Development of Urban Electric Bus Drivetrain

The development of the drivetrain for a new series of urban electric buses is presented in the paper. The traction and design properties of several drive variants are compared. The efficiency of the drive was tested using simulation calculations of the vehicle rides based on data from real bus lines in Prague. The results of the design work and simulation calculations are presented in the paper

A micromechanics-enhanced finite element formulation for modelling heterogeneous materials

In the analysis of composite materials with heterogeneous microstructures, full resolution of the heterogeneities using classical numerical approaches can be computationally prohibitive. This paper presents a micromechanics-enhanced finite element formulation that accurately captures the mechanical behaviour of heterogeneous materials in a computationally efficient manner. The strategy exploits analytical solutions derived by Eshelby for ellipsoidal inclusions in order to determine the mechanical perturbation fields as a result of the underlying heterogeneities. Approximation functions for these perturbation fields are then incorporated into a finite element formulation to augment those of the macroscopic fields. A significant feature of this approach is that the finite element mesh does not explicitly resolve the heterogeneities and that no additional degrees of freedom are introduced. In this paper, hybrid-Trefftz stress finite elements are utilised and performance of the proposed formulation is demonstrated with numerical examples. The method is restricted here to elastic particulate composites with ellipsoidal inclusions but it has been designed to be extensible to a wider class of materials comprising arbitrary shaped inclusions.Comment: 28 pages, 12 figures, 2 table

Analysis of Phase Evaluation Algorithms in an Interferometric Method for Static Deformation Measurement

This article describes and analyses an interferometric method for measuring displacements and deformation. The method can be used for a very accurate evaluation of the change in the surface shape of structures used in industry. The paper proposes several multistep phase calculation algorithms and describes an automatic evaluation process using the measurement technique. A complex analysis is also performed of various factors that can have a negative effect on the practical measurement and evaluation process. An analysis is made of the proposed multistep phase calculation algorithms using the proposed error model. It is shown that the resulting phase measurement errors can be effectively reduced by using suitable phase calculation algorithms. The analysis can be applied for a complex comparison of the accuracy and stability of such algorithms

New Phase Shifting Algorithms Insensitive to Linear Phase Shift Errors

This article describes and analyses multistep algorithms for evaluating of the wave field phase in interferometric measurements using the phase shifting technique. New phase shifting algorithms are proposed, with a constant but arbitrary phase shift between captured frames of the intensity of the interference field. The phase evaluation process then does not depend on linear phase shift errors. A big advantage of the described algorithms is their ability to determine the phase shift value at every point of the detector plane. A detailed analysis of these algorithms with respect to main factors that affect interferometric measurements is then carried out. The dependency of these algorithms on phase shift values is also studied several phase calculation algorithms are proposed. These are compared with respect to the resulting phase errors

New data on the pseudoscorpion family Chthoniidae (Arachnida: Pseudoscorpiones) from Hungary

Chthonius submontanus Beier, 1963, Ephippiochthonius romanicus (Beier, 1935) and Occidenchthonius parmensis (Beier, 1963) are firstly recorded from Hungary. The genus Occidenchthonius Zaragoza, 2017 is new for the country. A brief description and the relative figures are reported for each species. Fifty-seven species are currently recorded from Hungary