Search results for " meccanica"

PROVE COMPARATIVE SULLA RICHIESTA DI ENERGIA NECESSARIA PER L'ESTRAZIONE DELL'OLIO DALLE OLIVE E DALLE SANSE DI LAVORAZIONE

1993

Inverting Multiple Residual Stress Components from Multiple Cuts with the Contour Method

2007

An extension of the contour method is presented which allows the measurement of multiple stress components by making multiple cuts. In the contour method, a body is carefully cut in two using wire electric discharge machining (EDM). The contours, or shapes, of the cut surfaces are then measured and used to calculate the original residual stress normal to the cut plane using a simple finite element calculation. In the extension presented here, the two pieces from the original body can be cut again in a transverse direction, and the contours of the new cut surfaces are measured. The stresses calculated on the planes of these second cuts have been affected by the first cut. Then a simple inver…

Optimising the efficiency of olive harvesting considering operator safety

2019

Mechanical-assisted harvesting of olives, which is carried out using hand-held harvesting units that detach the drupes through vibration supplied by electric motor or combustion engines, is a widespread method used in southern Italy. Such machines are able to harvest more than 80% of the overall quantity of olives available per tree in 5–10 min, but their performance is influenced by several factors related to the mechanical characteristics of the device and to the features of the trees. Here the problem of optimising harvesting efficiency whilst minimising the health risks to the operators is investigated, with the aim of demonstrating that it is possible to determine an optimum harvesting…

Conformable eddy current array delivery

2016

The external surface of stainless steel containers used for the interim storage of nuclear material may be subject to Atmospherically Induced Stress Corrosion Cracking (AISCC). The inspection of such containers poses a significant challenge due to the large quantities involved; therefore, automating the inspection process is of considerable interest. This paper reports upon a proof-of-concept project concerning the automated NDT of a set of test containers containing artificially generated AISCCs. An Eddy current array probe with a conformable padded surface from Eddyfi was used as the NDT sensor and end effector on a KUKA KR5 arc HW robot. A kinematically valid cylindrical raster scan path…

KNOWN RESIDUAL STRESS SPECIMENS USING OPPOSED INDENTATION

2009

In order to test new theories for residual stress measurement or to test the effects of residual stress on fatigue, fracture, and stress corrosion cracking, a known stress test specimen was designed and then fabricated, modeled, and experimentally validated. To provide a unique biaxial stress state, a 60 mm diameter 10 mm thick disk of 316L stainless steel was plastically compressed through the thickness with an opposing 15 mm diameter hard steel indenters in the center of the disk. For validation, the stresses in the specimen were first mapped using time-of-flight neutron diffraction and Rietveld full pattern analysis. Next, the hoop stresses were mapped on a cross section of two disks usi…

Nonlinear analysis of cylindrical and conical hysteretic whirl motions in rotor-dynamics

2014

Abstract The internal friction of a rotor–shaft-support system is mainly due to the shaft structural hysteresis and to some possible shrink-fit release of the assembly. The experimentation points out the destabilizing effect of the internal friction in the over-critical rotor running. Nevertheless, this detrimental influence may be efficiently counterbalanced by other external dissipative sources located in the supports or by a proper anisotropic configuration of the support stiffness. The present analysis considers a rotor–shaft system which is symmetric with respect to the mid-span and is constrained by viscous-flexible supports with different stiffness on two orthogonal planes. The cylin…

Elia Ovazza, Professor of TMM in Palermo Around the End of the 19th Century

2015

In this paper, the figure of Elia Ovazza, professor of TMM in Palermo around the end of the 19th century, is presented, along with his valuable legacy in regard to his activities in teaching, research, design and technology transfer. Short biographical notes outline his foremost life events and an illustrated survey explains his contributions.

Robotic path planning for non-destructive testing of complex shaped surfaces

2015

The requirement to increase inspection speeds for non-destructive testing (NDT) of composite aerospace parts is common to many manufacturers. The prevalence of complex curved surfaces in the industry provides significant motivation for the use of 6 axis robots for deployment of NDT probes in these inspections. A new system for robot deployed ultrasonic inspection of composite aerospace components is presented. The key novelty of the approach is through the accommodation of flexible robotic trajectory planning, coordinated with the NDT data acquisition. Using a flexible approach in MATLAB, the authors have developed a high level custom toolbox that utilizes external control of an industrial …

DETERMINATION AND ANALYSIS OF HEAD AND CHEST PARAMETERS BY SIMULATION OF VEHICLE-TEENAGER IMPACT

2013

This paper reports the results of multi-body numerical simulation of a vehicle crash with a teenager pedestrian. A previous technique utilized for adult pedestrian impact is applied. The work starts with the determination of the masses for the various segments of the body of a teenager with a total mass of 45 kg and then switches to the construction of the dummy and the middle-class vehicle in the Visual Nastran environment. Simulations are performed for both frontal impacts and lateral impacts, when the vehicle is travelling at a constant speed and when the vehicle is braking, following the Euro NCAP rules on the subject. The results are analysed by calculating the values of the head inju…

Assessment of organic waste management methods through energy balance

2014

In Italy, the Organic Fraction of Municipal Solid W aste (OFMSW) is nowadays landfilled or processed through aerobic composting. The Italian towns curre ntly support a high cost for OFMSW disposal and cause a high environmental impact, because of long distance s travelled from towns to a few available landfills and fewer treatment places, as well as the used waste m anagement methods. An interesting option for OFMSW is Anaerobic Digestion (AD), producing biogas and “digestate”. In this survey a theoretical biogas plant was placed near a town of Sicily Region (Italy), centra lised with reference to the area considered for pro ducing OFMSW. The distances travelled every year to transport OFMS…