numerical evaluation of internal heat generation of roller coaster polyurethane wheels

n/

RECOVERING THE INTRINSIC METALLICITY DISTRIBUTION OF ELLIPTICAL GALAXIES

We address the problem of deriving, from the observed projected metallicity gradients, the intrinsic metallicity distribution of elliptical galaxies as a function of their integrals of motion. The method is illustrated by an application to anisotropic spherical Hernquist models. We also compare the derived metallicity distribution with those expected from two very simple models of galaxy formation and find that the more dissipative scheme agrees better with the typical metallicity distribution of ellipticals.Comment: 3 pages, Postscript file, 1 figure available upon request from [email protected]

sine sweep qualification test for engine components the choice of simulation technique

n/

evaluation of fatigue damage with an energy criterion of simple implementation

Abstract Many theoretical methods for multiaxial fatigue life prediction are present in literature, most of them based on their effectiveness on knowledge of the entire stress time history. This represents the great applicative limit. The incapacity to study real situations, not only deterministic one, let the authors to develop a simple and rigorous criterion, which helps the designer who works in this area. The criterion is presented focusing the attention on the basic premise, highlighting its applicability, its practicality and its computational power. To do that, the Authors take into account the deterministic or random character of the individual constraint components and their degree of correlation. In order to verify the method, simulations of multiaxial loads conditions, developed in the time domain, will be carried out with various correlation levels between the stress components on which the method will be applied

I Santuari di Diomede al Timavo

U Fons Timavi nije se nalazio samo sveti Diomedov gaj, već i tri arhajska otvorena svetišta, od kojih je jedno bilo posvećeno spomenutom junaku, a druga dva dvjema božicama: argivskoj Heri i etolskoj Artemidi.A Fons Timavi non si trovava solo il bosco sacro di Diomede, ma vi erano anche tre santuari a cielo aperto, uno dei quali era dedicato all’eroe già menzionato, e gli altri due alle due dee: a Era Argiva e ad Artemide Etolica

The importance of dynamic behaviour of vibrating systems on the response in case of non-Gaussian random excitations

Abstract Dynamic response of vibrating system subjected to non-Gaussian random loads was investigated through a set of numerical simulation on several lumped systems aimed to determine whether and in what form the dynamic behaviour of a vibrating system transfers or masks non-Gaussianity features of the input to the output response. Indeed, in several numerical and experimental activities performed on a Y-shaped specimen it was observed how the system response, both in terms of displacement or stress, changed according to an input variation (stationary and non-stationary Gaussian and non-Gaussian load time histories) and according to a change of the system frequency response function. Moreover, it was observed that even if the system was excited in its frequency range, the response remains unchanged and similar to the input in case of non-stationary and non-Gaussian load, removing preliminarily the possibility to use spectral methods for damage evaluation, going necessarily back to a more "expensive" time-domain analysis. Since the system response characteristics may change significantly according to the input excitation features and to the dynamic system parameters allowing, in some cases, the use of spectral techniques for fatigue damage evaluation also in case of non-Gaussian input loads, the aim of this paper is to understand whether and how the dynamic behaviour of a generic mechanical system transforms the non-Gaussian input excitations into a Gaussian response. To this aim several numerical displacement responses of 1-dof lumped systems characterized by different frequency response functions (resonance frequency position and damping) were analysed and investigated for different stationary and non-stationary Gaussian and non-Gaussian excitations. In such a way, it was possible to a-priori establish under what circumstances the frequency-domain approaches can be adopted to compute the fatigue damage of real mechanical systems

Dauni in medio Adriatico?

Prima della massiccia penetrazione greca in Adriatico, i Dauni ebbero un posto di rilievo tra le genti che commerciarono in questo mare. Alla documentazione archeologica si affianca, infatti, la memoria storiografica, che attribuisce ai Dainu il controlo su tutta la costa adriatica che si estende dal Gargano al Cònero

correction formula approach to evaluate fatigue damage induced by non gaussian stress state

Abstract In the present paper the authors define an original analytical expression of a corrective coefficient to evaluate fatigue damage induced by a non-Gaussian stress state affected by high Kurtosis (values higher than 5) and by zero Skewness. This approach starts from a previous activity in which the authors solved an analogous problem but for light non-Gaussian stress states (Kurtosis value less than 5). The proposed procedure assumes to know the fatigue damage induced by Gaussian equivalent stress state time domain process. This characteristic allows the proposed procedure to be easily adopted inside the so-called Frequency Domain Fatigue Methods but in parallel with the statistical analysis of the system time domain response (Kurtosis and Skewness evaluation). Interesting considerations about its applicability will be proposed as concerns the non-Gaussianity and non-Stationarity of the inputs when the system is a flexible component excited in its frequency range