Low temperature impact of composite hull wall with floating rigid body

An experimental activity conducted in order to assess the impact behavior, at room and low temperature, of laminates used in the shipbuilding industry, was reported. The conditions which reproduce the impact of a hull at low temperature with a solid body suspended in the water was reproduced. A test equipment was designed and realized to reproduce the real material behaviour in water to obtain a load distribution on the entire surface of the specimen. The results were obtained impacting the laminates placed between the cilyndrical steel impactor and the bag containing water. A falling weight machine equipped with an instrumented steel impactor and a thermal chamber was adopted for the experimental tests. Laminates made by vinyl ester matrix and carbon fibres were considered during the tests, and the results in terms of impact behaviour in hostile environments were compared to what obtained at room temperature. The data obtained under a distributed load were also compared with the results of impacts at concentrated loads

Delamination on GFRP laminates impacted at room and lower temperatures: Comparison between epoxy and vinylester resins

Low velocity impact tests at three different impact energy values and three different temperatures, were performed on glass fibre composite laminates made by infusion technology. Two different resins, epoxy and vinylester, were considered to impregnate the fibres: the first is mainly of aeronautical interest whereas the second one is mainly applied in Naval field. The specimens were first completely destroyed to obtain the complete load-displacement curve. The latter allowed the evaluation of the increasing impact energies, 5, 10 and 20J, used to investigate about the start and propagation of the damage inside the laminates. The delamination was investigated by the very commonly used Ultra Sound technique and the results obtained on the different materials at different temperatures were compared. A general better behaviour of vinylester resin was noted. © 2016 Author(s)

Ultrasonic inspection of composites materials: Application to detect impact damage

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Experimental Investigations on Bending Collapse Modes of Innovative Sandwich Panels with Metallic Foam Core

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fe analysis of low density hemp epoxy composites produced by a new continuous process

Abstract This paper aims to present a new grid composite structure obtained by stacking hemp fabric layers impregnated by resin using a new continuous process. Both the process feasibility and the mechanical properties of the obtained specimens were investigated in terms of tensile and flexural response. In addition, the effect of the superimposition error of the layers, that can affect the density and the mechanical properties of the produced bio-composites, was studied both experimentally and numerically by finite element models (FEM). The results showed that the process is able to produce low density composites possessing interesting specific mechanical properties with a good level of repeatability

Zeolitized tuffs in pedotechnique for quarry restoration: evaluation of phytonutritional efficiency in ^AUP model horizons

A study was started aiming at assessing the suitability of zeolitized tuff as optimal mineral Human Transported Materials (HTMs) in pedotechnologies for quarry restoration

Andic soils and catastrophic mudflows in Italy: morphological and hydropedological evidences

In Italy rapid landslides are the most frequently occurring natural disasters and, after earthquakes, cause the highest number of victims. In this contribution we attempt to prove that there exist a tight connection between the presence of a specific soil type, namely andic soils, and the occurrence of the main catastrophic mudflows and debris flows occurred in Italy in the last decades. The study was performed by means of an integrated pedological and hydrological analysis on the detachment crowns of some of the most important catastrophic mudflows and debris flows occurred in Italy in the last decades and involving/evolving surface soils. The results at both regional (Campania) and National (Italy) scale clearly show that despite the large variability of the environmental settings of the studied sites there are indeed some striking homogeneous soil features in the detachment crowns including (i) soil morphology, (ii) andic features ranging from high to moderate, (iii) high water retention throughout a large range of pressure heads. Results seem to reveal clear cause-effect evidences between andic soils and the investigated catastrophic mudflows/debrisflows; this must be related to the unique physical properties of these soils inducing high landslide vulnerability

CFRPs drilling: comparison among holes produced by different drilling strategies

Abstract The drilling process of CFRPs is the most commonly employed machining operation owing to the need for joining these structures. However, these materials are prone to delaminate during the process and the presence of these defects can be a cause of rejection of these components. Therefore, this paper aims on the study of alternative drilling strategies such as: the orbital and a new drilling strategy (called circular drilling) to reduce the delaminations extension. Holes 8 mm in diameter were obtained by using different drilling strategies and cutting conditions and their influence on the cutting forces and delamination factor was studied

Recyclability Process of Standard and Foamed Gypsum

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