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Mechanics wydawana w latach 2005-2009. Kontynuowane w latach 2010-2016 pod tytułem Mechanics and Control

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Now showing 1 - 10 of 169
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Active control of vibrations of a three-axis gyroscopic platform on board of a flying object
    (Wydawnictwa AGH, 2005) Koruba, Zbigniew; Styczeń, Jerzy
    The work presents an algorithm for active control of vibrations of a three-axis gyroscopic platform during pre-programmed and stabilised operation on board of a flying object. The considerations focus on disturbances resulting from the flying object manoeuvres and short-duration pulses of external forces under the conditions of friction in the bearings and non-linear platform operation range.
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    Item type:Article, Access status: Open Access ,
    Techniques of neural networks for signal parameterization used in monitoring systems
    (Wydawnictwa AGH, 2008) Wszołek, Wiesław
    The paper presents selected aspects of research concerning a new concept in application of computer technology to the analysis of acoustic signal. This new concept assumes, that during the analysis of signal the study is not focused on determining some or other signal parameters, neither it is focused on the signal classification, but it is supposed to lead to an automated understanding of the origins of the deformation, which can be revealed in analyzed signal.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Stress analysis in helical springs with closed end coils machined from cylindrical sleeves
    (Wydawnictwa AGH, 2006) Salawiński, Józef; Michalczyk, Krzysztof
    The review of stress calculation methods in helical springs with rectangular cross-section wire is introduced in this paper. It is demonstrated that methods described in literaturę have various accuracy. Also, the modern construction of helical spring machined from tubular blanks is presented. It is indicated, using Finited Elements Me-thod, that existing for classical springs with opened ends stress calculating methods, are not suitable for springs with capped ends, because the stresses calculated from them are much smaller than the real ones.
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    Item type:Article, Access status: Open Access ,
    Hybrid model of the conventional power unit
    (Wydawnictwa AGH, 2008) Rusinowski, Henryk; Szapajko, Grzegorz; Stanek, Wojciech
    The paper presents the hybrid model of the conventional power unit. The model contains following fragmentary models: model of the boiler, turbine and regenerative heat exchangers. Fragmentary models have been elaborated with the application of the analytical modelling methods, regression and neural networks. Hybrid model of the boiler contains balance model compatible with the German norm DIN and regressive models describing content of the unburnt combustibles in the slag and in the dust and the neural model describing the flue gases temperature at the outlet of the boiler. Model of the turbine contains balance model and theoretical-empirical model of the steam expansion line in the turbine. Models of the heat exchangers contain the balance and empirical models describing the heat transfer. The paper presents the exemplary calculation results and their comparison with the measurements.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Calibration of the strip yield model for fatigue crack growth predictions in structural steel
    (Wydawnictwa AGH, 2009) Machniewicz, Tomasz
    The paper is focused on the calibration of the strip yield (Dugdale) model for crack growth predictions for structural steel. This is achieved by imposing appropriate constraints on yielding the strip elements. To avoid a fortuitous, i.e. physically unjustified choice of the constraint factors, a novel concept for their selection is proposed, namely matching the experimentally observed and predicted by the model cyclic stress-strain behaviour at the crack tip. The approach is shown to yield satisfactory prediction results on crack growth under constant amplitude loading and after application of an overload cycle.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Multi-channel virtual-microphone feedback minimum-variance active noise control system
    (Wydawnictwa AGH, 2009) Pawełczyk, Marek
    Classical active noise control systems are designed to minimise, in a sense, the residual signal at the microphone providing information about acoustic noise and secondary sound interference. The secondary sound operates at the same time on the acoustic noise at other positions including user ears. In the worst case this can result in sound reinforcement at those positions. In many applications placing another microphone directly at the ears is not accepted. It is then justified to make efforts to design a dedicated system. The purpose is to minimise the mean-square value of the noise at the desired location while performing measurements of sound interference results at another location. This can be done by employing the general idea of Vrtual-Microphone Control systems. However, for many active noise control applications the use of a single pair of microphone and loudspeaker does not suffice to obtain satisfactory performance, i.e. generate a zone of quiet of acceptable dimensions. Moreover, for some applications, presence of an obstacle, e.g. the head in an active headrest system, constitutes a barrier for the zone of quiet at one side to propagate to the other side. Therefore, more microphones and loudspeakers are often necessary. In the most general case a coupling between subsequent pairs should be taken into account resulting in a multi-channel system. In previous papers of the author adaptive systems have been designed and analysed. In this paper a fixed parameter multi-channel Virtual-Microphone Control system, optimal in the mean- square sense, is designed. It includes non-minimum phase property of the system channels. Both the case of more inputs than outputs as well as the case of more outputs than inputs are considered. Factorization techniques have been used for the design. The system is verified by successfully controlling noise for the active headrest system.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Experimental study of vibration control in a two-degree-of-freedom pitch-plane model of a magnetorheological vehicle suspension
    (Wydawnictwa AGH, 2007) Martynowicz, Paweł; Sapiński, Bogdan
    The paper concerns the vibration control in a two-degree-of-freedom model of vehicle suspension equipped with independently controlled MR dampers in front and rear sections. The suspension model was tested in open-loop and feedback system configurations under harmonic and square base excitations. The experiments were conducted on the specially designed laboratory setup with data acquisition and control system configured in MATLAB/Simulink environment. The obtained results reveal effectiveness of MR dampers in vibration isolation for a wide range of excitation frequencies.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Podobieństwa i różnice w zakresie statyki sekcji obudów ścianowych
    (Wydawnictwa AGH, 2005) Losiak, Stanisław; Ptak, Jan; Blaschke, Janusz
    In the paper schemes of basic group of supports with distribution of loads for three types of units have been presented. It has been demonstrated that schemes with load distribution may be reduced to one collective scheme and a common mathematical description for various types of units may be presented. Application of the common description for testing the characteristics of the units of the same type were discussed. In general, equations for determining the static parameters of the support unit with stretcher cylinder were given. Static-stability characteristics of such a support unit on the basis of exemplary characteristics determined from mathematical description were discussed.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Stress analysis in slotted springs
    (Wydawnictwa AGH, 2006) Michalczyk, Krzysztof
    In this paper the modern construction of slotted springs was presented. It was proven that maximal stresses in such springs under load have higher values than the stresses calculated with previous method. The new model of phenomena and calculating method based on it was proposed. The new method gives results closer to FEM analysis than the previous.
  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Analiza techniczna i ekonomiczna rekonstrukcji czerpaków dla koparek kołowych SCHRS 4000 urabiających caliznę w KWB «Bełchatów»
    (Wydawnictwa AGH, 2005) Badura, Sławomir; Łopata, Antoni Mieczysław
    The paper presents technical and economical analysis of the reconstruction for symmetrical and asymmetrical bucket mounted on the bucket wheel excavators SchRs 4000 in the targets to dredging mineral.