Wyniki wyszukiwania - Biblioteka Nauki

1

Reduction of vibrations generated by a variable torque in 5-cylinder in-line engines

100%

Iskra A.

Journal of KONES

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2011

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tom Vol. 18, No. 4

137-140

EN

Despite undoubted advantages of a 5-cylinder in-line engine, its basic drawback is the lack of partial balancing the torque variability generated by gas forces by means of the torque caused by inertia forces. Such a desired phenomenon occurs in 4-cylinder engines. Accordingly, these engines - within a wide range of rotational speed -demonstrate greater engine smoothness than potentially better 5-cylinder engines. In the article, a concept of generating the moment of inertia forces by means of the proper rollers reducing the amplitude of the moment caused by gas forces is presented. Such a solution will allow for a significant mitigation of vibrations of 5-cylinder engines, and they are in many respects better than 4-cylinder ones, which has been justified more extensively in this article. The paper concerns the opportunity of constructing a 5-cylinder engine of the external torque stability equivalent to the torque stability of a 4-cylinder engine. It will allow obtaining a much better unit from the commonly used present 4-cylinder engines for the drive of passenger cars. An engine of the same swept capacity in the 5-cylinder rather than 4-cylinder version will be characterized by numerous advantages, and first and foremost: the space between the front wheels of the vehicle will be optimally used. 4-cylinder engine generates vary large summary forces of the 2nd order, which is manifested by intensive vibrations in the plane axis of the cylinders.

2

Application of mechanical and electrical elements in reduction of vibration

51%

Białas K.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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tom Vol. 52, nr 1

31--38

EN

Purpose: This work presents methods of reduction of the vibration of mechanical systems by means of passive and active elements as well as examples of implementation of active reduction of vibration by means of electrical elements and mechanical elements in the form of kinematic excitation. Design/methodology/approach: This work also describes a structural and parametric synthesis, which can be defined as the design of systems meeting specific requirements. These requirements refer to the frequency values of the systems’ vibration. Findings: The examples of implementation of active subsystems presented in this work point out to the fact that one can use mechanical elements as well as electrical elements to reduce mechanical vibration. By applying such elements it is possible to obtain mechanical energy necessary for the active reduction of vibration. Research limitations/implications: The deliberations presented in this paper are limited to the presentation of possible physical implementation of active elements by means of mechanical and electrical elements. In active subsystems one may also use elements from other environments. In the next phase one should analyse the resultant systems and investigate the interaction between the subsystems and the basic system. Practical implications: The results represented this work extend the tasks of synthesis to other spheres of science. The practical realization of the reverse task of dynamics introduced in this work can find uses in designing of machines with active and passive elements with the required frequency spectrum. Originality/value: The presented approach i.e. a non-classical synthetic method applied in designing mechanical systems, one (as early as at the design and construction stage) may verify future systems.

3

Computer-aided analysis and synthesis of branched mechanical systems

51%

Białas K.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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tom Vol. 45, nr 1

39--44

EN

Purpose: The main aim is to present and describe the author’s program supporting the process of analysis and synthesis of discrete vibrating mechanical systems with branched structures. Synthesis of reference concerns the reverse problem and is aimed to obtain the structure and parameters of the system that meets the previously established requirements for the values of vibrations frequencies. Design/methodology/approach: Using the program presented in this paper, it is possible to carry out the synthesis that is understood as designing of the systems. The use of such non-classical method significantly reduces designing time compared to classical methods. An important advantage of the program is a lack of need for the formulation of new mathematical models used to describe the system, with the change of its parameters or structure. The program also facilitates comparison of the passive and active vibration reduction. Findings: The presented software allows comparison of the results of the use of passive and active elements of vibration reduction of the systems under consideration. The analysis shows that active elements reduce the vibration completely and passive elements reduce the vibrations only partially. Research limitations/implications: The scope of considerations is limited to discrete longitudinal vibrating mechanical systems with branched structures containing passive or active elements for reduction of vibrations. Practical implications: The presented methods of synthesis and analysis can be useful for designers and engineers in the design and construction of this type of mechanical systems. Originality/value: The possibilities and operation of the author’s program aiding the synthesis and analysis of discrete mechanical systems are also discussed. By means of this software it is possible to carry out the analysis and synthesis of discrete systems containing both active and passive elements that reduce vibrations.

4

Application of kinematic excitation as implementation of active reduction of vibration

51%

Białas K.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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tom Vol. 47, nr 2

185--194

EN

Purpose: The work presents methods of reducing vibration with the use of passive and active elements as well as reveals the results of implementation of active reduction of vibration applying mechanical elements in the form of kinematic excitation. Design/methodology/approach: The publication also includes structural and parametric synthesis understood as designing of mechanical systems with a desired frequency spectrum and presents analysis of obtained systems in order to verify if the latter meet related requirements. Findings: The research reveals that the application of kinematic excitation as the implementation of active reduction of vibration does not satisfy expectations as obtained models are characterised by frequency spectrum different to the desired one. Research limitations/implications: The research relates only to discrete vibratory systems, in which the reduction is carried out by means of mechanical elements. It is advisable to apply another type of elements e.g. electric ones. Practical implications: The results represented this work extend the tasks of synthesis to other spheres of science e.g. electric systems. The practical realization of the reverse task of dynamics introduced in this work can find uses in designing of machines with active and passive elements with the required frequency spectrum. Originality/value: Owing to the presented approach i.e. a non-classical synthetic method applied in designing mechanical systems, one (as early as at the design and construction stage) may verify future systems.

5

Pasywne tłumiki drgań skrętnych : zespoły wspomagające niezawodność pracy jednostek napędowych pojazdów

38%

Bik T.

Autobusy : technika, eksploatacja, systemy transportowe

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2017

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tom R. 18, nr 6

535--538, CD

PL

W artykule podjęta została problematyka zwiększenia niezawodności pracy pojazdów i maszyn roboczych napędzanych przez wielocylindrowe silniki spalinowe. Jako metodę podwyższenia niezawodności wskazano możliwość ograniczenia bądź też wyeliminowania dynamicznych przyczyn powstawania uszkodzeń wałów korbowych silników. Rozważono pasywne tłumiki drgań skrętnych (gumowe i wiskotyczne) jako zespoły ograniczające amplitudy drgań skrętnych wałów w zakresie obrotowych prędkości rezonansowych (prędkości krytycznych).

EN

The reliability increasing of the vehicles and machines powered by multi-cylinder combustion engines has been considered in this article. Possibility of reducing or eliminating the dynamic causes of engine crankshaft damages has been indicated as the method for reliability development. The passive torsional vibration dampers (rubber and viscous) have been pointed as the modules limiting the amplitude of the crankshafts torsional vibrations in the range of rotational resonance speeds (critical speeds).

6

Wpływ modyfikacji zębów na zjawiska dynamiczne w przekładni zębatej w różnych warunkach eksploatacyjnych

38%

Peruń G.

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tom z. 70

71-76

PL

Artykuł przedstawia wyniki prac, mających na celu określenie wpływu modyfikacji zarysów zębów na zjawiska dynamiczne, które zachodzą w przekładniach zębatych. Wpływ modyfikacji został określony z wykorzystaniem modelu stanowiska FZG przy uwzględnieniu różnych warunków eksploatacyjnych.

7

Ochrona przed drganiami mostów o długich przęsłach

32%

Sakiewicz W.

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tom R. 21, nr 6

292-298

PL

W artykule przedstawiono najważniejsze metody kontroli drgań mostów o długich przęsłach wywołanych wiatrem. Dokonano krótkiego przeglądu mostów pod kątem zmian kształtu i wysokości dźwigara wraz ze zwiększającą się ich rozpiętością. Omówiono rodzaje wzbudzeń powstające przy oddziaływaniu wiatru na konstrukcję mostową, aby móc wskazać sposoby ich redukcji. Szczególną uwagę zwrócono na obniżenie poziomu drgań kabli poprzez zmianę jego kształtu, zmianę układu kabli. Aby uzmysłowić skalę stosowania metod redukujących wpływy dynamiczne pochodzące od działania wiatru, podano przykłady jednych z najdłuższych na świecie mostów wiszących i podwieszanych.

EN

In this paper arc presented I he most important wind-induced vibration control methods of the long span-bridges. It is performed a review of shapes of girder bridges which change with the span of bridge. II is discussed response of a long-span bridge to various wind-induced aerodynamic phenomena and is shown the means for its reduction. It is noticed the reduction of vibration level of cable by change cable shape, rearranging the cables. It is given the examples of the longest span suspension and cable-stayed bridges in the world to illustrate (he scale of applying of wind-induced vibration control methods.

8

Urządzenia pasywnej kontroli drgań w obiektach budowlanych

32%

Gołębiowska I. , Rójek J.

Ekologia i Technika

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2010

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tom R. 18, nr 5

290-298

PL

W artykule przedstawiono popularne urządzenia pasywnej kontroli drgań stosowane w obiektach budowlanych narażonych na wpływy dynamiczne. Znaczna redukcja poziomu drgań konstrukcji może być osiągnięta poprzez umieszczenie w niej dodatkowych urządzeń tłumiących. Z analizy literatury wynika, że odpowiednio zaprojektowany i umieszczony w konstrukcji budynku tłumik pozwala na efektywną kontrolę drgań. Istnieje wiele różnych rodzajów urządzeń pasywnej kontroli drgań. Każde z nich posiada charakterystyczny sposób dyssypacji energii i kontroli drgań. Urządzenia te - to urządzenia o najprostszej budowie, ekonomiczne i niezawodne. Strojone tłumiki drgań są efektywne w redukcji odpowiedzi konstrukcji obciążonej wiatrem, wymuszeniem harmonicznym czy ruchem komunikacyjnym. Natomiast, urządzenia dyssypujące energię są efektywne w obniżaniu poziomu drgań konstrukcji, spowodowanych wiatrem lub trzęsieniem ziemi.

EN

This paper reviews well-known devices of passive vibration control used in buildings which are exposed to dynamic effects. Significant reductions in response can be achieved using supplemental damping devices. The results of analysis of literature show that with the proper distribution of this dampers in the buildings engineers can control the level of vibration of construction. There arę many different types of passive dampers. Each of these devices has a unique way of dissipating energy and controlling vibrations. This devices are usually built in the simplest way, moreover they are very efficient and reliable. Tuned vibration dampers are very effective in reduction of response of constructions, which are exposed to wind effects, harmonic and traffic loadings. On the other hand, energy dissipating devices are effective in diminishing the level of vibrations, which are caused by wind or earthquake.

9

Polar graphs and structural numbers in synthesis of active and passive mechanical systems

32%

Białas K.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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tom Vol. 30, nr 1

43-50

EN

Purpose: The main purpose of this work is the presentation analysis and synthesis of mechanical systems including passive and active elements reducing vibrations. In result of conducted synthesis was received structures and parameters of a discrete model meeting the defined requirements concerning the dynamic features of the system, in particular, the frequency spectrum. The aim of this paper is also comparison of these two methods of reduction of vibrations. Design/methodology/approach: In this paper was used method of polar graphs and their relationship with algebra of structural numbers. This method is called a non-classical method. The use of such a method enables the analysis and synthesis of mechanical systems irrespective of the type and number of the elements of such a system. Findings: The application of active elements to eliminate vibration enables overcoming limitations which occur if passive elements are used. Active elements give better results in case of reduction of low frequency vibrations. Presented approach simplifies the process of selecting the dynamical parameters of systems in view of their dynamical characteristics. Research limitations/implications: The scope of discussion is analysis and synthesis of mechanical systems including passive and active elements reducing of vibrations, but for this type of systems, such approach is sufficient. Practical implications: The practical realization of the reverse task of dynamics introduced in this work can find uses in designing of machines with active and passive elements with the required frequency spectrum. Originality/value: Thank to the approach, introduced in this paper, can be conducted as early as during the designing of future functions of the system as well as during the construction of the system. Using method and obtained results can be value for designers of mechanical systems with elements reducing vibrations.

10

Reverse task of passive and active mechanical systems

32%

Białas K.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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tom Vol. 23, nr 2

51-54

EN

Purpose: The main purpose of this work is to present the algorithm of a converse problem of dynamics of mechanical systems containing passive and active elements. Solving the problem results in obtaining structures and parameters of a discrete model meeting the defined requirements concerning the dynamic features of the system, in particular, the frequency spectrum. Another objective of this work is to compare the reduction of vibration by means of passive or active elements or while using passive and active elements at the same time. Design/methodology/approach: The work involves the application of a non-classical method of polar graphs and their relation to structural algebra. The use of such a method enables the analysis of mechanical systems irrespective of the type and number of the elements of such a system. Findings: The application of active elements to eliminate vibration enables overcoming limitations which occur if passive elements are used. One of the most important limitations is low efficiency in case of low-frequency vibration and inability to reduce vibration of selected parts of the system. Research limitations/implications: The scope of discussion is reverse task of passive and active mechanical systems, but for this type of systems, such approach is sufficient. Practical implications: The practical realization of the reverse task of dynamics introduced in this work can find uses in designing of machines with active and passive elements with the required frequency spectrum. Originality/value: Thank to the approach, unclassical method of polar graphs and their relationship with algebra of structural numbers, can be conducted as early as during the designing of future functions of the system as well as during the construction of the system. Using method and obtained results can be value for designers of mechanical systems.