Search results for "CFR"
showing 10 items of 32 documents
Experimental Determination of Liquefied Petroleum Gas–Gasoline Mixtures Knock Resistance
2014
The results of previous experimental researches showed that great advantages can be achieved, both in terms of fuel consumption and pollutant emissions, in bifuel vehicles by means of the double-fuel combustion, i.e., the simultaneous combustion of gasoline and a gaseous fuel, such as liquefied petroleum gas (LPG) or natural gas (NG). The substantial increase in knock resistance pursued by adding LPG to gasoline, which allowed to maintain an overall stoichiometric proportion with air also at full load, is not documented in the scientific literature and induced the authors to perform a proper experimental campaign. The motor octane number (MON) of LPG–gasoline mixtures has been hence determi…
Octane Rating of Natural Gas-Gasoline Mixtures on CFR Engine
2014
In the last years new and stricter pollutant emission regulations together with raised cost of conventional fuels resulted in an increased use of gaseous fuels, such as Natural Gas (NG) or Liquefied Petroleum Gas (LPG), for passenger vehicles. Bi-fuel engines represent a transition phase product, allowing to run either with gasoline or with gas, and for this reason are equipped with two separate injection systems. When operating at high loads with gasoline, however, these engines require rich mixtures and retarded combustions in order to prevent from dangerous knocking phenomena: this causes high hydrocarbon (HC) and carbon monoxide (CO) emissions together with high fuel consumption. With t…
Drilling characteristics and properties analysis of fiber reinforced polymer composites: A comprehensive review
2023
Fiber-reinforced polymer (FRP) composites play a vital role in the production of structural and semi-structural components for engineering applications. The drilling process is a commonly employed machining process for FRP composites to join the FRP structural elements. Usually, the FRP composites possess a heterogeneous nature because of their multi-layered structure, hybridization, and the presence of multi-phase materials. Hence, common problems like delaminations, fuzzing, buckling, cracking, matrix and fiber burning occur during the drilling operations. These problems cause dimensional inaccuracy, poor surface finish, and tool wear and reduce the mechanical strength of the composites. …
Ultrasonic inspection for the detection of debonding in CFRP-reinforced concrete
2017
Fibre-reinforced plastic (FRP) composites are extensively used to retrofit civil structures. However, the quality and the characteristics of the bond between the FRP and the structure are critical to ensure the efficacy of the retrofit. For this reason, effective non-destructive evaluation (NDE) methods are often necessary to assess the bonding conditions. This article presents an ultrasonic technique for detecting defects at the FRP-substrate interface. The technique uses the Akaike Information Criterion, to detect automatically the onset of the ultrasonic signals, and the novel Equivalent Time Lenght (ETL) parameter, to quantify the energy of the propagating ultrasonic signals along the i…
Effects of Nylon 6,6 Nanofibrous Mats on Thermal Properties and Delamination Behavior of High Performance CFRP Laminates
2014
none 8 no Nylon 6,6 electrospun nanofibrous membranes interleaved in Carbon Fibre Reinforced Plastic (CFRP) laminates have been proposed as a means to provide a higher threshold value to delamination on structural sites where composites are more prone to develop such failure. A model, highly crosslinked thus inherently brittle, epoxy matrix was selected for its high Young’s modulus and glass transition temperature exceeding 250 °C. The influence of the Nylon 6,6 nanofibres on the curing behaviour of the matrix and on the thermal and dynamic mechanical properties of the cured resin was investigated. These properties were related to the features of the epoxy resin and of the resin impregnated…
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…
Flexural behaviour of concrete corbels containing steel fibers or wrapped with FRP sheets
2005
In the present paper an analytical and experimental investigation referring to the flexural behaviour of reinforced concrete corbels subjected to vertical forces is presented. For fixed shape and dimensions of the corbels the experimental investigation analyses the effects of the following: longitudinal and transverse steel reinforcements; fiber reinforced concrete (FRC) with hooked steel fibers; external wrapping retrofitting technique with a thin layer of carbon fiber sheet (CFRP). The analytical model based on equivalent truss structures, allows one to determine the bearing capacity of corbels, distinguishing the different ultimate states reached. The analytical results are then compared…
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 …