Analysis of the Impact and Mechanical Properties of a Damper Made of Hyperelastic Material

The analysis of mechanical properties in the proposed model of the vibration damping element through the use of a layer of hyperelastic material was presented in the paper. The aim of the study was to analyse the behaviour of the structure under the influence of external forcing forces with the use of hyperelastic materials, which are characterized by high compressive fatigue strength. The model in its construction assumes the use of rubber as a material that acts as a vibration damper. The results presented in the paper include the stress-strain relationship and the vibration analyses. The paper contains the conclusions of the comparative analysis in relation to the reference model. The studies were performed using the finite element method using the ANSYS program. Mesh elements were adopted as 3D solid elements, adapted to the model, and properly densified in the places of contact of individual layers in the model. The Mooney-Rivlin material model, in order to analyze the middle layers, was adopted in the work

Analysis of Forced Vibration Damping With the Use of Hyperplastic Materials

A solution of forced vibration damping through the use of hyperelastic materials have been proposed in the paper. Most structures can be easily simulated on the basis of a linear elastic material model. However, when linear elasticity ceases to be sufficient, then nonlinear models are adopted, e.g. hyperelastic materials. The aim of this study was to investigate the behavior of the structure under the influence of external forces with the use of materials showing high fatigue resistance to compression with simultaneous consideration of vibration damping. The model presented in the paper has been subjected to an excitation in form of displacement. The paper presents a dynamic analysis using the finite element method in the ANSYS program. The comparison concerned the use of hyperelastic materials with the use of the deformation energy model of hyperelastic incompressible materials according to the Mooney-Rivlin model

The COS Legacy Archive Spectroscopy SurveY (CLASSY) Treasury Atlas

Far-ultraviolet (FUV; ~1200-2000 angstroms) spectra are fundamental to our understanding of star-forming galaxies, providing a unique window on massive stellar populations, chemical evolution, feedback processes, and reionization. The launch of JWST will soon usher in a new era, pushing the UV spectroscopic frontier to higher redshifts than ever before, however, its success hinges on a comprehensive understanding of the massive star populations and gas conditions that power the observed UV spectral features. This requires a level of detail that is only possible with a combination of ample wavelength coverage, signal-to-noise, spectral-resolution, and sample diversity that has not yet been achieved by any FUV spectral database. We present the COS Legacy Spectroscopic SurveY (CLASSY) treasury and its first high level science product, the CLASSY atlas. CLASSY builds on the HST archive to construct the first high-quality (S/N_1500 >~ 5/resel), high-resolution (R~15,000) FUV spectral database of 45 nearby (0.002 < z < 0.182) star-forming galaxies. The CLASSY atlas, available to the public via the CLASSY website, is the result of optimally extracting and coadding 170 archival+new spectra from 312 orbits of HST observations. The CLASSY sample covers a broad range of properties including stellar mass (6.2 < logM_star(M_sol) < 10.1), star formation rate (-2.0 < log SFR (M_sol/yr) < +1.6), direct gas-phase metallicity (7.0 < 12+log(O/H) < 8.8), ionization (0.5 < O_32 < 38.0), reddening (0.02 < E(B-V < 0.67), and nebular density (10 < n_e (cm^-3) < 1120). CLASSY is biased to UV-bright star-forming galaxies, resulting in a sample that is consistent with z~0 mass-metallicity relationship, but is offset to higher SFRs by roughly 2 dex, similar to z >~2 galaxies. This unique set of properties makes the CLASSY atlas the benchmark training set for star-forming galaxies across cosmic time.Comment: Accepted for publication in Ap

Optymalizacja stalowej belki wspornikowej z użyciem oprogramowania ANSYS

The problem of analysing complex steel structures in relation to analytical and numerical tests of a single structure element has been presented. The aim was t o demonstrate the compliance of the chosen methods for determining the strength parameters of a cantilever beam and to select the best cross-section for the optimization of the structure. The beam deflection and the value of the maximum reduced stresses (according to Huber von Mises’ hypothesis) have been determined numerically and analytically. Numerical analysis, on the basis of the finite element method, as well as the optimization, have been performed in the ANSYS environment. Based on the static analysis of the structure, optimization of the beam mass has been made by changing its cross-section dimensions, taking into account the specific optimization criteria, pointed in the work. As a result of optimization, solutions satisfying the required criteria have been selected. The weight of the structure has been reduced by half compared to the initial values of the designed structure. The permissible stresses have not been exceeded.Przedstawiono problem analizy złożonych konstrukcji stalowych w odniesieniu do badań analitycznych i numerycznych pojedynczego elementu konstrukcji. Celem było wykazanie zgodności obranych metod wyznaczania parametrów wytrzymałościowych belki wspornikowej oraz dobranie najlepszego przekroju poprzecznego w optymalizacji konstrukcji. Analitycznie oraz numerycznie wyznaczono strzałkę ugięcia belki oraz wartość maksymalnych naprężeń zredukowanych (wg Hubera von Misesa). Analizę numeryczną, z użyciem metody elementów skończonych, oraz optymalizację przeprowadzono w środowisku ANSYS. Na podstawie analizy statycznej konstrukcji przeprowadzono optymalizację masy belki poprzez zmianę jej wymiarów przekroju poprzecznego, przy uwzględnieniu wskazanych w pracy kryteriów optymalizacyjnych. W wyniku optymalizacji zostały wybrane rozwiązania spełniające wymagane kryteria. Masa konstrukcji została zmniejszona o połowę w porównaniu do wartości początkowych projektowanej konstrukcji. Dopuszczalne naprężenia nie zostały przekroczone

Dynamics of the mobile platform with four wheel drive

The dynamics problem of motion of the mobile platform with four wheel drive under the unsteady conditions have been formulated and analysed. The mobile platform prototype have been equipped with four independently driven and steered electric drive units.The theoretical model have been formed for the proposed design concept of the platform. The relations between friction forces in longitudinal and transverse directions in reference to the active forces have been considered. The analysis of the motion parameters for different configurations of the wheel positions has been included. The formulated initial problem has been numerically solved by using the Runge-Kutta method of the fourth order. The sample simulation results for different configurations of the platform elements during its motion have been included and the conclusions have been formulated

Experimental studies and modeling of four-wheeled mobile robot motion taking into account wheel slippage

In the article the results of simulation and experimental studies of the movement of a four-wheeled mobile platform, taking into account wheel slip have been presented. The simulation results have been based on the dynamics of the four-wheel mobile platform. The dynamic model of the system motion takes into account the relationship between the active and passive forces accompanying the platform motion, especially during wheel slip. The formulated initial problem describing the motion of the system has been solved by the Runge-Kutta method of the fourth order. The proposed computational model including the platform dynamics model has been verified in experimental studies using the LEO Rover robot. The motion parameters obtained on the basis of the adopted computational model in the form of trajectories, velocities and accelerations have been compared with the results of experimental tests, and the results of this comparison have been included in the paper. The proposed computational model can be useful in various situations, e.g., real-time control, where models with a high degree of complexity are useless due to the computation time. The simulation results obtained on the basis of the proposed model are sufficiently compatible with the results of experimental tests of motion parameters obtained for the selected type of mobile robot

Analysis of motion of the three wheeled mobile platform

The work is dedicated to the designing motion of the three wheeled mobile platform under the unsteady conditions. In this paper the results of the analysis based on the dynamics model of the three wheeled mobile robot, with two rear wheels and one front wheel has been included The prototype has been developed by the author's construction assumptions that is useful to realize the motion of the platform in a various configurations of wheel drives, including control of the active forces and the direction of their settings while driving. Friction forces, in longitudinal and in the transverse directions, are considered in the proposed model. Relation between friction and active forces are also included. The motion parameters of the mobile platform has been determined by adopting classical approach of mechanics. The formulated initial problem of platform motion has been solved numerically using the Runge-Kutta method of the fourth order. Results of motion analysis with motion parameters values are determined and sample results are presented

Modeling of selected load-bearing structures using the truss and beam elements

The article presents the methodology of adjusting the usable properties of rodlike and beam elements for modeling the complex load-bearing structures. The basic object of consideration was the single-row slewing ball bearing. In this paper the mapping issues of usable qualities of the slewing bearings are summarized in relation to use of the finite element method. The emphasis is primarily on using the rod-like and beam elements for modeling the contact phenomena in the ball-raceway contact zone. In addition, ideas for use of the beam elements to modeling bearing bolts were presented

Mechanical vibrations: recent trends and engineering applications

Although the study of oscillatory motion has a long history, going back four centuries, it is still an active subject of scientific research. In this review paper prospective research directions in the field of mechanical vibrations were pointed out. Four groups of important issues in which advanced research is conducted were discussed. The first are energy harvester devices, thanks to which we can obtain or save significant amounts of energy, and thus reduce the amount of greenhouse gases. The next discussed issue helps in the design of structures using vibrations and describes the algorithms that allow to identify and search for optimal parameters for the devices being developed. The next section describes vibration in multi-body systems and modal analysis, which are key to understanding the phenomena in vibrating machines. The last part describes the properties of granulated materials from which modern, intelligent vacuum-packed particles are made. They are used, for example, as intelligent vibration damping devices.Web of Science701art. no. e14035