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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).
EN
The new vibratory conveyor, which is during patent pending [1], equipped with a single electro-vibrator intended for an accurate material dosing, was investigated in the hereby study. Possibilities of material transportations and dosing both in and out the circum-resonant zone were investigated. Dependencies of the transport velocity of the tested conveyor as functions of the excitation frequency for a certain range of load were determined. The high usefulness of the machine in the production lines requiring accurate material dosing was indicated. It was pointed out that the conveyor can transport the feed at a constant velocity, regardless of the feed mass, which is unique for the conveyors of inertial drive.
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.
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.
5
Content available Vibroacoustic Helicopter Impact on Elevated Helipad
EN
A helicopter landing and taking off on an elevated helipad is a source of noise that affects the environment and causes vibrations of the landing pad or the building infrastructure. Vibrations are also excited by the air stream flowing through the main rotor and transferred to the landing pad by contact of the helicopter chassis. Vibrations are transferred to the building through the structure of the helipad. Depending on the damping properties of the structure and the vibro-isolating elements used, vibrations can be felt in rooms used by people and also transmitted to devices located in the building. The subject of the study described in this paper is the vibroacoustic effects of an EC-135 helicopter on an elevated landing pad during landing, standstill with the propulsion system engaged and take-off. Measurements of vibrations and noise were made at points located both on the landing pad and in the building. The paper presents selected results of measurements in various phases of flight and helicopter manoeuvres. The frequency analyses of the fragment of the measurement data for the flight phase, in which the highest levels of impact were recorded, were also performed and included. The results are presented as graphs and annotated.
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.
PL
Artykuł przedstawia propozycje wytycznych do precyzyjnych pomiarów niwelacyjnych wykonywanych w warunkach drgań. Proponowane rozwiązanie w pewnym stopniu redukują niekorzystny wpływ drgań na dokładność i wiarygodność pomiarów niwelacyjnych. Wytyczne zostały opracowane na podstawie badań wykonanych w symulowanych warunkach drgań na testowej sieci reperów. Na podstawie wyników badań zdefiniowano najważniejsze czynniki wpływające na dokładność niwelacji wykonywanej w strefie drgań, do których zaliczono kierunki drgań, konstrukcję sieci pomiarowej, parametry drgań oraz podatność samego niwelatora na drgania. W artykule zaprezentowano także przykładowe zależności między dokładnością wyznaczenia przemieszczeń pionowych a niektórymi parametrami drgań.
EN
This article presents guideline proposals for precise levelling measurements carried out under vibration conditions. The proposed solutions reduce to some extent the adverse effects of vibrations on the accuracy and reliability of levelling measurements. The guidelines were based on research carried out under simulated vibration conditions on a test levelling network. Based on the research results, the most important factors influencing the accuracy of leveling performed in the vibration zone were defined, including vibration directions, construction of the measurement network, vibration parameters and the sensitivity of the level itself to vibrations. The article also presents example relationships between the accuracy of determining vertical displacements and some vibration parameters.
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.
EN
We investigate the dynamic behavior of a rectangular orthotropic plate loaded with the concentrated force moving with constant speed along the structure. In this work, we consider two types of plates in terms of boundary conditions. In the first case, we assume that the plate is simply supported on all of its edges with a number of point supports arbitrarily located in its area, and in the second one, we look at a two-span bridge plate with arbitrarily oriented intermediate linear support. Solutions for both cases are obtained by replacing the original structure with a single-span plate subjected to a given moving load and redundant forces situated in positions of removed intermediate supports. Redundant forces are obtained by the application of Volterra integral equations for the simply supported plate, and finite difference discretization and the Newmark method for the bridge plate. Two numerical examples are given to prove the effectiveness of the presented approach.
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.
EN
Quenching technology requires the use of media with different cooling intensities and various shapes of cooling curves that show different particularities compared to that of conventional media such as water, oil, or emulsions. The use of synthetic quenching media is relatively new and also has multiple advantages such as non-flammability, safety in use and low cost. In this study, the cooling media tested was obtained by mixing 2 wt% carboxymethyl cellulose with 2 wt% NaOH in one litter of water. Moreover, three different temperatures (20°C, 40°C and 60°C) of the quenching media were evaluated. By dissolution in water, a synthetic solution with low viscosity, surfactant and lubricant was obtained. Because carboxymethyl cellulose is a biodegradable organic material, that is obtained as a by-product in the manufacture of paper, a basic substance with a preservative effect was added. According to this study, both the variation diagram of the heat transfer coefficient and the diagram of the cooling rates, during the cooling stages give important indications regarding the use of a liquid cooling medium for quenching.
EN
The aim of this study is to determine the effect of environmental factors in the form of UV radiation and temperature on the amplitude-frequency behaviour of polymer composites (prepregs) based on a framework of thermosetting epoxy resin reinforced with high-strength R-glass fibres. Two series of composites with different fibre arrangements were prepared. The series had fibres arranged at angles of 30°, 45°, and 60°, at symmetric and asymmetric orientations in relation to the central layer. The composites were subjected to conditioning which simulated a six-month period of use in the spring and summer in the temperate warm transitional climate of Central and Eastern Europe. An UV QUV/SPRAY/RP accelerated aging chamber manufactured by Q - Lab Corporation was used for this purpose, and UV-A 340 lamps were used to simulate daylight. In addition, varying loads caused by sudden temperature changes were simulated using the Thermal Shock Chamber T/60/V2 Weisstechnik. Conditioned samples were tested using a TIRAvib 50101 electromagnetic exciter in combination with an LMS Scadias III controller and Test.Lab software. The results of the tests, in the form of amplitude-frequency diagrams in resonance regions, indicated that certain changes occurred as a result of the conditioning, which is a new development in the area of material tests. The results shed light on the effects of environmental conditions on the stiffness characteristics of composites, causing dynamic nonlinearities when operating at resonant frequencies.
EN
The article presents the results of experimental research and simulation analyses of the influence of slip velocity, normal pressures and vibration frequency on the effectiveness of friction force reduction carried out in sliding motion in the presence of forced tangential vibrations. In experimental studies, changes in the driving force were measured during the slip of the upper body over the vibrating lower body. The direction of these vibrations was parallel both to the contact plane and to the direction of movement of the shifted body. The simulation tests were carried out in the Matlab/Simulink environment through the use of numerical procedures that were specially created for this purpose. Dynamic friction models considering the tangential compliance of contact and the phenomenon of pre-sliding displacement were used for calculations. The paper presents the designated values of the so-called coefficient of average friction force reduction in sliding motion for the following friction pairs: steel C45–steel C45, steel C45–cast iron GGG40 and steel C45–polytetrafluoroethy-lene PTFE (Teflon). The results of numerical analyses were in good agreement with those of experimental tests. A significant dependence of the level of average friction force reduction on the frequency of forced vibrations, sliding velocity as well as the kind of sliding pair material, and normal pressures was shown.
PL
Na przykładzie hydrogeneratora rewersyjnego o mocy 57,6/75 MVA przedstawiono wyniki badań kształtu stojana i wirnika. Omówiono wpływ odkształceń badanych elementów na drgania hydrogeneratora w różnych stanach obciążenia.
EN
The results of the research on the shape of the stator and rotor are presented on the example of a reversible hydrogenerator with a capacity of 57,6 / 75 MVA. The influence of deformations of the tested elements on the vibrations of the hydrogenerator in various load conditions was discussed.
15
Content available Transport features of a new, self-attuned conveyor
EN
The new vibratory conveyor destined for the accurate dosing of materials was investigated in the present work. The possibilities of the system to transport materials in the circum-resonant zone were tested analytically, as well as by simulations. The optimal work point of the system, which allowed a decrease in the amplitude of eliminator vibrations on its suspension due to operations on the resonance slope, was determined. Transport velocities depending on the excitation frequency and feed mass were determined by simulations. The results were verified on the conveyor of industrial dimensions designed and built in accordance with the patent application.
EN
Vibration diagnostics is of particular importance in rail transport safety systems because the signals received from vibration sensors installed on rolling stock, bridges, tunnels, and other infrastructure objects have great diagnostic information potential. Despite this, in practice, there are cases when the adequacy of the results of the vibration control and diagnostics task is not ensured. The reason is that the sampling step of the vibration signal does not change when the train speed changes. Given the need to change the sampling interval depending on the train speed, this article proposes an adaptive technology for vibration signal sampling that allows the building of intelligent systems of adaptive vibration control of malfunctions in rail transport.
EN
In the present study, a new vibratory conveyor (patent pending) equipped with a single electro-vibrator intended for an accurate material dosage is investigated. The possibilities of material transportation in the circum-resonant zone were investigated analytically and by simulations [1]. Furthermore, the dependencies of the transport velocity of the tested conveyor as functions of the excitation frequency were determined. Favorable excitation frequencies at transports in the main and reversal directions were found, and the high usefulness of the machine in the production lines requiring accurate material dosage was indicated. A control strategy allowing for a sudden stop of the transported material was also proposed.
EN
This article is a continuation of work aimed to identify vibrations. It contains the results of tests, calculations, and analyses in the field of vibrations occurring on the elements of equipment of the N10 group tracked vehicle and the N11 group armored wheeled vehicle (classification according to NO-06-A103:2005) equipped with manually operated weapon systems. A detailed description of the analyses carried out, and the results of the research on the N10 group vehicle are contained in the article: "The Problem and Analysis of Vibrations Appearing in an N10 Group Military Vehicle Fitted with a Manually-Operated Armament Module" published in the quarterly Problems of Mechatronics Armament, Aviation, Safety Engineering. This study thoroughly presents the test results and their analysis for the N11 group vehicle and only recalls the results of similar tests and analyses for the N10 group vehicle for comparison. The research aimed to get acquainted with the characteristics of vibrations occurring in stabilized turret systems (weapon system) and devices supplying turret systems in terms of amplitudes, practical values, and their energy for various operating conditions. The analyses were carried out concerning the requirements of the Polish defense standard NO-06-A103:2005 and MIL-STD-810F regarding the correctness of their application.
PL
Artykuł to kontynuacja prac, celem których jest poznanie rzeczywistych wibracji. Zawiera wyniki przeprowadzonych badań, obliczeń i analiz w zakresie wibracji występujących na elementach wyposażenia pojazdu gąsienicowego z grupy N10 oraz opancerzonego pojazdu kołowego z grupy N11 (klasyfikacje wg NO-06-A103:2005) wyposażonych w ręcznie sterowane systemy uzbrojenia. Szczegółowy opis przeprowadzonych analiz oraz wyniki badań w zakresie pojazdu grupy N10 zawarte są w artykule: „The Problem and Analysis of Vibrations Appearing in an N10 Group Military Vehicle Fitted with a Manually-Operated Armament Module” opublikowanym w kwartalniku Problems of Mechatronics Armament, Aviation, Safety Engineering. Niniejszy artykuł gruntownie prezentuje wyniki badań oraz ich analizy dla pojazdu grupy N11 i przywołuje jedynie wyniki analogicznych badań i analiz dla pojazdu grupy N10 w celu ich porównania. Przeprowadzone badania miały na celu zapoznanie się z charakterystyką drgań występujących na stabilizowanych systemach wieżowych (systemie uzbrojenia) oraz urządzeniach zasilających systemy wieżowe w aspekcie amplitud, wartości skutecznych oraz ich energii dla różnych warunków eksploatacji. Analizy przeprowadzono w odniesieniu do wymagań polskiej normy obronnej NO-06-A103:2005 oraz MIL-STD-810F w aspekcie słuszności ich stosowania.
EN
There are numerous non-destructive methods in welded joints investigation, but the most promising, especially in applications with steady monitoring of the structure, is the vibro-diagnostic approach. In the course of the research work, the responses were obtained and detected by accelerometers, providing valuable diagnostic information, which later was mathematically processed in the field of time or frequency. The mathematical processing aimed to distinguish significant characteristics embedded in the processes typical of the investigated joints and allow an assessment of how they were made. For this purpose, two methods were proposed, based on determining the logarithmic decrement as a function of time. Due to the complicated course of the impact responses, the method of calculating the logarithmic decrement has been suggested, involving the approximation of responses with various functions. According to the research, the analysis of changes in the logarithmic decrement as a function of time applied to welded plates was proposed, as it enables the initial assessment of joint quality.
20
Content available remote Investigation of passenger ride comfort in selected means of transport
PL
Zagadnienie komfortu jazdy staje się coraz istotniejsze ze względu na rosnące wymagania pasażerów. Podnoszenie jego poziomu może mieć też na celu zachęcenie do zmiany nawyków osób, które na co dzień wybierają podróż samochodem osobowym. Badania nad komfortem jazdy w tradycyjnym ujęciu skupione są gównie na ocenie oddziaływania drgań mechanicznych na organizm człowieka. Nie są to jednak jedyne czynniki, które mają znaczący wpływ na odczucia i zadowolenie pasażerów. W artykule przedstawiono metody oceny komfortu jazdy, które uwzględniają zarówno drgania mechaniczne, jak i hałas, dla których wymagania zostały określone w odpowiednich normach i przepisach. Ponadto, przedstawiono wyniki pilotażowych badań komfortu jazdy w wybranym pojeździe szynowym na podstawie dwóch czynników wpływających na komfort jazdy. Ocenie podlegał komfort wibracyjny i akustyczny. Do analizy drgań wykorzystano metodę spektralną zgodną z normą ISO 2631-1 oraz metodę ważoną zgodną z późniejszym wydaniem normy. Zbadano też poziom równoważnego poziomu dźwięku korygowanego krzywą korekcyjną A, który został porównany z wartością dopuszczalną. W wyniku przeprowadzonych badań stwierdzono, że zarówno drgania jak i hałas negatywnie wpłynęły na poziom komfortu w badanym pojeździe.
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