Search results for " FLEX"
showing 10 items of 320 documents
Longitudinal Flexure as a Method for Determining the Flexural Strength of Composite Materials
2004
A method is presented for determining the flexural strength of composites from tests on pinned specimens in axial compression. This scheme is close to the so-called Euler buckling model, but the load is applied eccentrically, and the bar is bent practically from the beginning of loading. An analytical model is proposed for calculating the flexural stress in longitudinal flexure of a thin bar in the case of large displacements. The problem is solved in elliptic integrals of the first and second kinds. The analytical model shows an excellent agreement with experiments. The results obtained are compared with experimental tension data. A device is also designed for testing composite bars in lon…
Mechanical Behaviour of a Green Sandwich Made of Flax Reinforced Polymer Facings and Cork Core
2015
Abstract This work investigates the flexural behavior of a composite sandwich made of flax fibers reinforced skin facings and an agglomerated cork core, to be employed as an eco-friendly solution for the making of structural components of small sailing boats. An experimental mechanical characterization of the strength and stiffness flexural behavior of the proposed sandwich is carried out, providing a comparison of performances from three implemented assembling techniques: hand-lay-up, vacuum bagging and resin infusion. Sandwich beams have been tested under three point bending (TPB) at various span lengths. A procedure is also proposed and implemented to consider the potential influence of …
Salt-fog spray aging of jute-basalt reinforced hybrid structures. Flexural and low velocity impact response
2017
Abstract In this work, a study on the aging resistance of jute and jute-basalt interply hybrid laminates exposed to salt-fog is presented with the aim to investigate the possibility to enhance the durability of natural fiber reinforced composites for marine application by a ply-substitution approach. In particular, jute and basalt/jute reinforced composite plates were manufactured by vacuum assisted resin infusion in two different staking sequences (i.e., intercalated and sandwich-like basalt-jute) and aged under salt fog conditions. The effects of the accelerated aging at increasing times on the mechanical response of laminates were assessed in both quasi static (three point bending) and d…
Mechanical properties of pultruded glass fiber-reinforced plastic after moistening
2012
Abstract The kinetics of moisture sorption under immersion in water at room and elevated temperatures and flexural characteristics of dry (conditionally initial) and wet (moistened up to saturation level) composite material were investigated on flat specimens of polyester based glass fiber-reinforced plastic, cut from I-beam pultruded profile. It was found that the coefficients of diffusion and swelling are different in three principal axis of the composite. The former have the largest value in fiber axis direction, but the latter – in transverse to fiber axis direction out of plane of the layers. The observed difference in kinetics of mass gain and change of volume strain for the specimens…
Molecular dynamics of CH4/N2 mixtures on a flexible graphene layer: adsorption and selectivity case study
2019
We theoretically investigate graphene layers, proposing them as membranes of subnanometer size suitable for CH4/N2 separation and gas uptake. The observed potential energy surfaces, representing the intermolecular interactions within the CH4/N2 gaseous mixtures and between these and the graphene layers, have been formulated by adopting the so-called Improved Lennard-Jones (ILJ) potential, which is far more accurate than the traditional Lennard-Jones potential. Previously derived ILJ force fields are used to perform extensive molecular dynamics simulations on graphene's ability to separate and adsorb the CH4/N2 mixture. Furthermore, the intramolecular interactions within graphene were explic…
Theoretical and Experimental Research on Mechanical Behavior of Layered Composites Laminates
2014
The aim of the research of the experiment was to determine the mechanical characteristics of the composite layered material. There has been two types of experimental tests i.e. test for determining the tensile modulus of elasticity of the material, the maximum voltage and the elongation at break of the material. The second type of test is the flexural test was intended to determine the maximum load that the breaking is produced by bending.
Analytical Prediction of the Flexural Response of External RC Joints with Smooth Rebars
2018
Nel presente lavoro viene presentato un modello analitico in forma chiusa in grado di riprodurre la risposta flessionale monotonica di nodi esterni trave-colonna in c.a. con armature lisce. La colonna viene sottoposta a carico verti-cale costante e la trave ad una forza laterale crescente monotonicamente applicata all’estremità. Il modello si basa sul comportamen-to flessionale di trave e colonna adottando un modello di cerniera plasticità concentrata che include lo scorrimento delle armature della trave. Si assume un dominio sforzo normale-momento bilineare semplificato da cui viene derivato il momento ultimo associato alla forza assiale di progetto. Per il nodo viene adottato un modello c…
Fatigue crack growth of new FML composites for light ship buildings under predominant mode II loading condition
2019
The use of light but strong materials is largely studied in various area of the shipbuilding, this because the need of reducing the weight, and especially the weight of all the structures above the main deck assume primary importance for the stability. Traditionally in fast boats like fast ferries, hydrofoils, patrol boats, the typical materials are Aluminum alloy or composites, both those materials have advantages and disadvantages, but the new development of technologies made possible to combine them, in order to have a new material, combining the advantages of both, in terms of fatigue resistance, firefighting characteristics. In this paper, predominant mode II fatigue delamination tests…
Fibrous reinforced concrete beams in flexure: Experimental investigation, analytical modelling and design considerations
2008
Abstract The flexural behavior of plain and fibrous reinforced concrete (FRC) beams under monotonic and cyclic actions was analysed. Twelve beams were reinforced with top and bottom longitudinal deformed steel bars and transverse steel stirrups. Concrete, having 30 MPa cylindrical strength, was reinforced with hooked steel fibres at a volume percentage of 1%. Beams, 600 mm in length and with a square side cross-section of 150 mm, were tested in flexure using a three point bending test, adopting three different cover thicknesses of 5, 15 and 25 mm, respectively. The results obtained show that the addition of fibers increases the bearing capacity of the beams and ensures more ductile behaviou…
Three-Point Flexural Behaviour of GFRP Sandwich Composites: A Failure Map
2010
In this work, the failure mechanisms of GFRP/PVC foam core sandwich structures subjected to three-point bending are analysed. By varying the skin thickness (t ) and the span length between supports (l), experimental tests were carried out in order to find the relationship between the geometrical configuration of the sandwiches and the failure mechanism. By plotting failure mechanism on a graph of l against t , a failure map was created identifying the three typical failure mode regions of these sandwiches. The graph clearly shows the failure mode corresponding to each combination of l and t . To help optimise the use of these sandwich beams as structural elements, a theoretical failure mode…