666 research outputs found
Automatic CAD-FEM procedure for gear analysis
No full textThe interest on gear noise problems is increased remarkably in the last ten years. Variable mesh stiffness, impacts and backlash affect the transmission error, main source of in desiderate noise. The control of gear geometry, as well as the influence of contact ratio and loads, plays a key role in this effort. In the present paper, a CAD-FEM methodology for spur gears is proposed. This tool provides the exact gear geometry, the relative position and the FEM mesh for a wide family of spur gears. The software generates the gear profiles from parameters describing the ‘‘user rack’’. Particular attention is paid on simulating the enveloping process in the presence of protuberance and semi-topping in the cutting tool. The shaving manufacturing process is also taken into account. A parametric approach is developed to generate the FEM mesh according to the teeth profile geometry. Finally a test case is presented to prove the accuracy of the static analysi
Dynamic optimization of spur gears
No full textThis paper presents a global optimization method able to find gear profile modifications that minimize vibrations. A non linear dynamic model is used to study the vibrational behavior; the dynamic model is validated using data available in literature. The optimization method takes into account the influence of torque levels both on the static and the dynamic response. Therefore, two different objective functions are considered; the first one is based on static analysis and the second one is based on the dynamic behavior of a lumped mass system. The procedure can find the optimal profile modification that reduce the vibrations over a wide range of operating conditions. In order to reduce the computational cost, a Random-Simplex optimization algorithm is developed; the optimum reliability is also estimated using a Monte Carlo simulation. The approach shows good performances both for the computational efficiency and the reliability of results
NONLINEAR OSCILLATIONS AND STABILITY OF GEAR PAIR
No full textNonlinear oscilIations of gear pair are analyzed by means of a single-degree-oFfieedompiecewise linear time variant oscillator. The harmonic balance method and a continuationtechnique are used to study periodic motions. The dynamic scenario for an actual gear pair isanalyzed for which concern periodic oscillations
La Vestale 'incesta'
No full textMarcello Salvadore: La Vestale incesta.
Dionysius of Halicarnassus, Pliny the Younger and Plutarch are the sources
of a detailed account of Vestalis incesta’s punishment: they say that she was
sentenced to death. Dionysius adds that there was no after death ritual.
Modern scholars generally accept what the three authors assert. In this article
the author surmises that the Vestalis incesta, together with the parricida, was
not condemned to death: both of them were sentenced to a particular kind
of banishment from the Society
De Lope a Celano: la adaptación italiana de "Los tres diamantes"
No full textAbstract
This paper explores an Italian adaptation of Lope de Vega’s play Los tres diamantes, written in the
second part of the seventeenth century. Its author, Carlo Celano, was a famous writer of opere regie,
i.e., adaptations of Spanish comedies of situation. The analysis focuses on the way in which the
adaptation of the Aristotelian units of space and time leads to a reduction of the characters and a
simplification of the situation, although this is compensated by enriching its ludic component. This
last trait can be also observed in a previous re-elaboration of Lope’s comedy, the scenario of the
Commedia dell’arte titled Il cavaliere dai tre gigli d’oro
Due note critiche
No full textMarcello Garzaniti
Answers to Criticism
The author answers to the critics of M. Capaldo and A.Giambelluca Kossova with the aim to bring the different proposed questions back into the sphere of scientifi c dialogue
Dynamic Optimization of Spur Gears
No full textThis paper presents a global optimization method focused on gear vibration reduction by means of profile modifications. A nonlinear dynamic model is used to study the vibration behavior; such model is validated using data available in literature. The optimization method considers different regimes and torque levels; the objective function can be the static transmission error or the maximum amplitude of the gear vibration in terms of dynamic transmission error. The procedure finds the optimal profile modification that reduces the vibrations over a wide range of operating conditions. In order to reduce the computational cost, a Random–Simplex optimization algorithm is developed; the optimum reliability is estimated using a Monte Carlo simulation. The approach shows good performances for the computational efficiency as well as the reliability of results. Finally, an application to High Contact Ratio (HCR) gears is presented and an extremely good performance is obtained by combining optimization procedures and HCR properties
The Pragmatics of Literature
No full textThis translation of the work of one of the founding fathers of literary structuralism and semiotics in Italy is a timely introduction to the theoretical study of literary communication. Marcello Pagnini is a leading figure in the post-structuralist endeavor to return the text to something resembling its social matrix. He explores not only the dynamics of the author/reader rapport but also the connections between the literary text and its sociocultural and historical contexts
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