Search results for "Composite Materials"

Strain Measurement on Composites: Effects due to Strain Gauge Misalignment

2011

The present work analyses the errors affecting the strains measured by misaligned strain gauges installed on orthotropic-composite laminae. Various analytical relationships are derived showing that, besides the fibre and strain gauge orientations, the misalignment error in unidirectional off-axis orthotropic composite samples depends also on the lamina stiffness properties (E(1), E(2), nu(12), G(12)). If the fibres are aligned with the loading axis, it is found that the higher Poisson's ratio nu(12) is the only elastic property influencing the misalignment error. Experimental results are shown confirming the theoretical predictions.

Atmospheric pressure non-equilibriumplasma for the production of composite materials

2014

In the evolving field of tissue engineering, continuous advances are required to improve scaffold design and fabrication to obtain biomimetic supports for cell adhesion, proliferation, penetration and differentiation. Both electrospun fibrous scaffolds and hydrogels are used in this field since they well reproduce the structure of the extracellular matrix (ECM) of many biological tissues. Limitations of these two types of materials can be overcome through their combination, by developing composite structures combining enhanced mechanical properties (provided by the fibrous components) and improved cell penetration (provided by the gel phase) in a superior ability to mimic natural ECM that i…

Photoreforming of organics in aqueous suspension of Nb2O5/C3N4 composites to obtain H2

2023

Photocatalysis based on the use of semiconductors has gained, during the recent years, increased attention as promising sustainable process for H2 and fine chemicals production, given the possibility of activating such photocatalysts by visible light radiation. The photo-reforming activity in this work has been measured under both UV-LED irradiation and natural sunlight illumination. Moreover, the presence of metallic Pt as co-catalysts has been studied. Carbon nitride (C3N4) based materials are good candidates for solar energy conversions. The choice of C3N4 and Nb2O5 arises from the fact that their heterojunction can lead to lower recombination between the photo-generated electrons and ho…

Effect of Multi-Impact on Qiqh Carbon/Epoxy Composite LaminateEffect of Multi-Impact on Qiqh Carbon/Epoxy Composite Laminate

2018

This work is motivated by increasingly used of composite structures under severe loading conditions. During their use, these materials are often subjected to impact as for example, in the aeronautical field the fall of hailstone on structure composites. In fact, the low energy traditional impact tests don’t allow to see the evolution of the damage and don’t permit also to compare the best tolerance to impact between different stratifications. The multi-impact tests made it possible to find a solution to this problem. In this work, multi-impact tests are performed on three carbon/epoxy stratifications. The final goal is to predict the durability of the composite structures during impact load…

Progressi sperimentali e numerici nella valutazione dell'integrita strutturale dei solidi mediante Thermoelastic Stress Analysis

2023

NANOARCHITECTURE: A NEW CREATIVITY IN CONSTRUCTION

2015

Object of this work is the construction industry that, until the industrial revolution, has always been a major human activity and nowadays still represents a massive sector of production. Nevertheless, it often deals with coarse components and systems as, in the last century, investments in research remained lower than in other industrial sectors as army, medicine, etc.. Only recently, with the development of technology and the advances in materials science and engineering, a new generation of products, that are both of higher performance and more economically viable, is to be realizing as a competitive route to achieve a real sustainable growth and innovation. Nowadays, the market show hu…

Photocatalytic Generation of H2 by Photoreforming of Organics in Aqueous Suspension of Nb2o5/C3n4 Composites

2023

Bare and composite materials based on C3N4 and Nb2O5 have been used as photocatalysts for the photoreforming of aqueous solutions of oxygenated compounds. Both Nb2O5 and Nb2O5/C3N4 composites have been prepared by hydrothermal synthesis and all of them were physical-chemically characterized. In this work two different carbon nitride species i.e. graphitic (g-C3N4) or thermo-etched (TE-C3N4) were used both alone or coupled with Nb2O5. The photo-reforming activity has been measured under UV irradiation by using the semiconductors in the presence of Pt as co-catalysts and, in the case of the best material, it was, for the first time, measured and compared also under natural solar irradiation. …

New composite materials made up of nanofibers and hydrogel as biomimetic scaffolds for human pluripotent stem cell culture

2014

Characterization of three-dimensional microstructure of composite materials by X-ray tomography

2016

Analysis methods for X-ray microtomographic images of short fibre composite materials were developed. The methods enable estimation of microstructural properties of the material, e.g., aspect ratio and orientation of fibres. Being based on X-ray microtomography and image analysis, the methods are nondestructive and do not require user intervention. In particular, a method for determination of the aspect ratio of fibres was first developed. The method contains an assumption about similarity of the shape of the fibres. The assumption was relaxed in an improved method that can estimate cross-sectional properties of fibres, too, e.g., cross-sectional area. Additionally, the effect of finite ima…