ABSTRACT The present study aims at investigating the effect of process parameters on environmental sustainability of 3D printing of short fiber-reinforced polymer composites. A preliminary study allowed defining the printing parameters, in terms of printing speed, extrusion temperature and layer thickness, which guarantee low energy consumption. Then, the environmental behavior of two 3D printable composite materials, glass fiber-reinforced (GlassPA) and carbon fiber-reinforced (CarbonPA) polyamide, was investigated using the Life Cycle Assessment methodology, to provide a comprehensive overview of the considered materials and to support the sustainable development of industrial additive manufacturing processes. The functional unit was chosen taking into account the mechanical properties of the two short fiber-reinforced composites. To this purpose, tensile and flexural tests were performed on specimens produced by Fused Filament Fabrication process to evaluate the mechanical properties of printed materials. Scanning electron microscopy was used to observe the different filament morphology affecting the materials performances. Experimental tests showed that CarbonPA exhibits mechanical performances higher than those of GlassPA. Due to the weight reduction that can be accomplished by means of carbon fibers, CarbonPA results the most environmentally friendly alternative in tensile loads applications. On the contrary, for flexural loads applications, GlassPA exhibits lower environmental footprint.

Process parameters effect on environmental sustainability of composites FFF technology

Abstract In this study, the pin bearing behaviour of a 3D printed composite material with Kevlar reinforcement was analysed. Three different experimental tests were designed to determine the effects of fibre orientation, layer design, and fibre distribution along the specimen thickness. Furthermore, the pin-bearing strength and stiffness were analysed using statistical methods as analysis of variance. The results indicate a significant increase in bearing strength and stiffness for at least two fibre orientations, i.e. 0°and 90° with respect to the pin displacement. The results also highlight a no significant variation of strength and stiffness for parts produced adopting a mixed or single fibre orientation; finally, the findings do not indicate any significant influence of the fibre layer position inside the specimen, i.e. this parameter does not limit the freedom when designing a fibre-reinforced part. 

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Pin-bearing mechanical behaviour of continuous reinforced Kevlar fibre composite fabricated via fused filament fabrication

This paper describes a configuration of drone swarm that can be used in support of the actions to limit the virus spread during a pandemic period, such as the COVID-19 emergency. The proposed study analyzes a system architecture for the identification of individuals affected by the virus, estimating their biomedical parameters. The presented method exploits different techniques, such as stereoscopy vision, thermal measures and remote photoplethysmography, to acquire standalone data that can be compared to evaluate the target risk. The tested solutions are proposed to measure the social distancing among multiple individuals, the skin temperature of a target person, and the image photoplethysmography signal, that are critical parameters to detect a potentially infect individual during the COVID-19 pandemic. Different test strategies were adopted to carry out the mentioned tasks. To measure the distance between target individuals, two drones equipped with visible band cameras were employed. To measure the skin temperature of a target, a drone equipped with a thermal camera was adopted, performing measures at different distances and heights. To obtain the image photoplethysmography signal, a video file from drone camera is processed. Image processing techniques are required to elaborate the data coming from several images and videos acquired by drones. Comparing the measures, altered biomedical parameters of several targets can be detected and later tested with medical equipment.

Performance Analysis for Human Crowd Monitoring to Control COVID-19 disease by Drone Surveillance

The recent performance improvements of the Micro-Electro Mechanical Sensor, in terms of noise parameters, have allowed increasing their application fields such as consumer, structural health monitoring, and navigation applications thanks to their advantages in terms of cost, small dimension, low power consumption, and versatility. Furthermore, in aerospace and automotive sectors, the sensors adopted must strictly respect the noise parameters that classified the inertial sensors, i.e., bias instability and random walk, typically reached by tactical-grade sensors with higher cost. To make low-cost consumer-grade MEMS sensors suitable also for navigation applications, a redundant-IMU solution has been the subject of research. The authors proposed a suitable strategy to fuse the measurements obtained from all the IMU composed of an accelerometer and gyroscope mounted on a suitable and innovative 3D structure, based on the evaluation of the Allan variance and the use of weighted average.

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Innovative Fusion Strategy for MEMS Redundant-IMU Exploiting Custom 3D Components

The paper presents an innovative strategy to measure the initial heading of a vehicle in the local reference frame by means of a tactical-grade MEMS-based inertial measurement unit and a low-cost MEMS magnetometer. The developed system allows not only to pointing the North direction but also to assure the stability of the attitude estimates overcoming bias and drift errors affecting the measures of this type of sensors and keeping the advantages of the MEMS sensors technology such as small volume, lightweight and flexibility. The proposed integrated solution exploits an indirect gyrocompassing strategy through an error-state Kalman Filter algorithm for the coarse alignment aided by the magnetic Earth field measurements. The system performance is preliminarily assessed in static conditions and compared with a certified reference system in order to verify its compliance with the requirement for Small Unmanned Aerial System.

Accurate Attitude Inizialization Procedure based on MEMS IMU and Magnetometer Integration

This research activity deals with 3D printing composites fabricated by Continuous Fiber/Filament Fabrication with an innovative thermoplastic matrix infilled with microcarbon fiber, i.e., Onyx, and...

Felice Rubino

Papers

On the critical technological issues of CFF: enhancing the bearing strength