Search results for " CFRP"

Mechanical Behavior of Steel Fiber-Reinforced Concrete Beams Bonded with External Carbon Fiber Sheets

2017

This study investigates the mechanical behavior of steel fiber-reinforced concrete (SFRC) beams internally reinforced with steel bars and externally bonded with carbon fiber-reinforced polymer (CFRP) sheets fixed by adhesive and hybrid jointing techniques. In particular, attention is paid to the load resistance and failure modes of composite beams. The steel fibers were used to avoiding the rip-off failure of the concrete cover. The CFRP sheets were fixed to the concrete surface by epoxy adhesive as well as combined with various configurations of small-diameter steel pins for mechanical fastening to form a hybrid connection. Such hybrid jointing techniques were found to be particularly adva…

Numerical and Experimental Study of Defects Evolution in a Composites Wing Box Under Compressive Loads

2013

Due to their high specific strength and stiffness, Carbon Fibres Reinforced Plastics (CFRP) are commonly considered suitable for aerospace structural applications. However, their failure mechanisms are not completely predictable and this is the main reason why the CFRP integration in the aerospace industry has been generally slow in the last twenty years. Indeed, the lack of robust numerical tools, able to take into account the damage tolerance of composite structures, has led to over-conservative designs, not fully realising the promised economic benefits of composites materials. The Project MACMES (Damage Management of Aircraft Composite Structures Monitored by Embedded Sensors), funded b…

Debonding Phenomena in CFRP Strengthened Calcarenite Masonry Walls and Vaults

2009

In this paper the results of an experimental investigation on full-scale reinforced masonry elements like vaults and walls are presented. The masonry type is constituted by calcarenite ashlars and bed joint mortar and the reinforcement is constituted by Carbon Fibre Reinforced Polymer (CFRP) strips. Preliminary experimental results obtained in a previous research by the authors on the local behaviour at the interface CFRP-calcarenite are summarized. Tests with controlled displacement are carried out on out-of-plane loaded walls and cylindrical vaults loaded at a quarter of the span. Results of tests carried out before and after the application of the reinforcement made it possible to evalu…

Nonlinear FE analysis of out-of-plane behaviour of masonry walls with and without CFRP reinforcement

2014

Abstract The out-of-plane behaviour of unreinforced and CFRP reinforced masonry wall is studied by means of experimental investigation and numerical FE modelling. The latter is based on a linear constitutive law both for ashlars and mortar joints constituting masonry and the lines of potential delamination are taken into account by means of an interface element with bi-linear law, reproducing the opening failure mode. When reinforcement is introduced, an interface element with bi-linear law is also used, reproducing sliding failure mode. Comparison between numerical and experimental results show the reliability of the modelling. Moreover, a parametric analysis is carried out in order to inv…

Comportamento meccanico di una volta rinforzata con CFRP

2001

Il presente lavoro riguarda il progetto e l'esecuzione di un intervento di rinforzo di una volta a padiglione lunettata di una Villa di interesse storico-monumentale del 700. Tale volta è realizzata con conci di calcarenite inzeppati con cunei di legno e senza malta di connessione, tipologia molto diffusa in tutta l'area del mediterraneo. L’intervento è stato preceduto dallo studio del comportamento meccanico della volta in laboratorio e da prove dinamiche in sito. Particolare attenzione è stata rivolta al sistema di trasmissione dei carichi verticali allo scopo di rendere meno gravoso lo stato tensionale nella parte più alta della volta. Il sistema strutturale è stato analizzato per mezzo …

Sostenibilità di interventi di miglioramento sismico di strutture in c.a. non danneggiate

2012

Analisi quantitativa dell'effetto termoelastico in materiali compositi CFRP

2008

Mode I fracture toughness behaviour of epoxy resincarbon fiber composites cured by ionising radiation

2012

In this work Mode I fracture toughness behavior of Electron Beam cured unidirectional CFRP laminates is investigated by means of standardized Double Cantilever Beam (DCB) tests. A matrix system, comprising a DGEBA epoxy monomer and a typical initiator of cationic polymerization, was used and panel samples assembled by hand lay-up. Curing was achieved by 20 to 40 minutes irradiation on a pulsed 10 MeV Electron Beam accelerator. One batch of resin was also mixed with 10 phr of a PES thermoplastic monomer in order to enhance the matrix toughness. The influence of fibre-matrix adhesion, matrix toughening and matrix crosslinking density on the mode I delamination behavior have been investigated …

Strengthening of masonry walls subjected to out-of-plane loads using CFRPs

2007

This paper presents an experimental investigation carried out on masonry panels subjected to axial load and bending moment in the plane of minor inertia. The masonry type consist of calcarenite ashlars and mortar joints; the reinforcement is made of Carbon Fibres Reinforced Polymer (CFRP) strips applied with the wet-lay-up system. Tests are carried out with controlled displacements. Results have been recorded at each step in terms of: horizontal force and corresponding displacements; moment and curvature at the base of the wall; strains on the CFRP strips near the base of reinforced specimens in order to observe the delamination phenomen. Comparison between the results relative to unreinfor…

Effect of Core–Shell Rubber Nanoparticles on the Mechanical Properties of Epoxy and Epoxy-Based CFRP

2022

This research was funded by M-Era.Net project MERF “Matrix for carbon reinforced epoxy laminates with reduced flammability” grant No. 1.1.1.5/ERANET/20/04 from the Latvian State Education Development Agency and M-Era.Net project “EPIC—European Partnership for Improved Composites“ funded by grant No. TH06020001. A.S., K.S. and A.Z. are grateful to funding received from the European Union Horizon 2020 Framework program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.