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Functionally graded materials raise considerable interest in the biomedical research. In particular, gyroid structures are suitable for bone tissue engineering applications, allowing to emulate the porosity of the inner part of the bone. In this frame, the mechanical properties of 17–4 PH steel gyroids made by additive manufacturing have been investigated. Three design methods have been implemented, i.e., thickness graded, size graded, and uniform, to address the lack of knowledge in the area of stainless-steel scaffolds aiming at providing a map of the mechanical properties. Compressive mechanical properties absorbed energy and absorption efficiency have been found for the aforementioned design methods. Furthermore, defects and collapse behavior have been analyzed: imperfections have been detected in the thin-walled areas of the graded samples. Nevertheless, under given conditions, the graded samples have mechanical properties comparable to those of uniform ones, exhibiting a controlled layer-by-layer collapse mechanism and consequent weight reduction. The Gibson-Ashby models have been implemented, and the calibration coefficients have been compared with other research works. A FEM-based numerical model has been proposed to reproduce the mechanical properties of the mentioned structures finding critical issues in the representation of defects. In this frame, the resulting Gibson Ashby calibration coefficients are in good agreement with the literature and reveal the graded samples have a bending-dominating behavior sustaining larger strains than the uniform case, giving the ground for high energy absorption applications. Furthermore, the FEM analyses are in good agreement with the literature providing a reliable tool to further investigate the metal functionally graded gyroid field.

Barcelona, Spain

This work investigates the application of the CO2 laser cutting process to three thermoplastic polymers, polyethylene (PE), polypropylene (PP), polycarbonate (PC) in different thicknesses ranging from 2 to 10 mm. The process parameters examined were: laser power, range of cutting speed, type of focusing lens, pressure and flow of the covering gas, thickness of the samples. Furthermore, the values of kerf widths on top (Lsup) and bottom (Linf) thicknesses, the melted transverse area, the melted volume per unit time and surface roughness values (Ra) on cut edges were also measured.

A cold plasma prototype electrode discharge apparatus to perform polymer surface treatment is described. The plasma generator, operating with oxygen and/or nitrogen, works in glow regime at low pressure (10 mbar) and at relatively high gas flow rate, in the 110–340 1/h range. The effects of treatments on PET monopolyester and glass fibre reinforced plastics (GFRP) surfaces are analysed. The treatment points out, in all operating conditions, an increase of both wettability (PET) and adhesivity (GFRP). The treatment times obtained are one order of magnitude lower than those of the traditional treatment apparatus.

The aim of this paper is to apply, in the simulation of a Flexible Manufacturing System (FMS), a statistical methodology that enables to evaluate the level of control factors, at low economical impact, that yields an optimal response. The methodology adopted to realise this objective is the Design of Experiment (DOE) applied to discrete event simulation. The analysis of the result is carried out by using the Analysis of Variance (ANOVA).