Antonio Viscusi

Metallization of Vitrimers by cold spray: A preliminary study VISCUSI Antonio, PERNA Alessia Serena, MARTONE Alfonso, PALMIERI Barbara, CILENTO Fabrizia, AM

In this work, the effects of some geometric and mechanical parameters that characterize curved and relatively soft structures integrated with piezoelectric actuators are investigated. The effect of parameters such as the curvature, location, and extension of the piezo device, as well as the thickness of the bonding and its strength, are considered in view of a potentially lighter model that replaces the piezoelectric device via its actions, namely pin forces, whose layout and values are strongly dependent on the curvature. When comparing the results obtained by a finite element model of the structure with the piezo device and of the structure alone under the action of pin forces, dedicated indicators were found, which could be useful to support lighter modeling approaches and to predict the authority of the piezoelectric device.

Metal foams are a relatively new class of materials with many interesting combinations of physical and mechanical properties. Among them, the closed-cells aluminum foams are the most interesting for structural applications in the aerospace industry. There exist different methods to produce metal foams. An innovative manufacturing technique was developed in this study, proving the possibility to produce closed-cells aluminum foams through the cold spray additive manufacturing technology (CS). In particular, two different sets of samples were produced by varying the cold spray process parameters aiming at: i) studying the advantages and the issues of cold spray for manufacturing precursors for metal foams; ii) analyzing the correlation among the CS printing strategy and parameters, the foaming process and the physical and the morphological characteristics of the resulting foams; iii) finally, finding appropriate conditions to form closed-cells aluminum foams via CS.

Fibre-reinforced plastic (FRP) materials are attracting growing interest because of their high specific mechanical properties. These characteristics, in addition to a high level of tailorability and design of freedom, make them attractive for marine, aerospace, automotive, sports and energy applications. However, the large use of this class of material dramatically increases the amount of waste that derives from end-of-life products and offcuts generated during the manufacturing processes. In this context, especially when thermosetting matrices are considered, the need to deeply study the recycling process of FRPs is an open topic both in academic and industrial research. This review aims to present the current state of the art of the most affirmed recycling technologies used for polymeric composites commonly used in industrial applications, such as carbon and glass FRPs. Each recycling method (i.e., chemical, thermal and mechanical) was analysed in terms of technological solutions and process parameters required for matrix dissolution and fibre recovery, showing their advantages, drawbacks, applications and properties of the recycled composites. Therefore, the aim of this review is to offer an extensive overview of the recycling process of polymeric composite materials, which is useful to academic and industrial researchers that work on this topic.

In the present work, the response of composite hybrid laminates made of carbon and glass fibers in different stacking configurations was tested under low-velocity impact loads. Experimental drop impact tests were conducted on three different stacking sequences and three rising impact energy levels. The results from the tests were assumed for the development and validation of a numerical impact model reproducing for each stacking sequence and all the impact energy levels, the laminates impact response. The validated model investigated the occurred damage mechanisms, their distribution in the panel thickness and their extension on the plane of the laminate. Depending on the stacking sequence and the impact energy level, the energy absorption capacity was related to the dominant damage mechanism. The percentage contribution of interlaminar and intralaminar damages was presented and conclusions were drawn about the influence of stacking sequences on energy absorption and damage characteristics.

The cold spray (CS) process is the latest solid-state deposition method that has gained significant awareness for the metallization of polymer matrix composites (PMCs) materials to modify their surface properties, including electrical or thermal conductivity and electromagnetic shielding. In comparison with other coating processes, CS allows for the production of metallic coatings without the necessity to reach the melting temperature of the sprayed particles and provides a way to deposit resistant materials with improved properties onto various components to minimize wear, erosion and corrosion. For the first time in the literature, this work has the innovative goal of applying the life cycle assessment methodology to the case study of the CS production process in order to ascertain whether CS could be framed in the realm of green technologies offering interesting opportunities to improve manufacturing sustainability. In particular, the environmental impact of CS associated with the metallization process of PMCs was considered in terms of energy consumption and CO₂, NO_x and SO₂ emissions, which are used as indicators in the life cycle assessment. When compared to different coating processes, the results suggest that CS has a large potential to reduce the environmental effects connected with the products in terms of the amount of CO₂ and hazardous emissions created throughout the process.

Cold Spray is an innovative technology to create coatings through the impact of metallic particles on substrates. Its application to composites’ surfaces is recently attracting the attention of the scientific community thanks to the possibility to functionalize and improve their thermal and wear properties. Within this context, the generation of the first metal-to-composite layer is fundamental. This work presented an experimental investigation of a composite panel, reinforced with glass fibers and coated with aluminum particles. The coating investigation was carried out through active pulsed thermography, analyzing the thermal response of single and double hatches. The thermal outputs were compared with a standard microscopic analysis, with a critical discussion supporting the identification of factors that influence the thermal response to the pulse: (1) layer’s thickness; (2) cold spray coverage; (3) layer compactness; (4) particle-substrate adhesion; (5) particle’s oxidation; and (6) surface roughness.