Luca\ Sorrentino

• Professor
• Full Professor at University of Cassino and Southern Lazio

The increasing demand for lightweight and sustainable materials in the automotive industry has driven interest in thermoplastic composites reinforced with natural fibers. This study investigates the mechanical behavior of flax fiber-reinforced polypropylene (Flax/PP) laminates, manufactured using a vacuum bagging prepreg process. The laminates were...

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 p...

In recent years, there has been a growing interest in recyclable and eco-friendly materials, driven by the need to develop components with complex geometries, variable thicknesses, and large dimensions, particularly in sectors such as building and automotive. Eco-Sustainable Sandwich Panels (ESSP), which combine lightweight cores with thermoplastic...

Laser sintering, also known as powder bed fusion—laser beam, employs a laser to sinter-powdered polymeric materials, such as Polyamide 12. Despite the process, a significant portion of the powder remains unsintered. However, due to elevated temperatures, material degradation occurs, altering its chemical characteristics. Industrially, a common prac...

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 mecha...

Lattice structures are very interesting since they present good mechanical properties coupled with lightness. Today, the maturity reached by additive manufacturing technologies allows the production of such structures. However, the mechanical properties of the constituting material can be affected by the process itself, because of the particular ge...

We present a comprehensive review of recent techno-economic analyses concerning the recycling of fibre-reinforced thermoset polymers, delving into the strategies employed. Additionally, we offer insights into the critical issues that necessitate consideration when evaluating solutions for valorizing these materials. Our emphasis lies in advocating...

Adopting novel sandwich structures with FRP (Fibre Reinforced Polymer) skins and a metallic lattice core, both of which have high specific strength and stiffness, is one way to achieve better mechanical performance while remaining lightweight. Flexural stress is a load pattern that frequently occurs in the structural frame components of automobiles...

Aluminum has become increasingly important in the automotive sector due to its ability to reduce vehicle weight without compromising structural performance. However, joining different types of aluminum alloys can be challenging due to their different thermal and mechanical characteristics. Concurrently, friction stir processing (FSP) is a material...

Introduction Fast and accurate diagnosis of acute stroke is crucial to timely initiate reperfusion therapies. Conventional high-field (HF) MRI yields the highest accuracy in discriminating early ischaemia from haemorrhages and mimics. Rapid access to HF-MRI is often limited by contraindications or unavailability. Low-field (LF) MRI (<0.5T) can dete...

In this work, the influence of hydrothermal ageing on performances of CFRP single lap bonded joints subjected to two types of pre-treatments was investigated. The first is a degreasing pre-treatment, while the second if a laser texturing pre-treatment through a CO 2 laser system. The study considered the influence of an aggressive environment on ge...

Selective Laser Sintering (SLS) uses a laser to sinter powdered polymeric materials, such as Polyamide 12 (PA12). Industrially, it is commonly used as a mixture of virgin and aged powder. The aged powder has undergone various thermal cycles without being sintered. This work aims to evaluate the differences in the dimensional and geometrical deviati...

Lattice structures made of metal materials are very interesting since their structural efficiency is elevated, thanks to their good mechanical properties and light weight. Additive manufacturing processes are appropriate to produce those structures. However, the peculiar geometry of lattice structures causes the manufacturing process to create rath...

Fibre Metal Laminates (FMLs) are very interesting materials due to their light weight coupled with their high stiffness, high fatigue resistance, and high damage tolerance. However, the presence of the polymeric matrix in the composite layers and of polymeric adhesive at the metal/composite interface can constitute an Achille’s heel for this class...

In this work, for the first time thin, sheets of AA8006 aluminum alloy, that are commonly used for food packaging, were mechanically characterized through an unconventional free-forming technique that was performed at room temperature. This technique constitutes an economically effective solution to determine the constitutive equation of a metal sh...

Powder Bed Fusion (PBF) is a popular additive manufacturing technology due to its high build resolution and ability to produce microscale geometries without the use of additional support. Despite the many benefits of PBF, there are still some limitations associated with the materials to be built. A critical industrial limit is the aging of PA12 pow...

Nowadays polymer composites have found increasing use especially in those areas where high mechanical performance is required with the lowest possible weight. For example, often the parts have complex geometries difficult to achieve with a single forming step, so in the industrial field there is the tendency to make more parts of simpler geometry t...

Sandwich structures, constituted in honeycomb core and skin in composite material, are usually employed to produce parts having a constant thickness or simple shape. Indeed, sandwich components with complex shapes, curvature or varying thickness are costly to manufacture due to the preliminary machining operations required on the core prior the mol...

Metal lattice structures manufactured utilising additive techniques are attracting increasing attention thanks to the high structural efficiency they can offer. Although many studies exist on the characterisation of massive parts in Ti6Al4V processed by Electron Beam Melting (EBM), several investigations are necessary to characterise the Ti6Al4V la...

In this work, a dual objective is carried out on composite materials in flax fiber and bio-based epoxy resin: to determine the process parameters and to develop a numerical model for highlighting the potential of and the limits in the production of “green” laminates through a RIFT process (Resin Infusion under Flexible Tool). For these reasons, com...

Drilling process of fiber metal laminates (FML) requires a proper design of the processing parameters to prevent the occurrence of several issues and minimize defects, which can be detrimental for the integrity of the parts. These aspects become more critical in dry machining used in aeronautic field. In this scenario, the monitoring of process tem...

Lattice structures represent a valuable solution for applications demanding both high mechanical properties and lightweight. However, the skin is required to obtain uniformity of the load distribution and avoid stress concentration. The characteristics of the skin materials can influence the mechanical properties of the structure; therefore, in the...

Drilling operations in fibre metal laminates (FML) require a considerable optimization activity of the machining parameters as a function of those used in drilling of its constituents, fibre reinforced polymers and aluminium alloy. The accurate choice of drilling parameters is essential to minimize any defects of machined surface and inside the mat...

Metal lattice structures produced by means of additive techniques are attracting increasing attention thanks to the high structural efficiency they can offer. In order to achieve the maximum structural performance, numerical design techniques are used almost exclusively, thus based on CAE-FEM codes. Nevertheless, the current manufacturing facilitie...

Surface pretreatment for bonding is one of the most important steps for the manufacturing of a reliable bonded joint. In this paper, the effectiveness of an innovative pretreatment by CO2 pulsed laser for bonding Carbon Fiber Reinforced Polymer (CFRP) was investigated. End Notched Flexure (ENF) specimens were made with different densities of laser...

In the present paper five beam models are presented to reproduce the experimental response of the End Notch Flexure (ENF) test. In particular, a specific ENF scheme is considered; it is made of two symmetric laminates partially bonded by a adhesive layer, whose thickness is not negligible. The failure occurs at the interface between one laminate an...

High performances in terms of mechanical properties and lightweight are increasingly required to materials, and a solution to meet these requirements is the adoption of innovative hybrid structures made of metallic lattice core and composite material skins. In this work, two different processes are analysed and compared: co-curing and bonding. In t...

Lattice structures are very interesting for applications in the aerospace field since they combine high stiffness with lightweight. Moreover, they can constitute the core material for sandwich structures. In this work, the bending properties of two kinds of sandwich structures were compared through experimental activity: both of them had a lattice...

Lattice structures allow achieving high stiffness and strength, maintaining the part weight low. There exist different technologies for the manufacturing of such structures, but the one having high flexibility and offering the possibility of producing parts with complex geometries is the additive manufacturing process. In this paper, titanium speci...

Metal sheet forming is widely used in industrial field. Generally, the use of patchwork banks allows the manufacturing of a more uniform thickness of the formed parts. Often, they are obtained using welding techniques: in these cases, distortions and localized metallurgical transformations could have detrimental effects on the mechanical performanc...

Diamond tools suitable for machining operations of natural stones can be divided into two groups: cutting tools, including blades, the circular blades and the wires, and the surface machining ones, involving mills and grinders, that can be of different shapes. For the stone sawing process, the most adopted tool type is the diamond mill, whose durat...

Purpose Selective laser sintering (SLS) has passed other techniques, thanks to its high print resolution, its ability to print microscale geometries without any additional support, its surface quality and its long-term thermal stability. However, despite the many advantages of SLS compared to fusion deposition modelling, there are still today some...

The structures adopted in the aeronautic field should have three main characteristics: they must be strong, stiff, and light. These targets can be obtained by choosing high performance and low weight materials, as composite or titanium alloy, but also the wise design of the structure itself is important for enhancing the mechanical performances. Th...

Lattice structures are characterized by good mechanical efficiency because their particular geometry confers high strength and stiffness coupled to lightweight. These structures can be produced using a wide range of technologies, but the additive manufacturing ones are the most promising. In this work, the flexural properties of titanium alloy latt...

High levels of stiffness, strength, and lightweight can be achieved through lattice structures. Many different technologies can be adopted for their construction; among them, additive manufacturing presents high flexibility and the capacity to produce complex shape parts. In this paper, a detailed analysis of the fracture surface was carried out on...

The thermomechanical interactions between the different materials constituting a hybrid laminate make residual stresses arise during the manufacturing process of such laminate. In turn, the residual stresses make the laminate deform as it is extracted from the mould. Cure induced deformation represent a problem for the assembly step, since addition...

This paper addresses the application of nature inspired methods to the optimization of resin cure in thick or thin composite laminates. The methodology presented in this work consists in the coupling of artificial neural network with optimization algorithms, focusing on the thermal cycle evaluation that further the progress of the degree of cure (D...

The sheet metal forming operations generally involve the production of parts characterized by a non-uniform thickness distribution. However, in some cases, a product characterized by a distribution of thicknesses that is as uniform as possible may be desirable. This result can be obtained by using multiphase processes or by subtraction or addition...

Surface roughness of the adherends represents an important factor for manufacturing a reliable bonded joint in structural applications. In case of bonding of parts in carbon fibre reinforced polymer (CFRP), an increase of roughness parameters can be obtained with various techniques. In this paper, the morphology obtained from a CO2 laser texturing...

A Fibre metal laminate (FML) consists of a stack of metal sheets alternating to composite material layers: in such a manner, the best characteristics of both constituents are combined together. In this work, the flexural behaviour of different kinds of FMLs was investigated. In particular, both long beam and short beam specimens were produced and t...

Lattice structures are very light and strong, but they need to be wrapped with skin to evenly distribute the loads over the entire surface of the structure. Considering additive manufacturing as a process to produce lattice structures, the easiest way to add the skin is its building together with the lattice core. However, if the core is made of me...

FML (Fibre Metal Laminate) is a hybrid material that presents outstanding structural properties, such as resistance to cyclic and dynamic loads, together with low specific weight. This material consists of metal sheets alternating to composite material layers. In the present work, the ILSS (Interlaminar Shear Strength) was evaluated for different t...

In stone sawing process, the most adopted tool type is the circular diamond blade, whose duration and performance are influenced by various elements. These factors can be grouped into four categories: the mineralogical characteristics of the material to be machined; the working conditions, such as the depth of cut, the feed rate and the cutting spe...

Recently, many studies showed the opportunity to use a CO2 laser for treating the surfaces for structural bonding. In this work, a study on the effectiveness of a laser texturing on ENF bonded joints made with CFRP and epoxy adhesive has been developed. The experimental results showed that the use of this technology allows obtaining mechanical resi...

Fibre metal laminates (FMLs) are a class of hybrid laminates made of composite material plies and metal sheets; they are used for applications where extraordinary mechanical properties are needed, due to their high damage tolerance, low weight, and high strength. In the present work the behaviour of different types of aluminium‐carbon fibres FMLs w...

FMLs (fibre metal laminates) are a kind of hybrid material consisting of composite material layers alternating to metal sheets, that present high mechanical characteristics. The aim of the present work deals with the flexural behaviour of CARALL (carbon fibre-reinforced aluminium laminates) specimens; in fact, the influence of both the layer thickn...

Additive manufacturing (AM), applied to metal industry, is a family of processes that allows complex shape components to be realized from raw materials in the form of powders. Electron beam melting (EBM) is a relatively new additive manufacturing (AM) technology. Similar to electron-beam welding, EBM utilizes a high-energy electron beam as a moving...

In the last decades, structural adhesives have found an increasing use owing to the fact that they, compared to traditional techniques like bolting and riveting, allow more uniform stress in the joint without drilling the parts of the assembly. Moreover, the quality of a bonded joint is strongly linked to the surface treatment used for the adherend...

In the last decades, the combination of high mechanical performances and low production costs increased the industrial interest on ductile cast irons. These grades are often used for applications where the fatigue resistance can be a critical issue (eg, machine frames for the wind‐power industry or crankshaft used in trucks) and the investigation o...

High-flexibility components in composite material are of great interest in many fields, from aeronautic and automotive industries to sport and design goods. Their deformation during cure process, known as spring-in and warpage, is acceptable if it is within the indicated tolerance. The research aim of the present work is to present a way to inspect...

Using a finite element calculation code, this work analyses the influence of friction during a stamping test conducted on the AA6060 aluminium-based alloy. The study focuses on phenomena happening when the sheet necking appears. This condition, based on the Hill�s localized necking theory and the Swift�s diffuse necking theory, is dependent on the...

Industry needs new materials that present very high structural characteristic, such as high strength, low weight and high damage tolerance. To obtain these characteristics a new class of materials has been introduced: Fibre Metal Laminate (FML); they consist in metal sheets alternated to composite material layers: in such manner, the good character...

In recent decades, designers have increasingly focused on the stability of assemblies in composite materials over time, particularly when used in structural applications. The use of structural adhesives allows for realising assemblies without mechanical fasteners. In fact, bonding is an assembly technique that prevent corrosion, ensures uniform str...

The robotic filament winding (RFW) technology consists of an industrial robot that is equipped with a feed and deposition systems; they are suitable for placing a tape along the stress directions the part is subjected to during operation. RFW cell replaces the human operator that is the only system that has been previously used to manufacture compl...

Fibre metal laminate (FML) is a material constituted by composite laminae and metal sheets, whose mechanical properties can be tailored by varying the thickness and the number of layers. For this reason, in the present work different types of FML made of carbon fibre reinforced polymer and aluminium sheets were produced and tested; in particular, t...

Duplex Stainless Steels (DSSs) are an attractive class of materials characterized by a strong corrosion resistance in many aggressive environments. Thanks to the high mechanical performances, DSSs are widely used for many applications in petrochemical industry, chemical and nuclear plants, marine environment, desalination etc. Among the DSSs critic...

Very high mechanical properties, such as high strength, high damage tolerance and low weight, can be reached by coupling composite laminae and metal sheets: in such a manner a new material is obtained: the Fibre Metal Laminate (FML). The diversification of the thickness and the number of layers is suitable to change the structural properties. In or...

High mechanical characteristics, such as impact and fatigue resistance, coupled with low weight can be obtained combining metal sheets and composite laminates; in this way a new hybrid material is obtained: the FML (Fibre Metal Laminate). In the present paper, an analysis of the influence of both composite/metal interface and layer thickness on ILS...

Nowadays composite materials play a leading role in structural design, particularly in aeronautics and automotive. In these industries, to reduce the weight of the components maintaining the same performance is most required. With this in mind, the use of structural adhesives allows to maximize the specific strength of assembled parts. To have a th...

Natural stone is a material that presents durableness over time and high aesthetic characteristic, but it is brittle and its tensile strength is significantly lower than compressive one: these peculiarities must be taken into account for material usage; in fact, for applications requiring high flexural and tensile strength, as thin sections or long...

Lightening parts, maintaining also a high strength, is a request of the transport industry. Isogrid structures represent one of the best answer to face these issues, especially if composite materials are considered for their production. However, the fabrication of these structures is very complex, as defects can arise that cause the part discarding...

This article addresses the optimization of curing process for thick composite laminates. The proposed methodology aims at the evaluation of the thermal cycle promoting a desired evolution of the degree of cure inside the material. At the same time, temperature overshooting as well as excessive temperature and cure degree gradient through the thickn...

During the cure process, the anisotropic characteristics of composite material, combined with high temperature and high pressure to which the material is subjected, cause the development of residual stresses. Consequently, laminate deformations arise and dimensional and geometrical requirements are not reached. Laminate deformations transfer into p...

Electron Beam Melting (EBM) is one of a few Additive Manufacturing (AM) technologies capable of making full-density functional metallic parts. In particular, the ability of direct fabrications of metallic parts can accelerate product designs and developments in a wide range of metallic-part applications, especially for complex components, e.g., fin...

This work analyses the results of a simple forming process of an AA6060 aluminum alloy sheet in order to validate the development of a simulation model based on the finite element method (FEM). This work represents the starting point of a broader study aimed at analyzing the sheet formability. The FEM based model and the use of both the flow stress...

Nowadays adhesives are widely used in structural applications, in particular for assembly composite materials. In fact, this technique allows to obtain a more uniform load in the joint, to realize a joint with a higher specific strength and to avoid drilling parts as in the case of bolted joints. However, the mechanical properties of bonded parts o...

The phenomena that happen during the cure process of a composite material laminate are responsible for the rise of residual stresses and, consequently, for the deformation at the end of the manufacturing process. The most analyzed deformation is the spring-in, that represent the flange-to-flange angle deviance from the theoretical value. In this wo...

The thermochemical and the thermomechanical phenomena that happen during the cure process of a composite material laminate are responsible for the rise of residual stresses and, consequently, for the deformation at the end of the manufacturing process. In this work, the influence of some parameters, such as the laminate thickness, the stacking sequ...

Composite materials are increasingly being used in various field of engineering interest over recent decades. As an alternative to fastening, bonding is one of the most promising assembly techniques of composite materials since it allows a uniform distribution of forces, it has a greater ability to dampen vibration and it does not raise any problem...

Assembling of parts made of composite materials is often obtained by bolted or riveted joints. Therefore, drilling is one of the most common machining operation for composite laminates. However, this process causes some kinds of damage on the laminates, as delamination; the aim of this work is to reduce the delamination of the laminate. First of al...

During the cure process of CFRP laminates, some geometrical unconformities can arise, due to several thermomechanical and thermochemical phenomena that make residual stress rise. Among these unconformities, one of the most studied is the spring-in, that is the deviation of the flange-to-flange angle from the design value. In this work a numerical m...

Machining of carbon fibre reinforced polymers is an important step for the integration of advanced materials into engineering applications. Machining damage due to excessive cutting forces may cause the rejection of the composite components at the final stages of their production cycle. The cutting forces are related to the surface finish and tool...

Drilling is the most important machining operation applicable to polymeric composite materials since it is essential for mechanical coupling of parts. Drilling process provokes several issues, including localized thermal shock, caused by the presence of abrasive and extremely hard fibres and the low thermal conductivity of composite, which restrict...

Among machining operations applied to polymeric composite materials, drilling is the more important one due to the need to implement mechanical couplings, which in most cases are not yet possible using structural adhesives. Such process is very critical because not only it causes the interruption of the fibers continuity, but also it can generate l...

Stone are usually cut by diamond wire, that is frequently used to square stone blocks in marble companies and to pull blocks out of quarries. The diamond wire machines used for carrying out the former task are afflicted with a lot of technological troubles, such as poor surface finishing, low efficiency (in comparison with diamond wire machines use...

Aeronautical and aerospace industries require light and robust structures. This target can be achieved designing isogrid structures made of composite material. In fact, such structures present both lightness and structural resistance. However, some problems can arise during the manufacturing process of these structures. In the present work the RFW...

During the curing process, the exothermic cross-linking reaction inside epoxy resin-based composites causes overheating and, eventually, a thermal degradation of the matrix. Thick sectioned epoxy composites require an optimized curing cycle in order to minimize the temperature raise inside the composite. However, the recommended cycle for thin lami...

The machining of fibre reinforced composites is an important activity for optimal application of these advanced materials into engineering fields. During machining, any excessive cutting force has to be avoided in order to prevent any product reject in the last stages of production cycle. Therefore, the ability to predict the cutting forces is esse...

The curing process of thermosetting resins plays a key role on the final quality of the composite material components. Soft computing techniques proved to be an efficient method to control and optimize the curing process, replacing the conventional experimental and numerical approaches. In this paper artificial neural network (ANN) and fuzzy logic...

The production process of fiber-reinforced plastic parts must be controlled through sophisticated instruments to warrant high quality standards. The cure degree of matrix, which is representative of the product quality, is in general evaluated by an indirect method, measuring the temperature inside the laminate, or by a direct method, evaluating th...

Polymeric composite parts are often manufactured with thin laminates and the manufacturer's recommended cure cycles are usually optimized for a less than 5 mm thickness. However, sometimes manufacturing thick laminates is necessary for structural applications: in this case, the manufacturer's cycle is not suitable as it can produce a peak of temper...

The diffusion of prepreg composite material parts is hampered by high cost of both raw material and manufacturing process. As for this latter, it is due to the manual ply-on-ply layering carried out by skilled workers. A technology that can be used to preform prepreg plies on the mould is Hot Drape Forming that is a particular thermoforming process...

Isogrid structures are constituted by a thin skin reinforced with a lattice structure. Such structures are adopted in aeronautical industry since they present both structural resistance and lightness. These structures were initially made of aluminium and were obtained by milling process. Nowadays, composite materials are used in order to improve th...

Machining operations are frequently used in the manufacture of fibre-reinforced plastics parts as a corrective operation to produce well-defined, high-quality surfaces that often require the removal of excess material to control tolerances.

Using the finite element method, this paper analyzes the superplastic flow of PbSn60 alloy submitted to free bulging test. The value of H (defined H*) corresponding to the maximum value of dt/dH is also analyzed. The dependence of H* from the die and the sheet geometry, the process parameters and the material constants is showed. Free bulging tests...

This work intends to establish, by means of analytical modelling, a practical definition of the superplastic behaviour by using the results of the free bulging of sheet metal instead of the results of the traditional tensile test. In particular this paper analyses the superplastic flow of PbSn60 alloy and it focuses the attention on the value of H...

The cure degree must be as uniform as possible during the manufacture cycle of polymer–matrix composite laminate to obtain parts without defects. Thermal cycle recommended by technical sheet is usually suitable for thin components, so its redesign is necessary to solve unconformities for thick laminate parts, which usually show these problems. In t...

Low mechanical resistance and high weight restrict use of natural stones in applications where tensile or flexural capacity is required together with a low weight, such as for long spans or thin sections (e.g., cladding, countertops, desktops). The use of composite laminates as external reinforcement both to increase the mechanical resistance and t...

Composite materials are increasingly used for advanced applications subjected to high standards of quality that can be guaranteed by sophisticated control systems of the production process. Quality is usually controlled by monitoring temperature inside the laminate, but some researches have also evaluated the degree of cure during the thermal cycle...

The machining of fibre reinforced composites is an important activity for optimal application of these advanced materials into engineering fields. During machining any excessive cutting forces have to be avoided in order to prevent any waste product in the last stages of production cycle. Therefore, the ability to predict the cutting forces is esse...