Search results for "Sandwich"

A Multilayered Plate Theory with Transverse Shear and Normal Warping Functions

2016

A multilayered plate theory which takes into account transverse shear and normal stretching is presented. The theory is based on a seven-unknowns kinematic field with five warping functions. Four warping functions are related to the transverse shear behaviour, the fifth is related to the normal stretching. The warping functions are issued from exact three-dimensional solutions. They are related to the variations of transverse shear and normal stresses computed at specific points for a simply supported bending problem. Reddy, Cho-Parmerter and (a modified version of) Beakou-Touratier theories have been retained for comparisons. Extended versions of these theories, able to manage the normal s…

The effects of water absorption and salt fog exposure on agglomerated cork compressive response

2022

The replacement of synthetic foams with agglomerated cork in sandwich composites can meet the increasing environmental concerns. Its peculiar morphology and chemical composition lead to outstanding dimensional recovery that endorsed a broad investigation of its compressive behavior. The knowledge of neat material response is fundamental to obtain a reliable design dataset, but it is necessary to consider all the environmental factors (water, moisture and sunlight) that significantly modify material mechanical properties. In view of this, the present work investigates the effect of distilled and seawater absorption and salt fog exposure on the compressive behavior of two agglomerated corks w…

Evaluation of aging behavior under salt-fog spray conditions of green sandwich structures

2018

In this paper, the aging resistance of sandwich structures made with cork agglomerate as core and flax-reinforced polymeric laminates as face sheets was investigated for the first time. In order to evaluate their durability in a hostile environment, a sandwich plate was manufactured by vacuum bagging technique and aged under salt-fog spray conditions, according to ASTM B 117 standard. The evolution of the sandwich mechanical properties during the aging exposition was analyzed by carrying out quasi-static flexural tests and Charpy impact tests both on unaged specimens and on specimens aged for 10, 25, and 60 days, respectively. The quasi-static experimental results showed that despite the sa…

On the Finite Element Simulation of Secondary Operations on Metallic Foams

2007

Metallic foams have been recently introduced also as industrial materials due to their well known advantages. In fact, their low mass in conjunction with the good thermal and mechanical properties push toward an extensive diffusion in manufacturing industry. In the study here addressed, a very accurate investigation concerning the latter two aspects has been carried out. In fact, a secondary manufacturing process, i.e. the foam bending, has been taken into account. Anyway, all the knowledge derived for sheet metal bending is not directly applicable to the foams. A finite element code has been utilized for modeling the foam behavior during the bending processes and an accurate material rheol…

Glass/basalt hybrid sandwiches for nautical applications

2011

A numerical solution that determines the temperature field inside phase change materials: application in buildings

2013

The use of novel building materials that contain active thermal components would be a major advancement in achieving significant heating and cooling energy savings. In the last 40 years, Phase Change Materials or PCMs have been tested as thermal mass components in buildings, and most studies have found that PCMs enhance the building energy performance. The use of PCMs as an energy storage device is due to their relatively high fusion latent heat; during the melting and/or solidification phase, a PCM is capable of storing or releasing a large amount of energy. PCMs in a wall layer store solar energy during the warmer hours of the day and release it during the night, thereby decreasing and sh…

INVESTIGATION OF THE INDENTATION BEHAVIOUR OF FOAM CORED LIGHTWEIGHT COMPOSITE SANDWICHES

2011

ANALISI DEL COMPORTAMENTO MECCANICO DI SANDWICHES GREEN COSTITUITI DA PELLI IN BIOCOMPOSITO E CORE IN BALSA/SUGHERO

2022

Negli ultimi anni l’aumento della sensibilità nei confronti della salvaguardia ambientale, anche attraverso apposite norme in materia di lotta all’inquinamento e di riciclo dei materiali a fine vita, ha portato ad un notevole interesse dei ricercatori verso i cosiddetti compositi green, materiali costituiti in genere da rinforzi di origine naturale e matrici “bio-based” a basso impatto ambientale. Una categoria interessante di materiali innovativi, caratterizzati da una elevata resistenza a flessione unita ad un basso peso specifico, è rappresentata dai cosiddetti sandwiches, costituiti in genere da robuste pelli in composito fibro-rinforzato e da un core in materiale molto leggero e poco r…

Iron(II) complexes of naphthalenes. X-ray structure of [cyclopentadienyl-iron(II)-η6-octamethylnaphthalene]PF6

1992

Abstract Complex ions [cyclopentadienyl-Fe(methylnaphthalene)]+ with 4 to 8 methyl substituents have been prepared from [CpFe(o-dichlorobenzene)]+ by a photochemical ligand exchange. Complexation shifts have been determined for 1H and 13C resonances of the η6-bonded naphthalenes. The X-ray structure of [CpFe(octamethylnaphthalene)]PF6 0.5 acetone has been determined. Crystals are monoclinic, the space group C2/c with unit-cell dimensions a = 10.689(4), b = 22.391(5), c = 20.550(4)A, β = 93.41(2)°, Z = 8. The structure determination established a distorted molecular geometry of the octamethylnaphthalene that is different from the free arene and its Cr(CO)3 complex.

Experimental and theoretical characterization of the strong effects on DNA stability caused by half-sandwich Ru(II) and Ir(III) bearing thiabendazole…

2020

Abstract: The synthesis and characterization of two half-sandwich complexes of Ru(II) and Ir(III) with thiabendazole as ancillary ligand and their DNA binding ability were investigated using experimental and computational methods. 1H NMR and acid–base studies have shown that aquo-complexes are the reactive species. Kinetic studies show that both complexes bind covalently to DNA through the metal site and non covalently through the ancillary ligand. Thermal stability studies, viscosity, circular dichroism measurements and quantum chemical calculations have shown that the covalent binding causes breaking of the H-bonding between base pairs, bringing about DNA denaturation and compaction. Addi…