1,720,970 research outputs found
"Comportamento a flessione di elementi strutturali in vetro e acciaio"
No full textL’acciaio opportunamente usato nell’accoppiamento con il vetro permette di superare il problema della fragilità del vetro, ne migliora il comportamento flessionale e ne incrementa la resistenza.
Sono state studiate due tipologie di elementi compositi: la prima è costituita da una lastra in vetro rinforzata con fibra d’acciaio, la seconda è una trave composta da lamine di vetro disposte verticalmente e rinforzata all’intradosso da un profilo in acciaio. Per testare il comportamento flessionale, entrambi gli elementi sono stati sottoposti a prove di flessione su 4 punti. I risultati ottenuti sono stati soddisfacenti ed è stato possibile confrontarli con quelli di una precedente sperimentazione su elementi strutturali rinforzati con nastri di fibra di vetro, di carbonio e d’acciaio e con profili pultrus
Travi in legno rinforzate con fibre naturali
No full textIl lavoro mostra i risultati di una sperimentazione riguardante travi rinforzate con fibre naturali di basalto, lino e canapa. La prima fase è stata rivolta alla caratterizzazione meccanica dei materiali impiegati e alle prove di taglio per trazione dell’incollaggio e di adesione per pool-out al fine di testare l’efficacia dell’adesione ed orientare alla scelta della resina. Nella seconda fase della sperimentazione è stato studiato il comportamento strutturale delle travi rinforzate attraverso prove di flessione su quattro punti. Allo scopo sono state realizzate due serie di travi in legno rinforzate con le fibre naturali che si diversificano per la dimensione della trave oltre che per la tipologia della fibra. I risultati ottenuti sono stati soddisfacenti: le travi rinforzate hanno mostrato resistenza e rigidezza superiori a quelle senza rinforzo ed un buon comportamento anche nei confronti di travi rinforzate con le tradizionali fibre di carbonio o vetro
Post-cracking Behaviour of Reinforced Glass Beams
No full textThe study of the structural behaviour of some particular glass beams is presented. An experimental investigation was performed on glass beams reinforced with GFRP sheets and pultruded profiles. Tested beams are formed by float glass sheet glued between them and with the reinforcement using common structural resins. To evaluate the influence of the reinforcement, other series of beams were constructed coupling glass and steel fibres or glass and steel profile. The aim was to increase tensile resistance and solve the problem of the brightly of the glass and the great dispersion of the tensile strength values. In all the experiments the beams showed residual resistance and a great value of the ratio between final failure displacement and initial failure displacement which is indicative of a ductile behaviour. The behaviour of these beams was studied developing analytical models and numerical models which describe the elastic phase and the post-cracking phase too
Experimental Performance of Glass Beams
No full textThe study of the structural behaviour of some particular glass beams is presented. Beams were constructed coupling glass and steel, glass and pultruded profile or alternating glass sheets with glass fibres and were subjected to bending tests. Preliminary studies regarding the formation of cracks were performed using the Digital Image Correlation technique
Flax and Basalt Fibers as Reinforcement for Wooden Beams
No full textThe results of an experimental campaign on wooden structural elements reinforced with FRP in natural fibers of basalt and flax are presented. At first a study regarding the composite materials was made. Tension tests and pool-out tests were performed on specimens made up of different types of fibers. In the second phase different types of timber beams of various sizes were prepared applying natural fiber reinforcements and were then subjected to bending tests on four points. The results were compared with the ones obtained by tests on unreinforced beams or reinforced with glass or carbon fiber and they were satisfactory in terms of increment of strength
Experimental analysis of laminated glass with different interlayers
No full textAn experimental study of the flexural behavior of laminated glass panes made with different interlayers was carried out. The glass elements were created with two glass sheets having a length of 1100 mm, a width of 360 mm and a thickness of 4 mm. These were laminated with either a PVB interlayer or a SGP interlayer. The glass elements were tested with a four point bending test using the same load rate with an electronic hydraulic testing machine, in displacement control conditions. A finite element model, able to reproduce the elastic phase and the post critical phase, was performed. It was also possible to model the behavior of the laminated glass sheet in the post critical phase, considering the cracked section. The behavior of the interlayer in the different conditions of time loading was modeled. In this case this model reproduces the cracked glass behavior well
The technique of digital image correlation to identify defects in glass structures
No full textThe article describes an experiment using the technique of digital image correlation (DIC) to identify and analyse defects in glass structures. The investigation involved three sets of glass structures i.e. float glass sheets, with or without any defects, and subjected them to bearing tests. The digital image correlation technique perfectly identified not only the position and size of the defect, but also the magnitude of deformations around the defect itself. Low stress values also indicate that strains concentrate around the defects. This enables the DIC method to be used to investigate the quality of glass elements, to detect the presence of defects and to monitor the most critical structural elements. The results obtained with the DIC technique were confirmed by comparing them with data gathered from the analysis of the fracture surface
Hybrid steel-fibre reinforced glass beams - Experimental and numerical analysis
No full textA study concerning steel-fibers reinforced glass beams is presented in this paper. The beams were obtained by gluing glass sheets with epoxy resin and applying the steel fibers reinforcement at the intrados. UHTSS fibers and stainless steel fibers were used. Tests on resins permitted to evaluate the adhesion between glass sheets and between glass and steel fibers. The beams were tested in four point bending. The effect of the reinforcement was evaluated, comparing the limit elastic phase and the post-critical phase. The reinforcement gives to the beams a good degree of safety in case of failure and avoids the collapse of the element as its presence provides a good post-cracking behavior
Flexural performance of hybrid beams made of glass and pultruded GFRP
No full textThis study is aimed at the investigation of hybrid beams specially constructed by coupling glass and pultruded fibreglass profiles. The investigation consists of a study of the flexural behaviour of the hybrid system using four-point bending tests, preceded by adhesion tests to check the validity of the bond between the two components. The goal is to find the technological solution for a beam that reaches a first cracking load value high enough to ensure its use in a wide range of applications. This solution should also show a post-critical ductile behaviour suitable enough to prevent the typical fragile fracture of glass structural elements. The most important effect of the pultruded profile is the contribution given in the post-critical phase, since it allows the cracked beam to transfer the stresses. Analytical modelling based on the load-deformation characteristics using simple calculations was performed in order to interpret the experimental results in a fast and simple way and to obtain more in-depth knowledge on the behaviour of the structural elements tested
Experimental analysis of adhesion phenomena in fibre-reinforced glass structures
No full textAdhesion phenomena in hybrid glass structures made of glass and composite material are of critical importance in order to achieve high performance. As a contribution to the study of this topic, an experimental and analytical investigation was performed. It looked into the adhesion phenomena of two different composites, such as GFRP (Glass Fibre Reinforced Polymers) and SRP (Steel Reinforced Polymers), using different types of resins and various interface geometries. The experiment was carried out on samples subjected to shear traction tests, in order to examine the load transfer mechanism and the failure mode of the adhesive joint, to evaluate the optimal bond length and to perform a validation using substantiated theories. A formulation studied on the basis of the experimental results is also proposed herein to evaluate debonding resistance and the optimal bond length
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