Search results for " fibre"

EFFETTI DI NANOTUBI SULLA RESISTENZA A FATICA DI BIOCOMPOSITI A FIBRE CORTE RANDOM

2019

In order to comply with the recent regulations in terms of environmental protection, biocomposites reinforced with natural fibers are increasingly used in the automotive sector, for the replacement of synthetic materials in semi-structural applications as panels, filling material, coating, dashboards, etc. The good mechanical performances of these materials, mixed with low weight and low cost, also make it possible to minimize the weight of the vehicle, and therefore consumption, but also the relative production costs. These are composites with random short fiber appreciated for their good stiffness, generally well above that of the matrix alone. Due to the peculiar "transverse" damage phen…

ANALISI DEL COMPORTAMENTO MECCANICO DI SANDWICH ECO-COMPATIBILI RINFORZATI CON FIBRE NATURALI

2015

The increasing environmental sensitivity in many industrial fields, from automotive to aeronautics to naval field, has led to an increasing demand of new bio-materials or renewable structural materials. In order to give a contribution to the design of eco-compatible structural materials, in this work new sandwich materials constituted by a core made by balsa and skins made by a composite material made by a “green” epoxy reinforced by agave fibers extracted from striated and americana agave obtained in Sicily by a proper research program financed by European founds. Previous theoretical analysis followed by systematical experimental analysis of the core, of the skins and the of the sandwich,…

Implementation of a fast and low cost IR-NDT technique by means of a Square Pulse modulated Lock-In Thermography

2012

This work describes the development of an IR-NDT procedure based on a lock-in signal treatment in the frequency domain to obtain phase-contrast defect signatures. Heat stimulation is obtained by periodically shattering a common low-power halogen lamp. The delivered heat is then modulated as a train of square waves with multi-frequency harmonic content. The proposed lock-in algorithm is able to selectively retrieve phase and amplitude information at various frequencies of the acquired temperature, acting also as a narrow band filter to improve defect-signature to noise ratio. The procedure is implemented and evaluated by means of low cost IR equipment to investigate artificially defected thi…

Fatigue behavior of self-piercing riveting of aluminium blanks and carbon fiber composite panels

2012

Environmentally Friendly Composites and Surface Treatments for Metal-to-Composite Hybrid Joints for Marine Application

2022

In this study, the use of natural fibres (flax and basalt) in combination with a recyclable epoxy matrix based on cleavable amines is suggested for improving the sustainability of marine industry. In addition, a new and eco-friendly anodizing process based on tartaric sulfuric acid solution (TSA) and a pore widening step in a NaOH aqueous solution was carried out on aluminium alloy (AA5083) to evaluate its effect on the adhesion strength and damage tolerance after low velocity impact of co-cured adhesive joints with a basalt fibre reinforced and recyclable laminate. The durability in marine environment was simulated by exposing samples to salt-fog spray conditions over a period of 90 days. …

Durability of flax-basalt hybrid composites for marine applications

2015

The aim of the present work is to evaluate the influence of external layers of mat basalt on the durability behaviour and performances of flax/epoxy laminates. To this scope, long-term aging tests were performed to evaluate the durability of the two different laminates in critical environmental conditions. In particular, Flax composites were constituted by ten layers of bidirectional flax fabric whereas hybrid laminates (i.e. Flax-Basalt) were produced by replacing four external layers of bidirectional flax with four layers of basalt mat. Both laminates had a total average thickness equal to 3 mm. The samples were exposed to critical environmental conditions following the ASTM B 117 standar…

Modelling the structure-property relationships of high performance PBAT-based biocomposites with natural fibers obtained from Chamaerops humilis dwar…

2022

Two fibrous fillers were achieved from stalks and leaves of Chamaerops humilis dwarf palm and tested as reinforcing agents for poly(butylene adipate co-terephthalate) (PBAT)-based composites. The influence of filler type and content on the morphomechanical properties of the green composites was assessed. The outcomes of tensile tests pointed out that both fillers are strong candidates to overcome the two main limiting aspects of PBAT, that is, the lack of both stiffness and cost-effectiveness, while preserving its stretchability and environmental sustainability. The remarkable stiffness increments (up to 300%), combined with fair retention of stretchability (33%) and doubled resistance, led…

The durability of basalt fibres reinforced polymer (BFRP)

2014

The technology of dry assembly for the production of multi-layer panels has evolved over the past 30 years, becoming an efficient alternative to traditional systems. The direction taken by the market has been increasingly drawn to eco-sustainable systems and in this way, the interest in the use of laminated composite panels for cladding, basalt fibres based. Basalt is a natural rock, silica based, which is produced through a variety of industrial processes into filaments, wool, chopped strands and fabrics. It is characterized by high resistance in chemically aggressive environments, high fire resistance, high mechanical resistance to compression and bending. The study focuses on two types o…

Effect of sheep wool fibres on thermal-insulation and mechanical properties of cement matrix

2015

The use of sheep wool as reinforcement of cement in order to produce mortar or plaster involves several advantages for environment and energy. Moreover, in several regions it is treated as a waste and, consequently, its employ is characterized by low cost. Aim of this paper is to evaluate the influence of wool fibres on thermal conductivity and mechanical properties of cement. The samples were prepared using wool fibres, obtained from a breed of Sicilian sheep, with three different length (i.e. 1 mm, 6 mm and 20 mm). Moreover, in order to evaluate the influence of fibre content, the samples were prepared by varying the fibres weight fraction up to maximum level. The thermal conductivity of …

Failure mechanisms of flax/epoxy laminates with open hole: a failure map

2017

Aim of this paper is the investigation of the pin/hole contact stress and failure mechanisms of flax/epoxy composite laminates underwent to tensile bearing tests. In particular, the maximum loads and failure modes are evaluated at varying joint geometry. In order to optimize the use of composite materials in structural applications, an experimental failure map, identifying main failure modes of mechanically fastened joints, is obtained by evaluating failure modes (i.e., net tension, shear out, cleavage and bearing) as a function of the pin diameter and the position of the hole from the free edge of the laminate. Main goal of this paper is give a simple experimental methodology to support th…