Search results for " meccanica"

Influence of compliance for an elastokinematic model of a proposed rear suspension

2014

The research is carried out to improve passenger’s comfort to increase the vehicles stability in dynamic conditions. The literature available in the automotive engineering considers different topics for studying suspensions. An example represents mechanisms structure and analysis (synthesis, kinematics, and dynamics) under various operating conditions. These aspects have been approached before analytically, numerical. The current paper studies the influence of the lateral force on the contact patch of the wheel and the corresponding variations of vehicle stability parameters, such as camber angle and wheel rear track. The study is performed for a newer innovative rear suspensions mechanism …

Optimization of the characteristic angles of both front and rear McPherson suspensions on a circular track using multi-body numerical simulation

2009

The research reported in this paper aims to simulate the road-holding of a virtual vehicle using multi-body simulation to estimate both the contact forces between the tyre and ground and the roll motion when cornering. Furthermore, the effect of the characteristic angles on the variation in the forces of the tyre in contact with the ground is studied to determine optimal values for these angles. Emphasis is placed on an average-class vehicle, of which both the external dimensions and mass are chosen appropriately, with a McPherson suspension mounted on both the front and the rear. The characteristic values of the camber and toe-in angles, in both the front and the rear, are optimized for m…

Influence of row orientation on the canopy temperature of Sicilian vineyards

2021

Row orientation can have significant effects on grape quality as it directly affects the exposure of the fruits with indirect consequences on wine quality. In this study, a Flir i7 thermal camera was used to measure the temperature of both canopy sides of a ‘Sauvignon blanc’ vineyard trained to vertical shoot position and with north-south (NS) and east-west (EW) row orientations. Photosynthetically active radiation (PAR) measurements using a 0.8-m sensor bar were taken along with the thermal imaging camera measurements. Considering both row orientations, south and east canopy sides were those that intercepted the greatest radiant energy during the day, 57.7 and 47.5%, respectively. The EW r…

ANALISI DEL COMPORTAMENTO MECCANICO DI SANDWICHES GREEN COSTITUITI DA PELLI IN BIOCOMPOSITO E CORE IN BALSA/SUGHERO

2022

Negli ultimi anni l’aumento della sensibilità nei confronti della salvaguardia ambientale, anche attraverso apposite norme in materia di lotta all’inquinamento e di riciclo dei materiali a fine vita, ha portato ad un notevole interesse dei ricercatori verso i cosiddetti compositi green, materiali costituiti in genere da rinforzi di origine naturale e matrici “bio-based” a basso impatto ambientale. Una categoria interessante di materiali innovativi, caratterizzati da una elevata resistenza a flessione unita ad un basso peso specifico, è rappresentata dai cosiddetti sandwiches, costituiti in genere da robuste pelli in composito fibro-rinforzato e da un core in materiale molto leggero e poco r…

ANALISI E SVILUPPO DI UN SETUP SPERIMENTALE PER LA DETERMINAZIONE DELLA TENACITÀ A FRATTURA A MODO II NEI MATERIALI COMPOSITI E IBRIDI

Il presente lavoro di Tesi si propone a compimento del percorso previsto dal Ciclo XXVI del corso di Dottorato di Ricerca in Ingegneria Civile e Ambientale – Indirizzo Materiali – seguito durante il triennio Gennaio 2013- Dicembre 2015 presso l’Università degli Studi di Palermo. L’elaborato si sviluppa in due principali sezioni. Dopo un’introduzione all’argomento affrontato, nella prima parte del lavoro, viene analizzato, sia sperimentalmente che numericamente, un setup tipicamente utilizzato nell’industria aeronautica per la caratterizzazione delle delaminazione a MODO II nei materiali compositi (Transverse Crack Tensile test – TCT-test). A partire dai risultati ottenuti dalle analisi prel…

TENACITÀ ALLA FRATTURA INTERLAMINARE DI COMPOSITI CFRP SOTTOPOSTI A PROCESSI DI INVECCHIAMENTO IDROTERMICO

2011

In questo lavoro si è condotto uno studio degli effetti dell’invecchiamento idrotermico sulla tenacità alla frattura interlaminare in Modo I di laminati in composito CFRP con lay-up unidirezionale. I pannelli realizzati impiegano una resina epossidica DGEBA. Provini DCB sono stati ricavati in accordo con la norma ASTM D5528. Prove dinamico meccaniche DMTA sono state condotte per analizzare l’influenza dell’invecchiamento sulla temperatura di transizione vetrosa, e quindi sul grado di fragilità della matrice. Il lavoro descrive il set-up sperimentale per la determinazione delle Curve R, evidenziando l’influenza della morfologia del tessuto in carbonio. I valori di GIC di innesco e di propaga…

Analysis of the mechanical performance of hybrid (SPR/bonded) single-lap joints between CFRP panels and aluminum blanks

2013

Abstract The increasing use of innovative materials in manufacturing of modern mechanical components has led to the development of reliable joints between innovative (composite materials etc.) and traditional materials (steel, aluminum etc.). In the last few years, hybrid joints, combining the advantages of the adhesive joints and traditional mechanical joints as bolted or riveted joints, have been shown an increasing industrial interest especially in automotive and aerospace sectors. In the present paper a systematic experimental study of hybrid lap joints was carried out with the aim to detect the optimal joint configuration. Tensile tests on hybrid joints made by combining adhesive bondi…

Numerical-Analytical Model for Nanotube-Reinforced Nanocomposites

2013

A novel numerical model able to predict the elastic properties of carbon nanotube/polymer composites containing a random distribution of CNTs has been developed. The new technique, which takes into account of the curvature that the nanotubes show when immersed in the polymer, is based on a numerical-analytical approach that has significant advances over micromechanical modeling and can be applied to several kinds of nanostructured composites. The nature of carbon nanotube/polymer bonding has arisen as key factor in the efficacy of the carbon nanotubes to actually provide any enhanced stiffness or strength to the composite. Here the effects of carbon nanotube interface interaction with the m…

CADASTRAL MODELS IN EU MEMBER STATES

2019

Abstract Cadastres are always related to land: they are a creation of man as effect of his relationship with land. The different conditions of the Cadastre in 14 EU Member States, including the former EU Candidate States (that nowadays are also EU members), are shown in this paper. Half of EU countries store cadastral and registration data in the same database. Basically two original models of cadastral system exist in the EU, related with systems of land registration : 1) in the Central European model (beyond the area of the Germanic “Grundbuch”) Cadastre emerges as a graphic basis (map) of land registration (Land Registry), so that physical changes must be reflected in the Cadastre and le…

A critical assessment of methods for the determination of the shear stress amplitude in multiaxial fatigue criteria belonging to critical plane class

2015

Abstract Multiaxial high cycle fatigue criteria based on the critical plane approach necessitate unambiguous definitions of the amplitude and mean value of the shear stress (τa and τm) acting on the material planes. Four of the existing definitions relate the values of τa and τm to a geometrical element of the curve described by the tip of the shear stress vector (curve Ψ), respectively, the radius of the Minimum Circumscribed Circle, the Longest Chord, the Longest Projection, the diagonal of the Maximum Rectangular Hull (MRH). In this paper a critical assessment of the above definitions is proposed, focusing on that based on the concept of MRH, which is the most recently developed. The mai…