Search results for " costruzione"
showing 10 items of 481 documents
Lock-In Signal Post-Processing Techniques in Infra-Red Thermography for Materials Structural Evaluation
2013
This paper describes the potential of off-line thermographic signal processing by means of Lock-In Correlation algorithms, in order to implement structural health monitoring and stress analysis techniques. Thermal datasets acquired by infrared thermocameras are locked-in and correlated numerically with opportune reference signals, and amplitude and phase values of various harmonics retrieved by means of a Fast Fourier Transform and time averaging based filtering. This information is then processed for NDT defect probing and for evaluating the Thermoelastic Effect induced temperature changes. Two case studies in particular are discussed, implementing the proposed signal lock-in processing: a…
Quantitative thermoelastic stress analysis by means of low-cost setups
2020
Abstract A low-cost Thermoelastic Stress Analysis (TSA) experimental setup is proposed which uses an ordinary micro-bolometer and in-house developed signal processing scripts. The setup is evaluated by analysing the thermoelastic signal from a tensile and a SENT specimen made of stainless steel AISI 304L, and the bolometer performances are compared with those of a state of the art photon detector. Signal processing is based on off-line cross-correlation, using a self-reference signal which is retrieved from the acquired thermal data. Procedures are in particular developed to recognise, quantify and correct errors due to spectral leakage and loss of streamed frames. The thermoelastic signal …
Active magnetic bearing design study
2012
The purpose of this paper is to propose a useful method to implement active magnetic bearings (AMBs) on an existing rotating shaft which rotates on conventional bearings. This is feasible if AMBs can produce the same reaction loads of conventional ones and if the size of vane is large enough to host an AMB. As this substitution could offer some difficulties due to the different size between magnetic bearings and conventional ones, a set of equations are performed to show that a variation of some parameters can solve this problem. The journal ratio is the geometrical parameter introduced to develop the present analysis. The variation of journal ratio does not produce a variation of the pole…
Measuring Multiple Residual-Stress Components using the Contour Method and Multiple Cuts
2009
The conventional contour method determines one component of residual stress over the cross section of a part. The part is cut into two, the contour (topographic shape) of the exposed surface is measured, and Bueckner’s superposition principle is analytically applied to calculate stresses. In this paper, the contour method is extended to the measurement of multiple residual-stress components by making multiple cuts with subsequent applications of superposition. The theory and limitations are described. The theory is experimentally tested on a 316L stainless steel disk with residual stresses induced by plastically indenting the central portion of the disk. The multiple-cut contour method resu…
Investigation on the influence of the surface resin rich layer on the thermoelastic signal from different composite laminate lay-ups
2006
This work presents a set of experimental results based on the measured thermoelastic signal from GRP composite coupons adopting different lay-ups. A comparison is made with the thermoelastic signal predicted by two different analytical models: one based on the classical law of the thermoelastic effect for orthotropic materials, and the other based on a novel theory accounting for the presence of a resin layer on the external surface of the composite structure. The composite coupons were designed such to determine a significant difference in the predictions made by the two theoretical models. Experimental results have shown a far better match with the predictions based on the novel theory ac…
LA FABBRICA DEL TEATRO MASSIMO
2013
Sommario. In queste note, esito dell’analisi diretta del monumento e dello studio delle carte originali del cantiere, si ripercorrono i principali aspetti della costruzione del teatro Massimo V.E. di Palermo, dai temi di valenza urbana a quelli più strettamente tecnici. Si esaminano le rilevanti questioni che attengono alle strutture murarie in fondazione che dovettero tenere conto delle stratificazioni storiche del sito, ma soprattutto in elevazione dove si dovettero contemperare le esigenze tecnico-statiche, di decoro e di economia. Specifica trattazione hanno le strutture metalliche negli orizzontamenti e nelle grandi coperture, con riferimenti puntuali allargati alla tumultuosa innovazi…
Il Teatro “Garibaldi” a Palermo e la costruzione dei teatri storici minori
2013
Degli oltre mille teatri italiani censiti negli anni immediatamente successivi all’Unità, a cui se ne aggiunsero molti altri edificati in seguito, ben pochi permangono a testimoniare i caratteri e la diffusione capillare del teatro all’italiana, dai pochi casi magniloquenti ai più comuni, caratterizzati spesso da connotati di provvisorietà ed occasionalità. Il teatro all’italiana, concepito come raffigurazione di uno spazio urbanistico, riproponeva - in forme e modi costruttivamente analoghi - ciò che da sempre si era realizzato nelle piazze e nei luoghi di incontro all’aperto. L’involucro perimetrale in muratura e la copertura erano realizzati secondo la tradizione costruttiva codificata; …
Investigation of the Thermomechanical Response of Cyclically Loaded NiTi Alloys by Means of Temperature Frequency Domain Analyses
2021
Nickel–Titanium (NiTi) shape memory alloys subjected to cyclic loading exhibit reversible temperature changes whose modulation is correlated with the applied load. This reveals the presence of reversible thermomechanical heat sources activated by the applied stresses. One such source is the elastocaloric effect, accounting for the latent heat of Austenite–Martensite phase transformation. It is, however, observed that when the amplitude of cyclic loads is not sufficient to activate or further propagate this phase transformation, the material still exhibits a strong cyclic temperature modulation. The present work investigates the thermomechanical behaviour of NiTi under such low-amplitude cyc…
COSTRUIRE IN PIETRA FRA INNOVAZIONE E TRADIZIONE
2007
Il Poster illustra la ricerca sulla "pietra di Bagheria", l'antica estrazione della pietra e le cave storiche.
On the correlation of temperature harmonic content with energy dissipation in C45 steel samples under fatigue loading
2022
Fatigue damage onset involves a transformation of mechanical energy. This is in part spent into work of plastic deformation and fracture and in part transformed into heat. Therefore, different thermomechanical heat sources are activated during a fatigue loading cycle, resulting in a temperature modulation that can be characterized by its frequency content. Several studies have monitored the temperature on samples undergoing high-cycle fatigue, measuring specific thermomechanical metrics which could serve as indicators of damage evolution. The present work evaluates the harmonic content of temperature, to investigate its correlation with the material dissipation. The harmonic terms investiga…