing the Halpin–Tsai theory. Additionally, for the core layer, besides the features characterized using Gibson’s model, the Zener model is employed to describe its viscoelastic behavior. The equations of motion for the sandwich plate were derived based on Reddy’s third-order shear deformation theory (TSDT), and they were solved using the Galerkin method. To validate the numerical results of the current study, they have been compared with findings documented in prior ones. Overall, the effects of several parameters such as geometrical parameters, various GPL distribution patterns, boundary conditions, Winkler–Pasternak coefficients, and the volume fractions of GPL have been investigated on the natural frequency and loss factor of the sandwich plate.

4

Vibration analysis of a MacPherson type suspension system

Georgiev Zlatin, Kunchev Lilo

Transport Problems

|

2024

|

T. 19, z. 3

193--202

EN

The road surface disturbs the pneumatic tyre in the contact patch withdifferent frequencies. The disturbing frequency depends on the speed of the vehicle andthe wavelength of the road irregularities. In the current study, the propagation of thevibrations created at the contact patch through the suspension is presented. The oscillationsare transmitted to the car body through the rubber mounts and the support joints. Whenthese vibrations reach body panels (roof and floor panels, windows, etc.), they aretransmitted to the air and, thus, the structure-borne noise in the passenger compartment iscreated. The structure-borne noise defines the vehicle comfort for the frequency range upto 400 Hz. The main task of noise, vibration, and harshness engineers is to avoid couplingbetween tyre and chassis elements’ natural modes, which significantly increases the levelof structural noise in the passenger compartment. The accelerations of the oscillations weremeasured for different points of the suspension and the car body. The measurements weretaken for two sets of tyres (summer and winter) of the same size and mounted on the samerims. The disturbing frequency was in the range of the tyre’s natural modes. The results forthe two sets of tyres were compared. The measurements were taken for different airpressure in them. This comparison shows the effect of the tyre type on the structure-bornepropagation and determines whether increased noise levels are due to the resonance of thetyre or a suspension element. In addition, a finite element analysis (FEA) was conducted.The model points out the exact element responsible for the high levels of vibrations. Thus,the coupling between the tyre and suspension natural modes can be avoided.

5

Assessment of the technical state of mining machinery and devices with the use of diagnostic methods

Biały Witold

Production Engineering Archives

|

2024

|

Vol. 30, Iss. 2

266--272

EN

In this article, one of the possible, effective methods of assessing the technical state of mining machinery and devices has been presented. The article's main goal is to show the possible methods and ways of measuring temperature, oscillations, and vibrations generated during the operation of mining equipment and machines’ gears, which are possible in underground conditions. Devices measuring temperatures without coming into contact with the given object are built based on different types of infrared radiation detectors or matrixes of such detectors. Thermal imaging devices picture the temperature distribution on the entire surface instead of pyrometers, which measure temperatures at a given point. However, vibrations and oscillations generated by the work of gears of devices and machinery have been made using a vibrometer pen and a machine condition tester, after which the obtained measurements were used to diagnose the degradation of individual elements of those machines. Such an assessment of the degradation of individual elements of machines in production conditions has been applied with positive results in one of the mines of the Polish Mining Group (Polska Grupa Górnicza – PGG).

6

Selected Issues of Measurement Methodology in the Context of Assessing the Impact of Vibrations on People in Buildings

Kowalska-Koczwara Alicja, Tatara Tadeusz, Pachla Filip

Inżynieria Mineralna

|

2024

|

Vol. 1, no. 2

art. no. 39

EN

Vibrations transmitted through soil into buildings have the potential to inflict structural damage or accelerate the building's degradation, while also exerting an influence on the occupants' comfort. These oscillations can elicit annoyance among building inhabitants, and in extreme cases, manifest as disturbances in sleep patterns, headaches, and even neuropsychiatric disorders. Particularly concerning are vibrations within the low-frequency spectrum, ranging from 5 to 25 Hz, as this encompasses resonant frequencies of human internal organs. Despite extensive prior research efforts and the stipulations delineated in regulatory standards, the comprehensive understanding of vibrations' impact on individuals within buildings remains elusive, primarily due to the inherently subjective nature of vibrational perception among diverse individuals. Evidenced by recent amendments in national standards and international ISO norms, ongoing adjustments underscore the evolving comprehension of this phenomenon. The article comprehensively elucidates guidelines essential for the precise execution and thorough analysis of measurements about the impact of vibrations on individuals situated within buildings that passively receive such vibrations. These recommendations encapsulate a multifaceted approach, encompassing both the requisite specifications for equipment and instrumentation as well as the judicious selection of measurement locations and the meticulous scrutiny of recorded data. A pivotal facet in the measurement methodology of vibrations' impact on individuals within buildings lies in the discerning selection of measurement point locales. Diverse standards proffer disparate directives in this regard, thereby necessitating a comparative analysis elucidated within the article. Moreover, the article delves into the intricacies of choosing the measurement range and applying corrective filters during analysis, underscoring their significance in ensuring accuracy and reliability. Nonetheless, at the core of the methodology lies the critical determination of vibration duration, an indispensable consideration for comprehensive analysis. Finally, the article addresses a crucial aspect concerning data analysis: the frequency of sampling the recorded signal, which holds profound implications for the fidelity and efficacy of subsequent analyses and interpretations. Through an exhaustive exploration of these facets, the article furnishes invaluable insights into optimizing the methodology for evaluating the impact of vibrations on individuals within built environments.

7

Modal analysis research for prevending bridge construction disasters

Żółtowski Mariusz, Baryłka Adam, Ogrodnik Paweł, Rutkowska Gabriela

Inżynieria Bezpieczeństwa Obiektów Antropogenicznych

|

2024

|

Nr 4

23--34

EN

In this contribution, the author will attempt to demonstrate the potential applicability of frequency-domain estimators in the field of modal analysis. The basics of vibration and modal analysis will be briefly summarised. In modal analysis, it is important to identify a mechanical system with a few inputs and hundreds of outputs. This requires the adaptation of frequency-domain estimators designed to handle large amounts of data in a reasonable amount of time. A practical example will be shown of truss bridge element research.

8

Influence of Al2O3 nanoparticle mass concentration and aerosol formation parameters on tool vibration during turning of Ti6Al4V titanium alloy

Dylewicz Weronika, Szczotkarz Natalia, Maruda Radosław, Gupta M. K.

International Journal of Applied Mechanics and Engineering

|

2024

|

Vol. 29, no. 2

52--66

EN

Machining difficult-to-cut materials involves challenging machining conditions, including higher temperatures in the cutting zone, cutting forces and friction. Another important phenomenon is vibration, which is undesirable when manufacturing high quality workpieces. One way to reduce vibration in the cutting zone is to use cooling methods. Due to its environmentally friendly nature, the minimum quantity lubrication (MQL) method has already been widely used in metalworking. However, when combined with nanofluids, it improves the ability of the aerosol to dissipate more heat and increase lubrication in the cutting zone. This paper presents the effect of a polyol ester-based Al2O3 nanofluid due to the varying mass concentration of nanoparticles on the vibration during turning of Ti6Al4V alloy and compares the results with dry cutting and the MQL method without nanoparticles. Four concentrations (0.25−1 wt%), variable nanofluid flow rate E = 0.388−1.182 g/min and air flow rate P = 10−40 l/min were considered. According to the statistical analysis, the most important factor influencing tool vibration was the mass concentration of nanoparticles in the cutting fluid. By combining the MQL method with 0.5 wt% Al2O3, the vibration acceleration RMS values were found to be the lowest. When compared to the MQL method without nanoparticles, the RMS values for dry cutting ranged from 17.8% to 24.9%, and for wet cutting they were reduced by about 10.9-18.5%.

9

Ograniczanie drgań układu wentylator-silnik elektryczny na przykładzie remontowanej instalacji wentylacyjnej - studium przypadku

Walaszczyk Juliusz

Instal

|

2024

|

nr 2

36--43

PL

W ostatnich latach coraz mniej uwagi przykłada się do elementów związanych z prawidłową amortyzacją maszyn wirnikowych (wentylator - silnik, pompa - silnik itd.). W pogoni za ograniczeniami, przede wszystkim kosztów inwestycyjnych, nierzadko podejmowane są pochopne decyzje związane z „odchudzaniem” ram podporowych czy fundamentów pod maszyny wirnikowe. Dla zobrazowania skutków takich działań w artykule przedstawiono i omówiono wyniki pomiarów drgań wykonanych w obiekcie rzeczywistym przed oraz po wymianie instalacji wentylacyjnej obsługującej halę przemysłową. Wyniki pomiarów zestawiono z wynikami obliczeń wykonanych na podstawie 3 metod teoretycznych. Wykazano, że odpowiednia masa ramy podporowej oraz staranne wypoziomowanie układów mają decydujący wpływ na uzyskiwane amplitudy drgań. Tezę tę udowodniono poprzez ograniczenie drgań z 16,39 mm/s RMS do 4,23 mm/s RMS. Wykazano, że regularne monitorowanie amortyzacji może skutecznie i szybko doprowadzić do wykrycia problemów związanych z pracą wentylatorów i silników (uszkodzenie łożysk, niebezpieczne amplitudy drgań przegród budowlanych).

EN

In recent years, less and less attention has been paid to elements related to the proper depreciation of rotating machines (fan - electric motor, pump - electric motor, etc.). In the pursuit of reductions, especially in investment costs, hasty decisions are often made related to “slimming” support frames or foundations for rotating machines. To illustrate the effects of such actions, the article presents and discusses the results of vibration measurements performed in a real facility before and after replacing the ventilation installation that serves an industrial hall. The measurement results were compared with the results of calculations made based on 3 theoretical methods. It has been shown that the appropriate mass of the support frame and careful levelling of the systems have a decisive impact on the vibration amplitudes obtained. This thesis was proven by reducing vibrations from 16.39 mm/s RMS to 4.23 mm/s RMS. It has been shown that by regular monitoring of isolators depreciation one can effectively and quickly detect problems related to the operation of fans and electric motors (damage to bearings, dangerous vibration amplitudes of building partitions).

10

A fuzzy logic modelling of predictive maintenance in rotating machinery

Prommachan W., Surin P., Srinoi P., Pipathattakul M.

Archives of Materials Science and Engineering

|

2024

|

Vol. 126, nr 1

15--22

EN

Purpose: The study aims to investigate and assess the application of Fuzzy Logic to construct a predictive maintenance model for rotating machinery. Design/methodology/approach: The research uses a mixed approach, with both quantitative and qualitative approaches, and are four main steps: 1) surveying and analysing existing predictive maintenance techniques; 2) determining appropriate expert assessment criteria for predictive maintenance techniques; 3) vibration analysis by the experts; 4) evaluate the performance of rotating machinery with fuzzy logic. Findings: The result of the study will be used to build a rotating machinery predictive maintenance model, which is very similar to the traditional method. The obtained data showed that the efficiency of the rotating machinery and the vibration level were compliant with the standard ISO 10816-3. Thus, such data can be planned for maintenance to maximize benefit. Research limitations/implications: Future research should optimise the model and add additional modules for automatic data collection. The production monitoring system should help collect data by considering downtime, predicting the functional service life of rotating machinery, etc. Practical implications: The proposed model can be used in small water pumps in order to perform predictive maintenance. The conceptual framework was tested, particularly with rotating machinery. Originality/value: The fuzzy logic model is described as the fuzzy of a process with linguistics for greater clarity.

11

Investigation of The Effect of Mechanical Vibration Applied During Solidification on The Microstructure and Properties of Aluminum 356 Alloy

Özgü Taha Süreyya, Çalın Recept, Tanış Naci Arda

Archives of Foundry Engineering

|

2024

|

Vol. 24, iss. 1

26--31

EN

Manufacturing by casting method in aluminum and its alloys is preferred by different industries today. It may be necessary to improve the mechanical properties of the materials according to different industries and different strength requirements. The mechanical properties of metal alloys are directly related to the microstructure grain sizes. Therefore, many grain reduction methods are used during production or heat treatment. In this study, A356 alloys were molded into molds at 750°C and exposed to vibration frequency at 0,8.33, 16.66, 25, and 33.33 Hz during solidification. Optical microscopes images were analyzed in image analysis programs to measure the grain sizes of the samples that solidified after solidification. In addition, microhardness tests of samples were carried out to examine the effect of vibration and grain reduction on mechanical behavior. In the analyzes made, it was determined that the grain sizes decreased from 54.984 to 26.958 μm and the hardness values increased from 60.48 to 126.94 HV with increasing vibration frequency.

12

Seismic performance of structure equipped with a new rubber bracing damper system

Hejazi Farzad, Farahpour Hengameh, Ayyash Najad

Archives of Civil and Mechanical Engineering

|

2024

|

Vol. 24, no. 1

art. no. e46, 2024

EN

Nowadays, vibration energy absorption devices are widely implemented in many buildings subjected to severe vibration due to natural hazards, such as earthquakes, strong winds, and typhoons. Recently, viscous dampers have been commonly used in many structures as the most conventional damper type. However, the high maintenance cost resulting from oil leakage from cylinder seals has prompted researchers to seek an alternative system to viscous damper systems. Therefore, the main aim of this research is to develop a new rubber bracing damper (RBD) system by implementing high damping rubber material as a viscoelastic material to be installed in framed structures as diagonal bracing members. This will help dissipate vibration effects on the structure. To achieve this, the initial design for the RBD device has been developed, and finite-element simulation has been conducted to evaluate the behavior of the proposed RBD under various dynamic loading conditions. To define the viscoelastic material properties in finite-element modeling, high damping rubber material has been produced and experimentally tested to determine the numerical model of the material. Subsequently, the test data were utilized to develop the analytical model of the RBD device, and its performance was evaluated by applying cyclic loads and conducting nonlinear analysis. Furthermore, a series of cyclic dynamic tests with various displacement amplitudes and frequencies have been conducted on the prototype of the RBD device based on the finite-element results. Finally, to analyze the dynamic behavior of the structure equipped with RBD, a finite-element model of a three-story reinforced concrete frame structure furnished with RBD dampers has been developed. The response of the structure has been evaluated under seismic loads, and a parametric study has been conducted to investigate the response of the structures with various rubber properties. The numerical analysis results indicated that the implementation of the RBD device leads to a reduction in the occurrence of plastic hinges and lateral displacements of the structure by up to 69%. This demonstrates the efficiency of the RBD device in diminishing the seismic load effect on the structure’s response.

13

Operation of a new single-vibrator conveyor on the falling slope of the second resonance

Żmuda Weronika, Czubak Piotr

Transport Problems

|

2023

|

T. 18, z. 4

223--232

EN

The paper presents the possibilities of operating an innovative single- vibrator-driven vibratory conveyor [1] in the vicinity of the second resonance zone. The characteristics of operation on both ascending and descending slopes are presented. The differences in the suspension deflection of the additional mass (which is a dynamic eliminator) during operation before and after the resonance were analyzed. We proposed working on the descending slope of the second resonance in order to increase the durability of the device. This is because the amplitude of the suspension deflection of the additional mass is limited and, due to its high stiffness, is exposed to material fatigue. This is an unusual method of operation for conveyors because it carries certain risks, such as the risk of the device entering resonance on its own or the problem of maintaining constant angular velocity of the unbalanced masses. This paper presents both analytical and simulation studies, which were then confirmed on a laboratory stand designed and built by the authors.

14

Evaluation of vibration and noise characteristics of a compression-ignition engine fuelled with natural gas-biodiesel dual fuel

Stravinskas Saulius, Rimkus Alfredas, Matijošius Jonas

Transport Problems

|

2023

|

T. 18, z. 1

67--74

EN

As environmental requirements become more stringent and the planet becomes more polluted, the replacement of conventional diesel is attracting more interest. For alternative fuels, such as biodiesel and natural gas, to be used, their effects must be examined not only in terms of the engine’s environmental indicators but also in terms of engine vibrations and sound pressure. This study examined the influence of dual fuel – biodiesel and natural gas – on vibrations and sound pressure of a compression-ignition (CI) engine. Conventional diesel or hydrotreated vegetable oil biodiesel was used as a pilot fuel for gas ignition. The gaseous fuel was natural gas, which was injected into the intake manifold with different energy shares of the gaseous fuel (40%, 60% and 80%). Tests were performed at a constant engine crankshaft speed and a fixed start of pilot fuel injection of 6° BTDC while the fuel composition and engine load were changed. This experiment revealed correlations between gas energy share (GES) in liquid fuel and ecological and energy indicators of a CI engine.

15

Noise emission and vibration study of a mista rd-165 fhad grader to reduce environmental harmful impact

Kobiałka Janusz, Barszcz Andrzej

Technologia i Automatyzacja Montażu

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2023

|

nr 2

50--55

EN

Construction machinery noise emission and vibration on the operator site are the most important harmful factors having impact on human health. They affect for people working on the operators and as well as other persons around the machine. The article concerns the issues of noise level and noise emission measurements applied to the earthmoving machinery which are covered by the EU directive 2005/88/EC. The methods of noise testing during design and in the certification, process has been described. The basic information about testing the noise emission to the environment has been presented. Methods and results of vibration tests affecting the operator are also presented. The reference documents and EU standards concerning this topics have been described. The noise testing methods has been presented based on the prototyping and R&D cycle of the Mista RD-165 FHAD grader which is subjected to the European noise limits. The results of noise measurements and sound power level determination has been presented. The testing procedure implemented during two stages of R&D cycle. The article describes the effects of the improvements in the grader focused on noise emission limitation limits.

PL

Hałas emitowany przez maszyny budowlane jest jednym z głównych czynników szkodliwych wpływających na środowisko, a szczególnie na zdrowie osób przebywających w obszarze oddziaływania tych maszyn. Narażonym na hałas poddane są osoby bezpośrednio zaangażowane w pracę, ale również inne osoby znajdujące się w otoczeniu maszyny. Artykuł porusza zagadnienia badania hałasu i drgań miejscowych w maszynach budowlanych podlegających pod dyrektywę Unii Europejskiej 2005/88/WE. Omówione zostały sposoby badania hałasu w trakcie produkcji i certyfikacji maszyn. Przedstawiono podstawowe informacje dotyczące przeprowadzania badań emisji hałasu do otoczenia. Przywołano dokumenty odniesienia i normy badawcze które regulują te badania. Na przykładzie równiarki drogowej Mista RD-165 FHAD, która podlega limitom emisji hałasu, przedstawiono prowadzenie badań podczas prac badawczo-rozwojowych. Przedstawione zostały wyniki pomiarów hałasu i wyznaczona moc akustyczna maszyny. Badania były wykonywane na dwóch etapach prac konstrukcyjnych. W artykule zaprezentowano efekty prac doskonalących konstrukcję pod względem zmniejszenia emisji hałasu do otoczenia.

16

Operating characteristics of bearings with magnetic nanoparticles doped lubricant

Krenicky Tibor, Mascenik Jozef, Coranic Tomas, Ruzbarsky Juraj

Mining Machines

|

2023

|

vol. 41, iss. 3

168--174

EN

The main aim of the presented research was to investigate theoperational characteristics of a bearing when alternative lubricants were used for comparison with a standard lubricant, including that containing magnetic nanoparticles. The bearing was subjected to varying operating conditions, differing in terms of mechanical load status. The monitoring of the bearing operation parameters primarily focused on monitoring the velocity and acceleration of vibrations, as well as the operating temperature of the bearing. Thebearingwith lubricant doped by magnetic nanoparticles exhibited reduced vibration velocity and acceleration values both under no load conditions and when subjected to a mechanicalload. The operating temperature slightly increased during testing in the case ofthe bearing with nanoparticles compared to the bearing using the original lubricant.

17

Analysis of the influence of adding rubber recyclate on the strength properties of epoxy-glass composites

Abramczyk Norbert, Żuk Daria, Panasiuk Katarzyna

Journal of KONBiN

|

2023

|

Vol. 53, iss. 1

1--24

EN

The article attempts to assess the possibility of using rubber recyclate as a component of composite materials. Research is being carried out to develop a technology for the production of composite materials with the addition of rubber waste. These tests are aimed at increasing the reliability and safety of the operation of structures exposed to longterm impact of devices generating vibrations. At the same time, work is underway on the use of complex composite surfaces as sound-absorbing elements. The new direction of using recyclates will have a positive impact on the management of environmentally harmful waste, taking into account a favorable economic factor.

PL

W artykule podjęto próbę oceny możliwości wykorzystania recyklatu gumowego jako składnika materiałów kompozytowych. Prowadzone są badania mające na celu opracowanie technologii wytwarzania materiałów kompozytowych z dodatkiem odpadu gumowego. Badania te są ukierunkowane na zwiększenie niezawodności i bezpieczeństwa obsługi konstrukcji narażonych na długotrwałe oddziaływanie urządzeń generujących wibracje. Jednocześnie trwają prace nad wykorzystaniem złożonych powierzchni kompozytowych jako elementów dźwiękochłonnych. Nowy kierunek wykorzystania recyklatów będzie miał korzystny wpływ na zagospodarowanie szkodliwych dla środowiska odpadów z uwzględnieniem korzystnego czynnika ekonomicznego.

18

Influence of the specific load on stability and vibrations of the multimember column with internal cracks

Sokół Krzysztof, Kuliński Krzysztof

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2023

|

Vol. 71, nr 4

art. no. e146408

EN

Slender systems are mostly studied when Euler’s load or follower load is considered. The use of those types of external loads results in well-known divergence or flutter shape of the characteristic curve. In this study, one takes into account the specific load which allows one to obtain an interesting divergence – pseudo flutter shape of characteristic curves on the external load–vibration frequency plane. The curves can change inclination angle as well as one can observe the change in vibration modes along them. The shape of those curves depends not only on the parameters of the slender system but also on loading heads that induce the specific load. In this study, one considers the slender multimember system in which cracks are present and weaken the host structure. The results of theoretical as well as numerical simulations are focused on the influence of the parameters of the loading heads on vibrations, stability, and loading capacity of the investigated system as well as on the possibility of partial reduction of unwanted crack effect.

19

Forecasting the Natural Frequency of the Brake Disccasting

Zyska Andrzej, Bieroński Mariusz

Archives of Foundry Engineering

|

2023

|

Vol. 23, iss. 4

87--92

EN

The paper presents the results of calculations and measurements of the first natural frequency of castings of solid and ventilated brake discs made of gray cast iron of the EN-GJL-200 class. The tests were carried out for three types of chemical composition, taking into account the permissible minimum and maximum content of alloying elements. Numerical simulations of natural vibrations were carried out on the basis of our own production material databases. To determine the elastic properties of cast iron, the ultrasonic method with the measurement of the propagation velocity of longitudinal and transverse waves was used. Measurements were made directly on casts of raw discs of various thicknesses. The values of Young's modulus and Poisson's number calculated from ultrasonic measurements were used to define the stiffness matrix in the equilibrium equation, which is solved by the solver of the MSC Nastran program. A high compatibility between the results of numerical simulations and the results of experimental FRF frequency analysis was obtained. The differences between the calculated and actual values were at the level of several hertz, while the estimated average error of numerical simulations was 0.76%. It was also found out that cast iron melts for brake discs must be subject to strict control in terms of chemical composition. Slight deviations of the eutectic saturation coefficient from the optimal value cause a significant change in the first natural frequency of the brake discs, regardless of their geometry.

20

Vibration analysis of an Airlie beach house: a case study in Australia

Wheatley Greg, Babamiri Arash, Philippa Bronson

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2022

|

z. 114

179--192

EN

Airlie beach houses are quite common in the coastal areas of Australia. These houses, similar to other buildings, provide comfort for their residents. House comfort is not limited to temperature or sound pollution, vibration can be considered as another equally important factor. In this article, the vibration of an Airlie beach house was investigated. The base steel structure was modeled in SolidWorks and Space Gass for evaluating stress distribution and nodal displacement, respectively. To find the root cause of the distressing vibration of the house, which was felt with dwellings, the axial acceleration of the house’s structure was determined. Some feasible solutions such as adding a fiber-reinforced polymer joist hanger, inserting additional rubber padding to the joist hanger, and attaching additional bracing, were discussed and a cost analysis was considered for the solutions. Eventually, the nature of the best solution, which was adding rubber, was tested experimentally.