102,638 research outputs found
Crack propagation in honeycomb cellular materials: a computational approach
No full textComputational models based on the finite element method and linear or nonlinear fracture mechanics are herein proposed to study the mechanical response of functionally designed cellular components. It is demonstrated that, via a suitable tailoring of the properties of interfaces present in the meso- and micro-structures, the tensile strength can be substantially increased as compared to that of a standard polycrystalline material. Moreover, numerical examples regarding the structural response of these components when subjected to loading conditions typical of cutting operations are provided. As a general trend, the occurrence of tortuous crack paths is highly favorable: stable crack propagation can be achieved in case of critical crack growth, whereas an increased fatigue life can be obtained for a sub-critical crack propagation
Ombra che a me d'intorno, cavatina [from] the opera Gabrielle de Vergi.caraffa, op. 3 /
No full textIn bound volumes: Copyright Deposits 1820-186
Golvanacanthus problematicus Mordvinova & Paruchin, 1978 is a synonym of G. blennii Paggi & Oreccia, 1972 (Acanthocephala, Rhadinorhynchidae)
No full textThe acanthocephalan species Golvanacanthus problematicus Mordvinova & Paruchin, 1978 from the gammarids, Gammarus (Marinogammarus) olivii is considered as a synonym of Golvanacanthus blennii Paggi & Oreccia, 1972 parasitizing in the Black and Mediterranean fish. As our re-study of these species is shown both species don't differ by morphologically.На основе анализа литературных и собственных материалов установлено, что вид Golvanacanthus problematicus Mordvinova & Paruchin, 1978, впервые описанный по акантеллам из черноморских гаммарид, не имеет существенных морфологических отличий от взрослых скребней Golvanacanthus blennii Paggi & Oreccia, 1972, паразитирующих в кишечнике средиземноморских и черноморских рыб. На этом основании G. problematicus сводится в синоним к G. blennii
Corona G., Mannucci E., Petrone L., Balercia G., Paggi F., Fisher A.D., Lotti F., Chiarini V., Forti G., Maggi M.
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Snap-back and snap-through instabilities due to contact loss in the stick-slip motion of rough surfaces
No full textGeneral reliability assessment via the physics-based
No full textThe paper presents a general purpose new methodology, alternative to classical approaches like Montecarlo, FORM and SORM, making use of nominal values and standard deviation values of physical parameters of any physical process. This new assessment methodology has made it possible the creation of a software tool easy to use and able to simulate and manipulate analytically any time dependent and time independent physical process and is able to manage matrixes both with real and complex parameters. Two case studies are shown
Simulation of Experimental Tests in Electronic Devices
No full textA predictive reliability analysis is shown in this paper. Also referring to other previously published articles, based on a mathematical methodology developed by ItalConsul with the collaboration of the University of Rome3, the predictive reliability capacity of the Relysoft software is illustrated. Its task is to perform predictive calculations of the probability of success of any physical process to replace experimental tests with huge savings in time and cost. In this work, the application to a Graetz bridge is illustrated
Reliability of Micromechanical Contact Models: a Still Open Issue
No full textThe assumption of perfectly flat surfaces within the context of the contact problems constitutes very often an oversimplification of the reality. In fact, when real surfaces are examined more in details, roughness can be found at different scale lengths. This fundamental feature poses enormous difficulties on the mathematical modeling of the physics of the contact problems. Nevertheless, the study of the effect of the multiscale roughness on the contact predictions is crucial from the engineering point of view. To deal with this problem several micromechanical contact models have been developed since the middle of the 19th Century. Such models are based on very different mathematical frameworks, with a consequent lack of standardization. The recent perspective to apply such models to smaller and smaller scale lengths, down to the nanoscale, makes the reliability of these models a still open issue. The basic aim of this chapter is to provide a detailed review of the most popular contact models available in the literature. Moreover we focus one the crucial intent of providing a degree of confidence about the differences between the contact predictions provided by the models. For this purpose a critical comparison of the outcomes of such models by applying them to numerically generated rough surfaces is then proposed
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