Giuseppe Moffa

Adhesive bonding is increasingly used in lightweight structural applications, though its effectiveness for carbon fiber reinforced polymers is often limited by low surface energy. This study investigates the concurrent effect of infrared laser surface texturing and resin pre-coating on the mechanical performance of carbon fiber-reinforced polymer single-lap joints. Using a CO ₂ laser system, micro-dimples were generated on the substrate to promote mechanical interlocking, while various concentrations of an epoxy resin (5 wt%, 10 wt%, and 20 wt%) were applied as precoating to enhance surface wetting and interfacial continuity. To validate the experimental findings, a numerical investigation was performed using a Cohesive Zone Model implemented within a finite element framework. This model utilized a bilinear traction-separation law and a quadratic delamination criterion to predict the progressive debonding and failure of the interface. Experimental results indicate that the 10 wt% resin pre-coating concentration provides the highest lap shear strength.

This study investigates the influence of different surface treatments (namely, mechanical abrasion and solvent cleaning with isopropyl alcohol and acetone) on the adhesive bonding performance of polylactic acid (PLA) substrates produced by Fused Deposition Modeling (FDM). Pull-off tests revealed that the isopropanol-cleaned specimens achieved the highest bond strength, with an average pull-off value exceeding 8.5 MPa, compared to approximately 5.6 MPa for untreated PLA. Conversely, acetone cleaning resulted in the lowest performance (about 3.5 MPa), while mechanical abrasion yielded intermediate values of about 6 MPa. FTIR analysis confirmed that no chemical reactions occurred, although acetone and abrasion induced significant physical surface changes, unlike isopropanol, which acted as an effective cleaning agent. These findings demonstrate that surface cleanliness plays a dominant role over morphological alterations in enhancing the adhesion of PLA-based 3D-printed joints.

This work investigates the role of friction in the numerical prediction of formability for ultra-thin aluminum sheets made of the EN AW 8006-O alloy. Nakazima-type hemispherical punch stretching tests were conducted under lubricated conditions to assess the influence of interface tribology on thickness distribution and failure behavior. The experimental activity included tensile testing for material parameter identification and coefficient of friction (COF) measurements according to ASTM D1894 to characterize interface friction. These parameters were then implemented into a finite element model developed in PAM-STAMP. The simulation results were compared with experimental thickness profiles, and showed good agreement when calibrated friction coefficients were used. The analysis highlights the sensitivity of sheet deformation to frictional conditions, and demonstrates that accurate tribological input significantly improves predictive accuracy. The proposed workflow offers a reliable and efficient methodology for simulating forming processes involving ultra-thin aluminum foils, with potential applications in the food packaging industry.

Fused Deposition Modeling (FDM) has emerged as one of the most widely adopted additive manufacturing (AM) technologies due to its broad material availability and low production costs, enabling the efficient production of complex geometries and customized components. Among the materials commonly used in AM, Acrylonitrile Butadiene Styrene (ABS) is particularly notable for its favorable mechanical properties, ease of processing, and versatility. While moderate-to-high-density lattice configurations have been extensively studied, low relative density lattice structures remain largely unexplored. This study investigates the feasibility of fabricating Cuboidal Body-Centered Cubic (BCC) lattice structures with relative densities of 5%, 10%, and 15% using FDM. The geometrical/dimensional accuracy of the printed samples is thoroughly assessed to quantify fabrication-induced deviations, focusing on strut geometry and overall lattice consistency. Results show that while smaller lattice configurations, particularly those with 5% relative density, exhibit significant geometrical inaccuracies due to printing limitations (e.g., strut waviness, material deposition inconsistencies, layer misalignment), larger configurations demonstrate improved dimensional and geometrical fidelity and structural integrity. A framework is proposed for assessing geometrical/dimensional fidelity, which can enhance the predictive modeling of these structures and optimize manufacturing processes. These findings clarify low relative density lattice manufacturability, guiding research on mechanical performance for lightweight aerospace applications.

The widespread use of synthetic composite materials has raised environmental concerns due to their non-biodegradability and energy-intensive production. This paper explores the potential of natural composites, specifically flax–polypropylene, as a sustainable alternative to traditional composites for semi-structural applications. In fact, the mechanical properties of flax–polypropylene composites are similar to synthetic ones (such as those made with E-glass fibers). However, processing challenges related to fiber–matrix interaction and material degradation necessitate suited process parameters for this sustainable type of material. For this reason, this review highlights the importance of optimizing existing manufacturing processes, such as hot press molding, to better accommodate the specific characteristics of polypropylene–flax composites. By refining the parameters and techniques involved in hot press molding, researchers should overcome current limitations and fully capitalize on its potential to produce composite materials of optimal quality. Therefore, a comprehensive literature assessment was conducted to analyze the properties and processing challenges of flax–polypropylene composites. Key process parameters affecting the material’s performance are identified and discussed. By optimizing process parameters for flax–polypropylene composites, it is possible to develop a sustainable and high-performance material with a reduced environmental footprint. Further research is needed to scale up production and explore different applications for this sustainable composite material.