A Numerical Modelling Approach for Time-Dependent Deformation of Hot Forming Tools under the Creep-Fatigue Regime

The present study was aimed at predicting the time-dependent deformation of tools used in hot forming applications subjected to the creep-fatigue regime. An excessive accumulated plastic deformation is configured as one of the three main causes of premature failure of tools in these critical applications and it is accumulated cycle by cycle without evident marks leading to noncompliant products. With the aim of predicting this accumulated deformation, a novel procedure was developed, presented, and applied to the extrusion process as an example. A time-hardening primary creep law was used and novel regression equations for the law's coefficients were developed to account not only for the induced stress-temperature state but also for the dwell-time value, which is determined by the selected set of process parameters and die design. The procedure was validated against experimental data both on a small-scale extrusion die at different stress, temperature, load states, and for different geometries and on an industrial extrusion die which was discarded due to the excessive plastic deformation after 64 cycles. A numerical-experimental good agreement was achieved

Experimental assessment of hot-work tool steels performances under the creep-fatigue regime

In the present research an innovative testing method, specifially developed to characterize the tool steels under creep-fatigue conditions, was carried out an a TQ1 hot-work tool steel. The experimental campaign consisted of different testing conditions and part of the specimens were nitrided to account for the specific surface state of the tools. Tests were performed on a 10tons MTS fatigue machine equipped with a heating furnace. A creep-fatigue loading type was applied to the specimens, i.e. a cyclic load with a dwell-time, in order to properly reproduce the conditions acting on a hot forging or extrusion tool. Then, under a constant temperature of 520°C, the effects of four different load levels and 2 different values of dwell-times were evaluated. In addition, selected test conditions were replicated with the specimens not nitrided with the aim to evalute and quantify the influence of the superficial treatment. Final results were presented in terms of fatigue curves of the TQ1 and compared to the performances of the H11 tool steel tested in a previous research by the same authors

Paradiso : spettacolo di danza del gruppo nanou

Obra ressenyada: Gruppo NANOU, Paradiso : spettacolo di danza del gruppo nanou. Ravenna: Ravenna Festival (17 giugno - 2 luglio), 2022

Towards the viewer. Contexts, poetics, studies and shows around the theater that writes with the reality 2000/2019

Il lavoro indaga gli studi sulla relazione teatrale e la mutazione delle poetiche del teatro degli ultimi venti anni in ambito italiano e internazionale. In particolare, si attraversano teorie e poetiche in un’ottica interdisciplinare in cerca dei fondamenti della relazione fra attore e spettatore e tenendo conto della “mutazione socio-antropologica” della società in rete degli ultimi decenni. La tesi studia le poetiche dello spettatore proposte dai maestri del Novecento, riattraversa alcune prospettive di studio sulla relazione teatrale in ottica neo-teatrologica (semiotica, antropologia, sociologia, neuroscienze), definisce il concetto di "scrittura con la realtà" e si concentra infine su alcuni spettacoli, quattordici casi di studio analizzati estesamente che manifestano i segni di una mutazione linguistica: formati spettacolari ibridi, nei quali si ripensano gli elementi del teatro, dalla demarcazione fra attore e personaggio all’istanza ordinatrice della regia fino al valore di stabilizzazione della drammaturgia. Nelle conclusioni si enucleano gli elementi della "scrittura con la realtà", proponendo di leggere le mutazioni del linguaggio teatrale degli ultimi anni come uno spostamento verso una "committenza sociale" della comunità.The work investigates the studies on the theatrical relationship and the mutation of the poetics of the theater of the last twenty years in the Italian and international context. In particular, theories and poetics are crossed in an interdisciplinary perspective in search of the foundations of the relationship between actor and spectator and taking into account the "socio-anthropological mutation" of the so called network society of recent decades. The phd thesis studies the "spectator's poetics" proposed by the masters of the twentieth century, retraces some study perspectives on the theatrical relationship from a neo-theatrological perspective (semiotics, anthropology, sociology, neuroscience), defines the concept of "writing with reality" and finally focuses on some shows, fourteen extensively analyzed case studies that show the signs of a linguistic mutation: hybrid spectacular formats, in which the elements of the theater are rethought, from the demarcation between actor and character to the ordering authority of direction up to the stabilization value of the dramaturgy. The conclusions highlight the elements of "writing with reality", proposing to read the changes in the theatrical language of recent years as a shift towards a "social commission" of the community

Effect of Thermal Ageing on the Mechanical Strength of Carbon Fibre Reinforced Epoxy Composites

Applications of Carbon Fibre Reinforced Polymers (CFRP) at temperatures over 150–200 ◦C are becoming common in aerospace and automotive applications. Exposure of CFRP to these temperatures can lead to permanent changes in their mechanical properties. In this work, we investigated the effect of thermal ageing in air on the strength of carbon fabric/epoxy composites. To this end, accelerated artificial ageing at different temperatures was performed on carbon fabric/epoxy specimens. The flexural and interlaminar shear strengths of the aged specimens were assessed by three-point bending and short beam shear tests, respectively, and compared to those of unaged samples. For ageing at temperatures below the glass transition temperature of the resin, Tg, a moderate reduction of strength was found, with a maximum decrease of 25% for 2160 h at 75% Tg. On the other hand, a rapid strength decrease was observed for ageing temperatures above Tg. This was attributed to degradation of the epoxy matrix and of the fibre/epoxy interface. In particular, a 30% strength decrease was found for less than 6 h at 145% Tg. Therefore, it was concluded that even a short exposure to operating temperatures above Tg could substantially impair the load-carrying capability of CFRP components

Efficiency of Conformal Cooling Channels Inserts for Extrusion Dies

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Improving agricultural drone localization using georeferenced low-complexity maps

To properly locate and operate autonomous vehicles for in-field tasks, the knowledge of their instantaneous position needs to be combined with an accurate spatial description of their environment. In agricultural fields, when operating inside the crops, GPS data are not reliable nor always available, therefore high-precision maps are difficult to be obtained and exploited for in-field operations. Recently, low-complexity, georeferenced 3D maps have been proposed to reduce their computationally demand without losing relevant crop shape information. In this paper, we propose an innovative approach based on the ellipsoid method that allows us to fuse the data collected by ultrasonic sensors and the information provided by the simplified map to improve the location estimation of an unmanned ground vehicle within crops. Then, this improved estimation of the vehicle location can be integrated with orientation data, merging it with those provided by other sensors as GPS and IMU, using classical filtering schemes

3D Distance Filter for the Autonomous Navigation of UAVs in Agricultural Scenarios

In precision agriculture, remote sensing is an essential phase in assessing crop status and variability when considering both the spatial and the temporal dimensions. To this aim, the use of unmanned aerial vehicles (UAVs) is growing in popularity, allowing for the autonomous performance of a variety of in-field tasks which are not limited to scouting or monitoring. To enable autonomous navigation, however, a crucial capability lies in accurately locating the vehicle within the surrounding environment. This task becomes challenging in agricultural scenarios where the crops and/or the adopted trellis systems can negatively affect GPS signal reception and localisation reliability. A viable solution to this problem can be the exploitation of high-accuracy 3D maps, which provide important data regarding crop morphology, as an additional input of the UAVs’ localisation system. However, the management of such big data may be difficult in real-time applications. In this paper, an innovative 3D sensor fusion approach is proposed, which combines the data provided by onboard proprioceptive (i.e., GPS and IMU) and exteroceptive (i.e., ultrasound) sensors with the information provided by a georeferenced 3D low-complexity map. In particular, the parallel-cuts ellipsoid method is used to merge the data from the distance sensors and the 3D map. Then, the improved estimation of the UAV location is fused with the data provided by the GPS and IMU sensors, using a Kalman-based filtering scheme. The simulation results prove the efficacy of the proposed navigation approach when applied to a quadrotor that autonomously navigates between vine rows