Geometric modeling and processing

The Radial Neutron Camera is an ITER diagnostic designed to measure the un-collided 14 MeV and 2.5 MeV neutrons from deuterium-tritium (DT) and deuterium-deuterium (DD) fusion reactions, through an array of detectors covering a poloidal plasma section along collimated Lines Of Sight (LOS). It is composed by two fan-shaped collimating structures viewing the plasma radially through vertical slots in the diagnostic shielding module of ITER Equatorial Port 1: the In-Port RNC, devoted to plasma edge coverage, and the Ex-Port RNC, devoted to the plasma core coverage. This paper presents an overview of the mechanical design of the Ex-Port RNC at the Preliminary Design Review (PDR) stage. The Ex-Port RNC is located in the Port Interspace and consists of a massive shielding structure hosting the detector units and two sets of collimators lying on different toroidal planes. The Ex-Port RNC design is presented both from the point of view of functional requirements (e.g. LOS positions and angles, radiation shielding, weight limitations) and of manufacturability. Finally, the Ex-port RNC structural integrity is assessed, and its design validated against the main loads and load combinations.

Keywords: Design description , Ex-Port , Finite element method , ITER , Radial neutron camera , Structural integrity

One of the main challenges for the construction of DEMO, the first fusion demonstration reactor, is the power exhaust issue. To deal with it, EUROfusion has undertaken the construction of DTT (Divertor Tokamak Test) facility which will be held in Frascati, Italy. It aims to test various divertor models which can be integrated and used under different plasma confinement configurations. The current design of DTT embed 54 divertor cassettes which must be anchored to the vacuum vessel using suitable fixation systems. This paper deals with the initial monotonic load assessment of the fixation system of the Fixation System which must ensure compliance with multiple design requirements. The Remote Handling compatibility is one of the most demanding, since it includes a preloading phase of the divertor necessary to mitigate the shaking of the cassette due to dynamic forces. Moreover, the system must withstand the conspicuous loads acting on the Divertor due to the full or partial loss of plasma confinement (Disruptive Events). Structural verifications through Finite Element Method (FEM) have been performed on the Divertor-Fixation System, considering a set of load combinations, with particular focus on the most demanding case related to Fast-transient Vertical Disruption Event-downward.

Keywords: Concept design , Divertor , DTT , FEA

The Radial Neutron Camera (RNC) is an ITER diagnostic system devoted to the radial measurement of the plasma neutron emissivity during ITER operation. In particular, plasma core measurements will be performed using 48 detectors located in the Ex-Port RNC subsystem and viewing the plasma through 16 lines-of-sight (LOS). Since discrepancies concerning the position of the LOS and the related optical path can occur during RNC installation and ITER operation, a Position Monitoring System (PMS) is foreseen to evaluate the misalignment and provide a correction tool for the neutrons count rate. During the design of the PMS for the RNC, optic fiber-based displacement sensors have been identified as the best solution to measure the displacements from reference positions along the radial, vertical and toroidal directions. Potential issues that could arise during the installation and operation of such sensors have been evaluated; MCNP calculations have been performed to determine the radiation level at the position of the PMS components. Finally, mechanical tests have been carried out at ENEA to evaluate the performance of the sensors: results indicate compliance with the specifications provided by the producer and the ITER RNC design requirements.

Keywords: ITER , Position monitoring system , Radial neutron camera

The engineering design phase usually requires the integration of different types of studies and analyses for the definition of the whole system. Depending on their nature, these studies can be carried out thanks to specific FEM models and tools which differ from each other on the basis of the physics problem under investigation. A proper methodology for integration of different analyses is needed, in order to transfer information and integrate the multi-physics issues. The aim of this paper is to present a methodological framework supporting the analyses integration process and the results assessment. Based on a CAD-centric approach, the framework is applied in the software Ansys Workbench, to show how to deal with this problem in such tool, thanks to the Import Load function. A study case is considered in the nuclear fusion research field: multiphysics analysis on DEMO divertor, where several physics interact with each other due to the relevant complexity of such systems. In this study, force results from FEM EM analysis are imported into the structural analyses, in order to evaluate the effect of such loads on the cassette structure. Problems dealt with concern the difference of meshes' specifics and the varying of load interpolation settings.

Keywords: Data transfer , DEMO divertor , FEM analysis , Loads interpolation , Multiphysics analysis

The development of a viable maintenance strategy for the replacement of the Breeding Blanket (BB) segments of DEMO is a key aspect in the way for fusion energy. Previous work concerned the development of a BB vertical transporter to lift, tilt and handle the BB segment inside the remote handling (RH) ports. A potential solution for the replacement of the BB segments could consist in lifting all BB segments from four RH ports, by mean of BB vertical transporter coupled with a BB toroidal in-vessel transporter avoiding the opening of the remaining ports during maintenance. In this way, the activities concerning the removal and re-installation of the auxiliary components (BB feeding pipes, permanent structure for pipes handling, closure plate, port plug, etc.) inside the non-remote handling ports will be avoided, having a strong impact on the reduction of the remote maintenance times and hence on the overall availability of the machine. To assure the feasibility of the proposed strategy a dedicated tool, capable to move toroidally the huge BB segments, shall be developed. The main function of the tool will consist in lifting and toroidal translation of the BB segments that have to be aligned to the RH port, where they will be grabbed and lifted by the BB vertical transporter. The work here presented focuses on the conceptual design of a toroidal transporter to lift and toroidally translate the BB segments inside the Vacuum Vessel. The conceptual design of the BB Toroidal Transporter (BBTT) was developed to handle both the inboard and the outboard segments; a foldable lower foot, equipped with toroidal trucks and suspension system, has been designed to withstand the assumed loads and seismic loads. Preliminary FEM analysis has been carried out to check the structural integrity of the proposed design.

Keywords: Breeding blanket , CAD , DEMO , FEM , Remote maintenance

This paper aims to highlight the importance of Computer-Aided Design (CAD) model integration within multi-domain modelling activities. Information about geometrical system size is generally lost in a multi-domain numerical model that focuses on simulating the interactions among different physical system parameters during their operations. For this reason, the present paper proposes a multi-domain modelling approach that uses both geometrical and numerical models to study the behavior of a battery electric vehicle (BEV) energy storage system (ESS). In particular, the numerical model is aimed to simulate thermo-electrical ESS behavior in MatLab/Simulink environment while the geometrical CAD model supports the design activities of different battery cells layout using SolidWorks Dassault software. The objective of this integrated model is to compare the Battery Pack (BP) hotspots of the different designed layout solutions obtained. In conclusion, four different layout solutions have been proposed and compared with some evaluations related to their geometrical size, to test the effectiveness of this multi-domain instrument.

Keywords: Computer Aided Design , Electrical Vehicles , Lithium-ion , Multi-Domain Modelling , Top-down approach

Earth-moving machine builders require innovative design methods and tool to optimize structural performance while reducing production and design costs, particularly in crucial phases like undercarriage frame design and structural verification. After an in-depth description of the design flow normally followed in industry, the paper presents a computationally efficient method and tool to aid designers in dimensioning extendable tracked undercarriages, aiming to drastically reduce design time and efforts to optimize resources. The proposed tool is based on an analytical model established from in-depth analyses of the undercarriage Computer Aided Design (CAD) assembly and the expertise of the industrial partner. To address the 3D structural problem, a planar system is employed with proper corrective coefficients. These coefficients are meticulously evaluated through direct comparison with Finite Element Method (FEM) models by seamlessly integrating SolidWorks and ANSYS Workbench. The tool accepts as inputs geometric and material data, as well as specific user-defined load scenarios, providing outputs in the form of the deflected configuration of the undercarriage and stress levels. Direct comparison with the results obtained from FEM for three industrial undercarriage models demonstrates the validity of the approach, with errors consistently within the 10% range in almost all cases. This enables designers with no advanced skills in FEM to efficiently validate diverse design variants with minimal effort. Once validated, the tool is integrated with an optimizer in Matlab to conduct computationally efficient design optimization studies. The optimization problem, focused on minimizing the beam's vertical size while maintaining structural integrity and limiting deflections, has been successfully resolved within a limited computational time, showcasing the benefits of the proposed approach for undercarriage design.

Keywords: CAD/CAE integration , Earth-moving machinery , Engineering design tool , Structural design , Tracked undercarriage

Additive manufacturing technologies spread widely in multiple scientific sectors thanks to their flexibility and property customisation. However, many aspects must be studied further since multiple factors such as their microstructure and internal defects can drastically change the overall mechanical behaviour of the final products. In this work, the stress-strain behaviour of a Selective Laser Melting AlSi10Mg alloy is retrieved through a homogenisation approach with FEM analyses using the Representative Volume Element approach. To this purpose, an in-house code has been developed to model a random spatial pore distribution inside the RVE according to literature references and to impose the periodicity boundary conditions. Results are presented at different overall porosities.

Additive manufacturing (AM) technologies are gaining widespread adoption across multiple engineering sectors due to their ability to create customised components with tailored mechanical properties and reduced material waste. This work presents different innovative Finite Element Method (FEM) models to characterise the behaviour of AM structures. A numerical model is presented to characterise AM porosity defects using the Representative Volume Element (RVE) concept; additionally, different unit cell approaches to study the behaviour of lattice structures are presented. The procedures and methodologies presented offer a range of tools, each with different trade-offs between accuracy and computational cost

Keywords: Additive Manufacturing , FEM , Lattice

ynchronizers are mechanical devices used in gearboxes for braking the fastest shaft up to the angular velocity of the slowest one before engagement. Nowadays, many dual-clutch transmissions include an increasing number of gears in order to improve vehicle performance. However, they still use established and stable solutions for the synchronizers, counting a large number of parts to be manufactured with tight tolerances, and wide axial dimensions. So, the reduction of the synchronizer length is an important goal for the design of new gearboxes with a larger number of gears. The present research work studies a new solution for a shorter and simpler synchronizer. The main innovation is that the traditional conical clutch is replaced with a plane clutch including dog teeth, so that one part is performing both tasks of synchronization and engagement. The present paper discusses a first attempt dimensioning of the synchronizer in order to evaluate its feasibility. The layout was developed interactively with conceptual CAD models for representing the functionality of each element and with 3D printed prototypes in an electro-actuated test rig. This new synchronizer mechanism can be used in new dual-clutch transmissions, with electro-mechanical actuation and possibly with additional speed sensors.

Keywords: Conceptual Design , Functional Decomposition , Gearbox Synchronizer , Systematic Design

In recent years, additive manufacturing has been expanding rapidly in several sectors, including marine, aerospace and civil, offering broad design freedom and environmental/ecological advantages for the production of fully functional products. Particularly in the biomedical area, interesting manufacturing methods have recently been developed for the customisation of orthotic devices by automating the acquisition process and 3D printing. Today, in the development of complex geometries, it is necessary to meet certain design specifications, such as mechanical strength, surface finish, light weight, breathability and aesthetic appearance, which can potentially be met by manufacturing with 3D printers. This research deals with the development and implementation of organic bioplastic compounds based on polylactic acid (PLA) and organic by-products for additive manufacturing applications of customised orthotic parts. PLA, filled with reinforcements and additives, can be used to produce durable and functional parts for improved structural performance. By studying specific orthotic cases with CAD-CAE techniques, its potential mechanical properties will be evaluated and compared to highlight its performance comparable or even superior to that of classical PLA. The proposed methodology reduces production costs and environmental impact. Thanks to the presence of reinforcements and additives, the new organic bioplastic compounds are more biodegradable, while improving some of the functionality and comfort requirements of customised orthoses.

Keywords: biodegradability , biomedical orthosis devices , mechanical properties characterization , Organic bio-composite filament , Reverse Engineering

This paper will focus on two possible optimizations for a novel wrist exoskeleton. Exoskeletons are structures designed to support human joints using mechanical components and are used in various fields such as rehabilitation, military, and industrial sectors. The study focuses on a new exoskeleton for the wrist with the intention of optimizing its weight and mechanical strength. Two optimization methods are employed. the first one aims to achieve traditional optimization using Computer-Aided Design (CAD) and Finite Element Method (FEM) analysis. In the second the use of Generative Design (GD) optimization, which combine topological optimization and Artificial Intelligence (AI), wants to create new organic components almost impossible to obtain without using this tool. The results indicate that GD optimization significantly reduces maximum displacement while maintaining stress levels within material limits, often improving the weight of the part. Moreover, GD optimization streamlines the design process, offering quicker iterations than traditional methods. This study highlights the efficacy of GD in achieving superior exoskeleton designs with improved mechanical properties and reduced weight, presenting it as a valuable tool for designers seeking optimal solutions in less time.

Keywords: Exoskeleton , FEM analysis , Generative Design

Pectus Excavatum is the most common form of thoracic deformity, characterized by the depression of the anterior chest wall. The most widely used non-surgical treatment involves the daily application of the Vacuum Bell, an external medical device that uses negative pressure to lift the sternum outwards. Nevertheless, the Vacuum Bell is only available in four sizes, making it difficult to apply to all possible cases of deformation. In addition, the variability of the surface to be treated and prolonged use can make the application uncomfortable, leading to decreased compliance and treatment discontinuation, thus compromising its effectiveness. In this context, the study was conducted with the aim of producing customized Vacuum Bell models. Starting with the 3D scanner acquisition of the patient, it was possible to reconstruct the three-dimensional model of the chest. Therefore, a specifically implemented MATLAB script enabled the identification of the surface to be treated and the semi-automatically drawing of the 3D curve outlying the deformation. Using this curve, via CAD software, it was then possible to proceed with the modelling of customized Vacuum Bells, whose profile adapts to the specific conformation of the patient's chest. Finally, a Vacuum Bell prototype was realized using additive manufacturing techniques.

Keywords: Additive manufacturing , Customized devices , Pectus Excavatum , Vacuum Bell

As a class of compliant mechanisms that derive their motion from the deflection of flexible members, spherical compliant joints offer frictionless displacement, compactness, and improved precision compared to their rigid counterparts. Among these, tetra joints have gained significant attention in recent years. A novel approach for modeling and analyzing tetra joints, that is challenging due to their special geometry, is presented in this study. An efficient geometric model for streamlined tetra joint modeling, utilizing a Computer-Aided-Engineering (CAE) framework in COMSOL Multiphysics, is introduced. Through detailed discussions, the generation of tetra joint's geometry and the development of a parametric model are elucidated. Additionally, guidelines for constructing the finite element model of the joint and defining relevant boundary conditions are provided. To demonstrate the applicability of the proposed model, two critical parameters of tetra joints are analyzed: the vertical position of the remote center of rotation and the joint's height. The results highlight the significant influence of the vertical position of the remote center of rotation on the joint's mobility, indicating that proximity to the top face of the tetrahedron leads to increased rotation. Conversely, variations in the joint's height have a less pronounced effect on resulting rotations.

Keywords: Compliant Mechanisms , Parametric Model , Spherical Joint , Tetra Joint

Retrievals of small and medium scale are one of the fundamental and most numerous parts of the entire museal heritage set. Their exposition represents an issue, looking for supporting structures that could be non-invasive, aesthetically pleasant, customized, and, last but not least, safe and stiff enough to avoid any damage to the artifacts. Through the usage of several engineering methods, starting from the retrieval and the exhibition requirements, optimized supporting structure can be developed. The procedure here reported and applied starts from the Reverse Engineering acquisition in order to obtain the 3D model of each retrieval, also comprehending color and texture information. After that, exhibition and preservation requirements, given by heritage experts, are translated into engineering requirements, with the usage of an immersive Virtual Reality environment. With these inputs, the developed Generative Design Method (GDM), using CAD, CAE and optimization tools synergically, can optimize the configuration of supporting interfaces with the artifact and then can generate a lightweight conceptual design through a generative design process. In this way, we can take into account all the given requirements, obtaining a lightweight support, topologically optimized, highly customized, non-invasive, possibly pleasant, able to resist in safety, and additively manufacturable. In this paper, the procedure is applied on different retrievals from Museo Civico dell'Agrocimino of Soriano nel Cimino, Italy, with different scales and materials, proving the robustness of the method.

Keywords: Cultural Heritage , Generative Design , Parametric Optimisation , Reverse Engineering , Virtual Reality

The integration of structural optimization into product design processes has been a focus of extensive research, leveraging advances in computing technology to embed numerical techniques within simulation-driven approaches. Topology optimization, particularly enabled by Additive Manufacturing, has emerged as a powerful tool for generating structurally efficient geometries. However, practical implementation poses challenges, often requiring manual redesign and interpretation of results. To address these issues, this study explores the potential of numerical optimization techniques, specifically parametric and shape optimization, to refine topology optimized structures automatically. The final aim is to develop a systematic workflow integrating these tools to produce ready-to-print geometries with minimal user intervention. The investigation, based on simple geometries resembling topology optimized structures, investigates the tools for simulation-driven design methods utilizing multi-step numerical optimization within an integrated CAD platform, aiming for a direct, efficient, and mathematically-driven design process. Advantages include faster iterations, reduced errors, and independence from user expertise, while challenges such as computational complexity, sensitivity to initial conditions, and need for specific design expertise are acknowledged. The potential further systematic approaches for broader applications, particularly in additive manufacturing and structural engineering, underscore the significance of further research in this area.

Keywords: Computer Aided Engineering , Design for Additive Manufacturing , Design Method , Design Optimization , Finite Element Method

CAD-to-XR is the workflow to generate interactive Photorealistic Virtual Prototypes (iPVPs) for Extended Reality (XR) apps from Computer-Aided Design (CAD) models. This process entails modelling, texturing, and XR programming. In the literature, no automatic CAD-to-XR frameworks simultaneously manage CAD simplification and texturing. There are no examples of their adoption for User-Centered Design (UCD). Moreover, such CAD-to-XR workflows do not seize the potentialities of generative algorithms to produce synthetic images (textures). The paper presents a framework for implementing the CAD-to-XR workflow. The solution consists of a module for texture generation based on Generative Adversarial Networks (GANs). The generated texture is then managed by another module (based on Shrinkwrap modelling) to develop the iPVP by simplifying the 3D model and UV mapping the generated texture. The geometric and material data is integrated into a graphic engine, which allows for programming an interactive experience with the iPVP in XR. The CAD-to-XR framework was validated on two components (rifle stock and forend) of a sporting rifle. The solution can automate the texturing process of different product versions in shorter times (compared to a manual procedure). After each product revision, it avoids tedious and manual activities required to generate a new iPVP. The image quality metrics highlight that images are generated in a “realistic” manner (the perceived quality of generated textures is highly comparable to real images). The quality of the iPVPs, generated through the proposed framework and visualised by users through a mixed reality head-mounted display, is equivalent to traditionally designed prototypes.

Keywords: Artificial Intelligence , CAD-to-XR , Extended Reality , Generative Adversarial Networks , User-Centered Design , Virtual Prototyping

The water-cooled divertor design is characterized by features and layout, which are common to several fusion tokamak devices. Pressurized water is used to exhaust power and cool down vertical targets where the strike point of the plasma legs is located, and the Cassette Body Water has many advantages over Helium as a coolant with excellent heat transfer properties, abundant resources and extensive application experiences in both fusion experimental devices and fission reactors. In this chapter the following points will be discussed for the water-cooled divertor option: Divertor architecture design; Plasma facing components; nuclear behavior; thermo-hydraulics; Safety.

Keywords: Cassette body , CuCrZr , DEMO , EUROFER9 , ITER , Plasma facing components , Reduced-activation ferritic/martensitic (RAFM) steel , Tungsten monoblock , Tungsten plasma spray , Vertical targets , Water-cooled divertor

Injuries to the anterior cruciate ligament (ACL) are common among active populations. The shape and anatomical variations of the bones are directly related to the function of the ACL, and therefore are considered to be risk factors for injury. This research aims to delineate the key patterns of shape variation in femurs affected by ACL injuries through the application of Statistical Shape Modelling (SSM). SSM is applied to 50 distal femur models and their modes of variations are described. Ten morphologically significant parameters of the distal femur bone are selected and measured on a 3D model of the mean femur, as well as the -3SD and +3SD shapes of the first three principal components (PCs). The first principal component reflects the variation in size of the femur. The second principal component is mainly related to the width of the notch. A variation in the height of the medial posterior condyle is observed in the third principal component. Nevertheless, it is not as significant as with the first two PCs. The study presents a statistical shape model for characterizing the fundamental modes of geometric variation in femoral bones following an ACL injury. Knowing the bony morphological features associated with ACL injuries is crucial to tailoring treatment plans to each individual.

Keywords: ACL Injury , Anatomical Variation , Morphological parameters , Principal Component Analysis , Statistical Shape Modelling

In this study, an analysis was conducted to quantify errors in the additive manufacturing process, with a focus on comparing data files. The primary objective was to minimise the reliance on physical testing of produced components by favouring verification within a virtual environment. The initial focus was on the conversion from the CAD (Computer-Aided Design) model to the STL (Standard Tessellation Language) file, where discrepancies between the two formats were identified. To achieve optimal meshing, it is crucial to configure conversion parameters effectively, avoiding both detail loss and the handling of excessively large files. Following this, a comparison between STL files and reconstructed G-code files was conducted, uncovering further approximations introduced by the most commonly used slicers. In conclusion, the analysis highlights that both the quality of the mesh and the slicing phase significantly impact the final component. Understanding these factors is essential for achieving an optimal print outcome.

Keywords: Dimension accuracy , G-code , Material extrusion , Model conversion , STL