Virtual prototyping and digital twin

Designing highly usable and ergonomic dashboards is fundamental to support users in managing and properly setting complex vehicles, like trains, airplanes, trucks and tractors. Contrarily, control dashboards are usually intrusive, full of controls and not really intuitive or usable. This paper focuses on the design of ergonomic and usable dashboard for specific classes of vehicles, like tractors and trucks. Indeed, trucks and tractors are both vehicles and operating machines, and their control is particularly complex. Indeed, the driver contemporary drives and checks if the machine is working properly. The paper proposes an innovative methodology to design highly usable and compact dashboards inspired by human-centered design and ergonomics principles. The study started by shifting the attention from the machine performance, that is the conventional engineering approach, to the human-system interaction quality, according to a new, transdisciplinary approach. The methodology proposes to combine virtual simulations with human performance analysis to support the design at different stages, from concept generation to detailed design, until testing with users. The methodology uses virtual environments to create digital twins of both driver and controls, making users interact with virtual items and predict the type and nature of interaction. Within virtual scenarios, different configurations of dashboard controls can be easily compared and tested, checking the frequency of use of each control and measuring the achieved human performance related to postural comfort and mental workload. The study adopted the proposed methodology to two industrial use cases focusing on the design of ergonomic dashboards: the former is referred to tractor dashboard and armrest, the latter refers to truck dashboard and seat. Both cases demonstrated that the new methodology allowed improved comfort, higher usability, higher visibility and accessibility, better performance and reduced time for machine control. The study demonstrates how a multidisciplinary user information integration can drive design optimization.

Keywords: Ergonomics , Human factors , Human-centered design , Usability , Virtual simulation

In this work, we propose a framework that can be used for virtual evaluation of Body-Attached Sensor Networks. Normally, the evaluation of Body-Attached Sensor Networks requires numerous subject tests under laboratory conditions. However, since it is difficult to perform the same motion repeatedly without minute deviations, numerous replicate measurements are required to obtain statistically meaningful measurements. To overcome this limitation, we propose the use of virtual environments. These provide both a high degree of flexibility, since a movement can be repeated in the same way each time, and the ability to test many different sensor setups quickly and with little effort. To this end, we modeled the human body parts of interest using the MATLAB tool Simscape Multibody. Digital twins were then implemented in this model to represent real sensors along with their sensor properties at arbitrary locations. This makes it possible to check many different sensor types and their position on the body in a short time without having to perform subject tests. This framework creates a solid basis for the development of effective Body-Attached Sensor Networks.

Keywords: Digital twins , Multibody simulation , Sensor networks , Virtual environment , Wearable

In the last decades, the flourishing of Additive Manufacturing (AM) promoted innovative design solutions in many different sectors. Despite the numerous advantages of AM technology, there are still open challenges in the field. In Fused Deposition Modelling (FDM) structures the layer-by-layer manufacturing process induces anisotropy in the material properties of the structures. The correct characterization of the mechanical properties is fundamental in the design and development stages but at the same time difficult to achieve. The experimental approach can be extremely long and expensive. An alternative is the use of an accurate numerical approach and performing a Finite Element Analysis (FEA) of the geometry which is effectively printed. However, to the best of the authors\' knowledge, there is not a common and well-established procedure to reconstruct the real geometry which is generated after the slicing process. In this paper, starting from the information provided by the G-CODE, an easy-to-use, and reproducible methodology to reconstruct the printed geometry is presented. The performance of the innovative approach is evaluated via qualitative observations by referring to several case studies. The results are thoroughly analysed, and future trends and research needs are highlighted.

Keywords: Additive Manufacturing , CAD , Fused Deposition Modelling , G-CODE

Industry 4.0 is driving the revolution of manufacturing processes by combining innovative technologies and new interaction paradigms among systems and operators. In particular, the layout, tasks and work sequences of assembly lines are designed according to several transdisciplinary Design Principles (DPs), such as process efficiency, product quality, ergonomics, safety and operators' workload. A large variety of simulation software can be employed for evaluations. However, the related ability to assess multidisciplinary factors must be evaluated. The paper aims to provide a framework for guiding the assessment of simulation software in the context of Industry 4.0 assembly lines. Process requirements are first analyzed and mapped to select DPs, prioritized according to design goals by an analytical hierarchy process. Then, suitable simulation software is determined accordingly, and the virtual model is realized. Finally, the possibility of the software to provide meaningful elaborations for the selected DPs is assessed. The framework has been tested on a prototypal Industry 4.0 assembly line composed of automated logistic systems, cobots and systems to guide the execution of tasks. The line has been modeled in Siemens Process Simulate, analyzing the completeness and appropriateness of the functionalities of this software according to the defined DPs.

Keywords: Decision Support Tools , Design Principles , Industry 4.0 , Interactive Simulation for Engineering , Transdisciplinary Engineering

Understanding user experience (UX) is essential to design engaging and attractive products, so nowadays has emerged an increasingly interest in user-centred design approach; in this perspective, digital technologies such as Virtual Reality (VR) and Mixed Reality (MR) could help designers and engineers to create a digital prototype through which the user feedback can be considered during the product design stage. This research aims at creating an interactive Digital Twin (DT) using MR to enable a tractor driving simulation and involve real users to carry out an early UX evaluation, with the scope to validate the design of the control dashboard through a transdisciplinary approach. MR combines virtual simulation with real physical hardware devices which the user can interact with and have control through both visual and tactile feedback. The result is a MR simulator that combines virtual contents and physical controls, capable of reproducing a plowing activity close to reality. The principles of UX design was applied to this research for a continuous and dynamic UX evaluation during the project development.

Keywords: Digital Engineering , Digital Twin , Human-centered Design , Mixed Reality , User experience design

Human factors integration is definitely a transdisciplinary and urgent matter in modern factories. Despite the great surge in factory automation in recent years, human-machine interaction is still a crucial aspect and companies need to take care of the workers' wellbeing and performance to enhance the overall system quality and productivity. Nevertheless, ergonomics is poorly considered during the design of complex industrial systems, such as automatic machinery, especially for the lack of practical methodologies and guidelines to promote human factors from the early stages of design or redesign. To overcome this issue, this work proposes a transdisciplinary approach to redesign automatic machinery in compliance with factory ergonomics, using a combination of digital technologies (e.g., digital human simulation, human physiological data monitoring). The paper defines a structure method and related tools to apply a human-centric approach to industrial cases and their validation of a real case, concerning the redesign of a packaging automatic machine. Results show how the proposed approach is useful to detect possible ergonomic issues at the shop floor, identifying in advance risky situations for the operators during operating or maintenance tasks, and leading to an optimized machine able to enhance the workers' wellbeing and factory productivity at the same time.

Keywords: digital human simulation , ergonomics , human factors integration , human monitoring , human-centered design

Auxetic materials can be exploited for coupling different types of tissues. Herein, we designed a material where the microorganism metabolic activity yields the formation of buckled/collapsed bubbles within gelling silicone cylinders thus providing auxetic properties. The finite element model of such hollow auxetic cylinders demonstrated the tubular structure to promote worm-like peristalsis. In this scenario, the described hybrid auxetic structures may be applied to the longitudinal intestinal lengthening and tailoring procedure to promote enteral autonomy in short bowel syndrome. The presented material and analytical design synergistic approach offer a pioneering step for the clinical translation of hybrid auxetic materials.

Keywords: auxetic materials , graphene , intestinal failure , mechanical modeling , reconstructive surgical procedures , short bowel syndrome

A full-scale test bench for the analysis of frictional and modal behavior of Nozzle Guide Vanes (NGV) is an advanced tool enabling high design accuracy for these components equipped in an increasing number of turboexpanders. This subassembly is a key feature enabling operational flexibility for the expander. Great attention must be paid during the NGV's design to the natural frequencies of its kinematic chain, which are influenced by internal clearances and by friction. In this paper the results of a testing campaign performed on an NGV assembly employing actual blade geometry are presented together with details concerning the test bench commissioning and set-up procedure. The testing campaign involves three different combinations of blade orientation and pre-load corresponding to typical design conditions of the expander. In addition, two different bushing clearances values corresponding to worn out conditions were investigated. The measurements of the global friction coefficient based on actuator force detection are summarized. After that, the reconstruction of mode shapes based on experimental modal analysis is explained. The results highlight the importance of loading conditions on the actual value of friction force and their influence on blade natural frequencies. The testing campaign was used to properly validate Finite Element Models to be used for further investigations .

Keywords: Experimental Modal Analysis , Finite Element Model Tuning , Friction coefficient , Full-scale test bench , Nozzle Guide Vanes

Remote Laser Welding (RLW) of dissimilar metallic thin foils (below 500 µm) has fundamental importance in battery pack manufacturing where high repeatability is a strict requirement. Since the welding process is very sensitive to part-to-part gaps, it is critical to understand the physical phenomena during melting, formation of the keyhole and solidification. This study has been designed to investigate the underlying physics of the welding process and understand the influence of the laser beam wobbling and part-to-part gap on temperature fields and metal mixing. A CFD multi-physics model has been implemented and then calibrated with experimental data. Two scenarios with part-to-part gap (0 and 100 µm) have been considered during lap welding of 300 µm copper to 300 µm nickel-plated steel, with circular beam wobbling. The study has highlighted that the part-to-part gap leads to uncontrolled metal mixing. Potential strategies for weld optimization are discussed throughout the paper.

Keywords: battery pack manufacturing , CFD simulation , dissimilar metals & metal mixing , laser beam wobbling , part-to-part gap , remote laser welding

The ongoing cultural heritage transition process, in which elaborate digitization plans for cultural artifacts are developed to overcome concerns about the objects' long-term preservation and storage, is now addressing issues for improving and expanding access to digital objects. As a result, new techniques and cutting-edge tools are needed for galleries, libraries, archives, and museums players to deploy and distribute the richness of knowledge housed inside cultural property. Accordingly, the present work provides an overview of the most significant studies addressing the use of innovative technologies for virtual museums and develops some thoughts on how the state of the art is improving as technology progresses. Following a discussion of the most current and significant research on this topic, the article drafts a number of proposals on how the state of the art might be overcome in the near future.

Keywords: 3D acquisition , Annotated models , Augmented reality , Virtual museums

Since every structure in the human body can vary, customization is important to choose the most appropriate medical option according to the patient. Total knee arthroplasty (TKA) is a surgical procedure for the knee replacement that has a high rate of patient's dissatisfaction. Indeed, conventional prostheses are based on anthropometric data that accommodate common knees. However, mismatch can occur due to anatomical variations among the individuals. Thanks to the advances in imaging techniques and 3D modeling, it is possible to create customized knee implants starting from medical images. In this context, the present research proposes a methodology to design a customized knee implant taking into account clinical (e.g., prosthesis alignment and surgical cuts) and technical parameters (e.g., materials) that have a direct impact on TKA performance and patient's satisfaction. Changing these parameters, different scenarios have been modeled and simulated to understand the most suitable combination. Finite element analysis (FEA) has been employed to simulate and compare the proposed customized models, changing the different clinical and technical parameters. Stress induced by different combinations of the parameters has been evaluated to choose the optimal solution among the eight proposed scenarios. The optimum is reached with a physiological alignment, with six femoral facets and the ultra-high molecular weight polyethylene (UHMWPE) tibial insert. The implant design maintains the natural joint line and allows preserving more bone. The material is the parameter that mostly influences the stress distribution.

Keywords: computer aided design , computer aided engineering , customized knee implant , femoral component optimization , finite element analysis , knowledge engineering , patient-specific knee prosthesis , total knee arthroplasty , virtual prototyping

This work presents an aerodynamic and structural optimization for a Droop Nose Leading Edge Morphing airfoil as a high lift device for the UAS-S45. The results were obtained using three optimization algorithms: coupled Particle Swarm Optimization-Pattern Search, Genetic Algorithm, and Black Widow Optimization algorithm. The lift-to-drag ratio was used as the fitness function, and the impact of the choice of optimization algorithm selection on the fitness function was evaluated. The optimization was carried out at various Mach numbers of 0.08, 0.1, and 0.15, respectively, and at the cruise and take-off flight conditions. All these optimization algorithms obtained effectively comparable lift-to-drag ratio results with differences of less than 0.03% and similar airfoil geometries and pressure distributions. In addition, an unsteady analysis of a Variable Morphing Leading Edge airfoil with a dynamic meshing scheme was carried out to study its flow behaviour at different angles of attack and the feasibility of leading-edge downward deflection as a stall control mechanism. The numerical results showed that the variable morphing leading edge reduces the flow separation areas over an airfoil and increases the stall angle of attack. Furthermore, a preliminary investigation was conducted into the design and sensitivity analysis of a morphing leading-edge structure of the UAS-S45 wing integrated with an internal actuation mechanism. The correlation and determination matrices were computed for the composite wing geometry for sensitivity analysis to obtain the parameters with the highest correlation coefficients. The parameters include the composite material qualities, thickness, ply angles, and the ply stacking sequence. These findings can be utilized to design the flexible skin optimization framework, obtain the target droop nose deflections for the morphing leading edge, and design an improved model

Keywords: algorithms , composite , correlation matrix , morphing airfoil , optimization , unsteady aerodynamics

At Annone di Brianza (Italy) in the Church of St. George, it is possible to admire the “ANCONA DELLA PASSIONE" (altarpiece of the Passion), an altarpiece painted and gilded carved wood cabinets. The great altarpiece adorned the right side chapel of Saint John the Baptist, whose construction dates back to the first half of the century XVI at the behest of Annoni, one of the most authoritative families of Milan of the sixteenth and seventeenth century. Since 2019 the altarpiece has been protected inside a special room in order to avoid damage caused by the temperature and humidity. Access to this room is not allowed to people who visited the church. In order to allow the user to admire and explore each minimal detail of the polyptych altarpiece a totem has been designed and it's located just outside of the special room. The totem in fact is composed of a 32 in. touch screen with a PC embedded and the Virtual tour application. The Virtual tour application has been developed with Unity3D. The interactive application has different virtual scenes with photos, videos, an external digital twin of the polyptych with both, open and closed doors.

Keywords: Digital twin , Inclusive tour , Photogrammetry , Virtual tour , Visual impairment users

Complex manufacturing systems are recently undergoing a green revolution due to manufacturing customization towards sustainable products. A key enabler for the implementation of green and energy efficient production is simulation-based design, which supports system engineers and designers in making decision choices aimed at enhancing the performance of smart and sustainable production. In this context, this work proposes a simulation approach to support the design of the layout and operation of automated guided vehicles (AGVs) in complex production lines. In particular, a case study related to the assembly of electric axles for heavy-duty vehicles is presented: a scenario analysis implemented in the Plant Simulation platform is used to determine the optimal configuration of AGVs in terms of number of vehicles and operation (e.g., definition of charging strategies, scheduling of charging stops, routing). The simulation results first show that the reduction of the AGVs' energy consumption and the increase of production throughput are competing criteria; second, the choice of AGV charging strategies has a significant influence on the energy consumption as well as on the productivity performance.

Keywords: automated guided vehicle (AGV) , Complex manufacturing systems , discrete event simulation , sustainable and efficient manufacturing , what-if analysis

The recent increase on the Internet of Things and Industry 4.0 fields has led the research topics to investigate on the innovative technologies that could support these emerging topics in different area of applications. In particular, the current trends are to close the gap between the physical and digital worlds, thus originating the so-called Cyber-Physical System (CPS). A relevant feature of the CPS is the digital twin, i.e., a digital replica of a process/product with which user can interact to operate on the real world. In this paper, the authors propose an innovative approach exploiting an Augmented Reality solution as Digital Twin for the measurement instrument to obtain a tight connection between the measurements as physical world and the Internet of Things as digital applications. In fact, by means of the adoption of the 3D scanning strategy, Augmented Reality software and with the development of a suitable connection between the instrument and the digital world, a Cyber-Physical System has been realized as an IoT platform that collect and control the real measurement instrument and makes its available in Augmented Reality. An application example involving a digital storage oscilloscope is finally presented to highlight the efficacy of the proposed approach.

Keywords: augmented reality , Cyber-physical systems , digital twin , measurement instrumentation , remote control

High Strength Steels (HSS) are widely used in the automotive industry to reduce the vehicle's weight and improve fuel efficiency. The press hardening process is used, for instance, to form and harden low-alloyed steel simultaneously. A deep understanding of the interfacial phenomena and the friction behavior at high temperatures is significant in describing the process, especially when considering Finite Elements (FE) analysis. In this paper, the results of a series of tensile friction tests carried out with aluminum-silicon coated low alloyed steel 22MnB5 for different values of drawing speed, temperature, and die pressure are investigated. All tests were conducted by a special test rig designed by the authors. Following the Surface Response Methodology approach, a Central Composite Design was used to identify the best fitting friction model that approximates the friction coefficient behavior depending on the main testing parameters. The identified model can explain up to 88% of the variability of the response variable and predict the friction coefficient with acceptable error. In conclusion, a FE multi-physical model of the tensile friction test, which combines a structural and a thermal analysis, was created and validated by LS Dyna software simulations.

Keywords: central composite design , friction , high strength steels , press hardening , response surface methodology , tensile friction test

One of the major barriers to close the gaps between the academic paradigm of Product Lifecycle Management (PLM) and the actual potentialities offered by modern PLM implementations in industry is represented by the inherent difficulty in the management of product information structured over a formalized product-related knowledge. This is especially true for complex, highly customized and engineer-to-order products. The amount, the complexity and the variability of the information throughout the lifecycle makes the Product Data Management capabilities inadequate to realize the required level of accessibility. Ontologies and Semantic Web Technologies are a promising solution in addressing the aforementioned challenges relevant to PLM. Despite that, ontologies implementations in real industrial applications remain very limited in number and, in any case, either are restricted to specific areas or tackle the issue from a too general point of view. The paper aims to present a generalized approach to structure a product knowledge domain over a general-purpose, agnostic “base” ontology. It has been developed on top of formal model taken from literature, where the knowledge relative to a complex, highly customized and engineer-to-order (ETO) product from Oil & Gas Turbomachinery industry was formalized in an OWL-DL ontology enriched with SWRL rules and reasoning capabilities. To facilitates the interaction and the validation with the formal model, a Graphical User Interface (GUI) has been implemented. It enables the penetration of reasoning-enabled ontologies within industrial mindsets and forms the foundations for future integration of the generated product information layer within industrial PLM ecosystems. Within this context, IT asset used to realize the presented proof-of-concept is described and major challenges encountered during the realization and the way they have been tackled are discussed, together with strengths and limitations associated to the approach.

Keywords: Graphical user interfaces , Information management , Knowledge based systems , Life cycle

Metal Additive Manufacturing technologies provide many advantages among industrial sectors. Most applications exploit design freedom for functional design enabled by Powder Bed Fusion processes, while Directed Energy Deposition systems are mainly restricted to the construction of large parts and reparation of damaged components. Nevertheless, the latter provide not only high deposition rates, but also high flexibility, and the possibility to process multi-materials, to grade and combine their characteristics for enhanced features and performance. Therefore, a rising application is the remanufacturing of existing components to produce functional design variants. Those parts can integrate different features and materials through direct deposition of metals over bounded areas. This work concerns the development of a Design for Additive Remanufacturing methodology for existing components with improved performances to be produced by the laser-based Direct Metal Deposition process. It relies on the use of CAD platforms for the integrated design of products and the associated processes. The design approach is based on the integration of CAE structural analysis and Topology Optimization, to define the location and the morphology of deposited structures. The design of an automotive suspension arm with enhanced performances is the use case to demonstrate the effectiveness of the approach, which could be extended to the remanufacturing of several bodies and chassis automotive subsystems.

Keywords: Design for Additive Manufacturing , Finite Element Analysis , Hybrid Manufacturing , Laser Metal Deposition , Remanufacturing , Topology Optimization

This research concerns the optimization study of the wing of an ultralight competition sailplane, category F5J/F3J. Fundamental for this category is the characteristic of lightness associated with good wing stiffness (bending/torsional). All the elements composing the wing of the sailplane were modelled in 3D by using the Autodesk Inventor parametric solid modeler. They were assembled in the FEM environment and were suitably constrained and studied from a structural point of view. The structural characteristics of the wing and its components were analysed in detail after assigning the materials currently used and adopting appropriate materials to make the same with the Additive Manufacturing (AM) technic. A topological optimization, performed by using the Simplex Method (SIMP), was conducted on the internal structure of the wing in order to lighten the ribs with the same performance. The experimental investigations implemented in the laboratory allowed the 'Oralight' material used for the wing surface coating to be characterized. It is an extremely thin and light material, whose elasticity and strength were accurately assessed in this study. The data obtained, considered along with the elasticity and the resistance values of the other materials constituting the wing structure, taken from the literature, were inserted into the finite element simulations with the aim of evaluating the torsional and bending stiffness of the wing. Finally, the rib was redesigned using a FDM material which makes construction particularly simple.

Keywords: Oralight Coating Surface , Compound Bio-Plastic Filament , Ribs and Spars' Redesign , Torsional and Bending Wing Stiffness , Wing Parametric Modelling

According to standards, a fundamental gear design parameter, which heavily influences the sizing of these mechanical components, is the gear tooth root bending strength. To establish this parameter in a reliable way, tests should be performed on running gears (RG) manufactured with the same material and heat treatments under investigation. However, it is common practice in industry and in academia to perform single tooth bending fatigue (STBF) tests, which, on the one hand, are simpler and cheaper to perform, on the other hand, the stress history (t ) they induce is not identical to that obtained during RG meshing. Therefore, it is necessary to apply a correction coefficient (fkorr) to translate data obtained via STBF in RG design data. In recent studies, a method to estimate fkorr through the combination of finite element (FE) simulations and the implementation of multiaxial fatigue criteria (MFC) based on the critical plane concept has been proposed. This method consists of simulating through FE a gear geometry both in the RG load case and in the equivalent STBF condition. Through the load histories recorded on the nodes belonging to the critical area, it is possible, by implementing different MFC, to identify the most critical node and the relative Damage Parameter (DP). The ratio between the obtained critical DP of the STBF case and RG provides the value of fkorr. However, different MFC can lead to different results in terms of fkorr. This is because different MFC differs in the definition of the DP. More specifically, DPs are both functions of material properties, such as the fatigue limit of the material related to symmetric sinusoidal bending stresses (σf) and the fatigue limit at sinusoidal cyclic torsional stresses (τf), and load-dependent characteristics. The goal of this paper is to investigate the effect of different material properties, i.e. σf and τf , on the estimation of fkorr highlighting differences between the various MFC implemented, i.e. Findley, Matake, Papadopoulos, and Susmel et al. To this respect, the above-mentioned numerical method has been applied to a specific gear geometry whose material properties have been systematically varied. Results show that the criteria of Findley and Papadopoulus lead to very similar results and a monotonically increasing relationship between fkorr and τf /σf . A similar trend is observed for the Susmel et al. criterion but with higher value of fkorr Differently, the criterion of Matake leads to a monotonic decreasing relationship between fkorr and τf /σf

Keywords: Critical plane , FEM , gears , material characterization , multiaxial fatigue , STBF