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This work presents basic information associated with markets of selected alternative fuels used in transport, such as methyl esters, conventional bioethanol and lignocellulosic bioethanol, and the market of electrical vehicles. Legal conditions, which stimulate development and regulate the mode of functioning of the liquid biofuel market until 2020 are discussed, based on provisions of EU directives. Data on biofuel production in Poland are presented, as well as biofuel consumption in the EU, the USA and Brazil in 2017. The most important conclusions of the proposal for a directive on the promotion of renewable energy sources in transport in EU member states in years 2021–2030 are discussed. The authors have also indicated the key legal and territorial conditions associated with the development of electromobility and present basic information on electric vehicles in Poland and Europe. The results of the research on the attractiveness of these sectors in 2018 are presented and compared with the results obtained in years 2007–2017. A score-based sector attractiveness method was used in the research.
2019
Adam Kupczyk,
Joanna Mączyńska,
Grzegorz Redlarski,
Karol Tucki,
Anna Bączyk,
Dominik Rutkowski
This paper presents results of investigations on a three-dimensional (3-D) isotropic periodic beam. The beam can represent a vibroacoustic isolator of optimised dynamic characteristics in the case of its longitudinal, flexural and torsional behaviour. The optimisation process concerned both the widths as well as the positions of particular frequency band gaps that are present in the frequency spectrum of the beam. Since the dynamic behaviour of the beam is directly related to its geometry, through an optimisation process of the beam geometry, desired dynamic characteristics of the beam were successfully obtained. For the purpose of the optimisation process a new numerical model of the beam, based on the spectral finite element method in the time domain (TD-SFEM), was developed by the authors. This model enabled the authors to investigate the beam behaviour not only in a wide frequency spectrum, but also ensured a high accuracy of the model predictions. The accuracy of this modelling approach was checked against well-known analytical formulas. However, in the case of the optimised geometry of the beam for the verification of the correctness of the modelling approach a commercial finite element method (FEM) package was used. Finally, based on the results of numerical predictions and optimised geometry of the beam a sample for experimental verification was prepared.Experimental measurements were carried out by the authors by the application of one-dimensional (1-D) laser Doppler scanning vibrometry (LDSV). The results of experimental measurements obtained by the authors confirmed the correctness of the numerical predictions, showing a high degree of correspondence.
2019
Arkadiusz Żak,
Marek Krawczuk,
Grzegorz Redlarski,
Łukasz Doliński,
Slawomir Koziel
Smart acoustic band structures exhibit very interesting and non-standard physical properties due to the periodic nature of their certain characteristic on different scale levels. They manifest mostly in their frequency spectra as socalled frequency band-gaps or stop-bands, what has a great impact on the behaviour of these structures in relation to the propagation of vibro-acoustic signals that can be transmitted through the structures in some precisely defined frequency bands. Properties of acoustic band structures are directly linked to their geometry on the level of the unit cell, which parameters determine structural dynamics of such structures on the macroscopic scale. Here the piezoelectric transducers play a significant role. The combined exploitation of active properties of acoustic band structures equipped with active piezoelectric elements, in order to filter or damp transmitted vibro-acoustic signals, allows for very effective their applications. In their paper, the authors present certain results of certain computer simulations by the time-domain spectral finite element method, related to 1-D smart active and passive acoustic band structures supplemented with experimental measurements.
2019
Wiktor Waszkowiak,
Arkadiusz Żak,
Magdalena Palacz,
Marek Krawczuk
The paper presents results of an experimental study related to a non-destructive diagnostic technique used for preliminary determination the location and size of delamination in composite coatings of wind turbine blades. The proposed method of damage detection is based on the analysis of the ten first mode shapes of bending vibrations, which correspond to displacements of rotor blades perpendicular to the rotor plane. Modal parameters depend on the physical properties of the structure. On the other hand, failures can affect these properties (e.g. locally reduce the stiffness of the structure). Monitoring of selected modal parameter can allow determination the technical condition of the structure. The main assumption of the presented method is a comprehensive analysis of the measured data by determination the root mean square value (RMS) for each measurement point from all forms of free vibration obtained from the experiment. As a result, information contained in all modes of vibrations that may indicate damage of the blade will be included in a single characteristic. The investigations were carried out on a scaled-down model of a wind turbine blade of a rotor diameter of 36 m. The modal parameters have been determined only experimentally using a Laser Doppler Scanning Vibrometer. Damage was simulated for three localizations by additional high stiffness elements fixed to the surface of the blade. The results of the research presented in this paper confirm the effectiveness of RMS calculation in detection damage using modes of vibrations.
2019
Łukasz Doliński,
Marek Krawczuk,
Arkadiusz Żak
This paper deals with certain aspects related to the dynamic behaviour of isotropic shell-like structures analysed by the use of a higher order transversely deformable shell-type spectral finite element newly formulated and the approach known as the Time-domain Spectral Finite Element Method (TD-SFEM). Although recently this spectral approach is reported in the literature as a very powerful numerical tool used to solve various wave propagation problems, its properties make it also very well suited to solve static and dynamic modal problems. The robustness and effectiveness of the current spectral approach has been successfully demonstrated by the authors in the case of thin-walled spherical shell structures through a series of numerical tests comprising the analysis of natural frequencies and modes of vibration of an isotropic spherical shell as well as the wave propagation analysis in the case of the same spherical shell and a half-pipe shell-like structure.
2018
Arkadiusz Żak,
Marek Krawczuk
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