Experimental analysis of fiber reinforced cementitious matrix (FRCM) confined masonry columns

The increasing use of Fiber Reinforced methods for strengthening existing brick masonry walls and columns, especially for the rehabilitation of historical buildings, has generated considerable research interest in understanding the failure mechanism in such systems. This dissertation is aimed to provide a basic understanding of the behavior of solid brick masonry walls unwrapped and wrapped with Fiber Reinforced Cementitious Matrix Composites. This is a new type of composite material, commonly known as FRCM, featuring a cementitious inorganic matrix (binder) instead of the more common epoxy one. The influence of the FRCM-reinforcement on the load-carrying capacity and strain distribution during compression test will be investigated using a full-field optical technique known as Digital Image Correlation. Compression test were carried on 6 clay bricks columns and on 7 clay brick walls in three different configuration, casted using bricks scaled respect the first one with a ratio 1:2, in order to determinate the effects of FRCM reinforcement. The goal of the experimental program is to understand how the behavior of brick masonry will be improved by the FRCM-wrapping. The results indicate that there is an arching action zone represented in the form of a parabola with a varying shape according to the used configuration. The area under the parabolas is considered as ineffectively confined. The effectively confined area is assumed to occur within the region where the arching action had been fully developed.

Studio dell’effetto di cicli termici su materiali CFRP (Carbon Fiber Reinforced Polymer) attraverso prove di caratterizzazione statica

L’intento di questa tesi è fornire un andamento di alcune proprietà dei materiali compositi in fibra di carbonio, CFRP, utilizzati soprattutto nell’ambito aeronautico e navale, esposti quindi a condizioni ambientali specifiche di variazione ciclica della temperatura. Lo studio è effettuato sulle prove di caratterizzazione statica, di compressione, flessione in tre punti e taglio interlaminare, che generano risultati sulla resistenza delle fibre e della matrice e sul modulo elastico a compressione e trazione del composito.

Study of the mechanisms of shear transfer in fiber-reinforced concrete elements

matlab functions for the validation of push-off tests results

Utilizzo industriale di cfrp (carbon fiber reinforced polymers) nanomodificati con nanofibre prodotte per elettrospinning

Attraverso questo studio sono state indagate le proprietà di compositi laminati in fibra di carbonio (CFRP) nano-modificati con nanofibre in Nylon 6.6, in termini di resistenza al danneggiamento da impatti a bassa velocità (con caratterizzazione Drop Weight at Low Velocity) e di smorzamento della vibrazione (con caratterizzazione a damping). Sono stati indagate due configurazioni di nanorinforzo differenti, confrontate con le prestazioni di provini vergini laminati tradizionalmente. Sono infine state operate delle analisi grafiche delle micrografie di campioni sezionati per trarre conclusioni di carattere tecnologico.

Implementation of a VLSI amplifier interfaced with biomedical sensors for ultra wide band data transmission

This thesis presents a CMOS Amplifier with High Common Mode rejection designed in UMC 130nm technology. The goal is to achieve a high amplification factor for a wide range of biological signals (with frequencies in the range of 10Hz-1KHz) and to reject the common-mode noise signal. It is here presented a Data Acquisition System, composed of a Delta-Sigma-like Modulator and an antenna, that is the core of a portable low-complexity radio system; the amplifier is designed in order to interface the data acquisition system with a sensor that acquires the electrical signal. The Modulator asynchronously acquires and samples human muscle activity, by sending a Quasi-Digital pattern that encodes the acquired signal. There is only a minor loss of information translating the muscle activity using this pattern, compared to an encoding technique which uses astandard digital signal via Impulse-Radio Ultra-Wide Band (IR-UWB). The biological signals, needed for Electromyographic analysis, have an amplitude of 10-100μV and need to be highly amplified and separated from the overwhelming 50mV common mode noise signal. Various tests of the firmness of the concept are presented, as well the proof that the design works even with different sensors, such as Radiation measurement for Dosimetry studies.

Experimental characterization of carbon-fiber-reinforced polymer laminates

The goal of this thesis is to make static tensile test on four Carbon Fiber Reinforced Polymer laminates, in such a way as to obtain the ultimate tensile strength of these laminates; in particular, the laminates analyzed were produced by Hand Lay-up technology. Testing these laminates we have a reference point on which to compare other laminates and in particular CFRP laminate produced by RTM technology.