bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards Multi-Scale Modeling of Zirconium Alloys Recrystallization and Application to Thermo-Mechanical Processes Optimization
Authors: Gaillac Alexis , Grand Victor , Arsen Alan , Gaillard Quentin , Bernacki Marc
Published: July 2022

Zirconium alloys are used in the nuclear industry due to their low neutron capture cross-section and resistance to corrosion, irradiation and creep. The microstructure of the nuclear fuel components evolves during the manufacturing route and can impact the subsequent processes or the final properties. Thus, numerical modeling of thermo-mechanical manufacturing processes is of interest to understand and master these microstructure evolutions.Numerical modeling of thermo-mechanical manufacturing processes with FORGE® NxT software is applied. These models provide the thermo-mechanical history of the material at each integration point of the finite element (FE) mesh, which can be used to assess locally the continuous dynamic and post-dynamic recrystallization during hot extrusion.Mean-field models were developed in Python and integrated into FORGE® NxT software, to quantify the microstructure evolution at the macro-scale of the component. Full-field models (DIGIMU® software1) were also developed for considering microstructural heterogeneities and the influence of initial microstructure at the mesoscopic scale while improving the mean-field equations by homogenization.After validation based on experimental results, these two recrystallization models provide complementary information to optimize the process parameters at the macro-scale and to better understand mesoscopic scale phenomena, such as:• At the macro-scale: influence of hot extrusion parameters on the continuous dynamic and post-dynamic recrystallization of Zircaloy-4.• At the meso-scale: influence of the initial microstructure on the recrystallization phenomena with improved precision. Indeed, the topology of the microstructure is predicted and not only the mean values/distributions of the state variables.
In-Mold-Assembly of Hybrid Bending Structures by Compression Molding
Authors: Stallmeister Tim , Tröster Thomas
Published: July 2022

The further development of in-mold-assembly (IMA) technologies for structural hybrid components is of great importance for increasing the economic efficiency and thus the application potential. This paper presents an innovative IMA process concept for the manufacturing of bending loaded hybrid components consisting of two outer metal belts and an inner core structure made of glass mat reinforced thermoplastic (GMT). In this process, the core structure, which is provided with stiffening ribs and functional elements, is formed and joined to two metal belts in one single step. For experimental validation of the concept, the development of a prototypic molding tool and the manufacturing of hybrid beams including process parameters are described. Three-point bending tests and optical measurement technologies are used to characterize the failure behavior and mechanical properties of the produced hybrid beams. It was found that the innovative IMA process enables the manufacturing of hybrid components with high energy absorption and low weight in one step. The mass-specific energy absorption is increased by 693 % compared to pure GMT beams.
On the Identification of Material Constitutive Model Parameters Using Machine Learning Algorithms
Authors: Marques Armando , Pereira André , Ribeiro Bernardete , Prates Pedro André
Published: July 2022

This work aims to evaluate the predictive performance of various Machine Learning algorithms when applied to the prediction of material constitutive parameters, particularly the parameters of the Swift hardening law. For this, datasets were generated from the results of the numerical simulations of uniaxial tensile tests. The Machine Learning algorithms considered for this study are: Gaussian Process, Multi-layer Perceptron, Support Vector Regression, Decision Tree and Random Forest. These algorithms were used to train metamodels based on training sets considering different numbers of materials and input parameters, which were then used to predict the hardening law parameters. The Gaussian Process algorithm achieved the overall best predictive performances. The results obtained show the potential of Machine Learning algorithms for application on the identification of material constitutive parameters.
Mechanical Behaviour of Magnesium Alloy Based - Fiber Metal Laminates after Fabrication Using Different Metal Surface Treatments
Authors: Liu Zheng , Simonetto Enrico , Ghiotti Andrea , Bruschi Stefania
Published: July 2022

This paper presents an experimental investigation of the mechanical response and failure mode of magnesium alloy-based Fibre Metal Laminates (FMLs) having different surface pretreatments under axial compression loading conditions. To improve the interfacial bonding strength between the metal and composite layers, three categories of samples were fabricated by hot pressing using sandblasted, annealed and both sandblasted and annealed AZ31B magnesium alloy sheets. To evaluate the bonding strength along the shear and normal directions, single lap shear tests and T-peel tests were conducted. It was found that the combination of sandblasting and annealing can greatly enhance the shear and normal interfacial bonding strength compared with only sandblasting and annealing, separately. To assess the effect of the interfacial bonding strength on the FML compressive performance, quasi-static buckling tests were performed at varying surface treatments of the magnesium alloy sheets. The analysis of the load-stroke curves and failure modes indicates that delamination can significantly reduce the buckling capability and structural stability, and that the improvement of interfacial bonding strength can dramatically strengthen the FML compressive capability.
Surface Quality and Mechanical Properties in Drawn Stainless Steel Profile Wires Caused by Process Parameters
Authors: Kwiecień Marcin , Majta Janusz , Rumiński Maciej , Kawałko Jakub , Muszka Krzysztof
Published: July 2022

Thin profile wires made of stainless steels are widely used for production of industrial screens used for filtration and separation processes. Industrial screens made of resistance spot welded thin profile wires are used e.g. in baskets for centrifuges or filtration screens and find a wide range of applications in various branches of the industry (mining, food and sugar industry, paper industry, wastewater treatment, oil and gas and many more). Regardless of the application, increased durability and surface quality of the screens is of paramount importance. Improvement of the longevity of manufactured items, process efficiency and environmental performance can be achieved only when interactions between initial wire rod quality and its susceptibility to metal forming operations are fully understood. Due to the complexity of the manufacturing process of industrial screens (precise and small gaps, narrow ranges of dimensional tolerances), forming of thin, so-called precision profiled wire is difficult. The influence of the charge, i.e. wire rod, parameters of the wire drawing / rolling process play a key role in obtaining semi-finished products characterized by high strength, low surface roughness and a low level of residual stresses. The paper discusses the influence of the initial state of wire rod and deformation parameters on the quality of thin austenitic and lean duplex steel profile wires as well as the possibility of replacing austenitic wires by lean duplex wires and their possible benefits.
Cold Sprayed Metallic Coatings on Fibre-Reinforced Composites: A Machine Learning Approach for the Optimization of the Process
Authors: Perna Alessia Serena , Carrino Luigi , Della Gatta Roberta , Viscusi Antonio
Published: July 2022

Cold spray additive manufacturing (CSAM) is a promising process for producing metallic layers on different substrates, using powders as a feedstock material. The metallic powders are deposited through pressured gas that reaches supersonic velocities. Due to the low heat input required, as the powders remain in solid-state, this technology is particularly suitable to coat thermo-sensitive materials such as composites. Moreover, the absence of melting allows design freedom, allowing to build complex structures on the substrates, layer by layer. In this scenario, machine learning techniques can be crucial to improve the quality and understanding of this manufacturing process. The aim of this work is to predict the deformation and penetration of a particle upon impact using machine learning techniques in order to assess the properties of the coating. A univariate linear regression method was chosen to verify the feasibility of Theory Guided Machine Learning (TGML) techniques to predict the characteristics of the coating. The training dataset was obtained from both experimental data and computational data. It was confirmed that TGML could be a good route to pursue in order to optimize this process.
Effects of Tool-Workpiece Friction Condition on Energy Consumption during Piercing Phase of Seamless Tube Production
Authors: Aghajani Derazkola Hamed , Garcia Eduardo , Murillo-Marrodán Alberto
Published: July 2022

During the hot piercing phase of seamless tube production, friction and contact conditions between tools and workpiece significantly influence final product quality and energy consumption. The friction effects on the production of high alloyed steels like Super Cr13 steel are critical. This study analyses the effect of different friction conditions at the workpiece-tool interface in the piercing of Super Cr13 steel bars to minimize total energy consumption in such a manufacturing process. For this purpose, a three-dimensional finite element method (FEM) is employed to simulate and analyze the piercing process. The variety of tools (plunge, rollers, and Diescher disks) and contact conditions lead to differences in the applied stress at different workpiece areas. Consequently, various friction models and friction coefficients were selected for different interfaces. The relation between strain rate, temperature, and geometry of pierced tube are discussed, and the selected friction relation with total power and energy consumption is presented. Experimental tests have been used for FEM validation and result analysis, and finally, the most effective conditions with lower total energy consumption are presented.
Modelling Thermoplastic Filaments’ Sintering by Level Set Method
Authors: Chaunier Laurent , Belhabib Sofiane , Guessasma Sofiane , Reguerre Anne-Laure , Leroy Eric
Published: July 2022

The viscous sintering kinetics of thermoplastic polymers is generally studied by monitoring the evolution of the bonding neck between two particles (spherical, or cylindrical) and using a refined Frenkel-Eshelby’s model. Recently, we showed that the entire contour of sintering filaments could be modelled by lemniscates as figure-eight shape curves to assess bonding abilities of a 3D-printable plasticized biopolymer. Using COMSOL Multiphysics® software, we set up a 2D finite element model of thermoplastic filaments’ viscous sintering with flow front tracking by the level set method. This leads to contrasted images of the two phases, i.e. air and polymer, allowing the prediction of the shape of the interface corresponding to the filaments’ contour. An image analysis procedure is applied to the simulated sequences and the ones acquired during sintering trials of extruded filaments based on zein, a corn protein plasticized by 20w% glycerol. This method is based on the assessment of the coordinates of sintered filaments’ edge pixels and their fitting by lemniscates of Booth. We show that the 2D FEM approach combined with level set method allows simulating the hot melt viscous sintering of a 3D-printable thermoplastic biopolymer as a two-phase flow. Furthermore, the image analysis is successfully applied to simulated and experimental sequences, thanks to the monitoring of the filaments’ contour, to assess their bonding kinetics and check its modelling.
Fine Blanking Limits of Manganese-Boron-Steel in Fine Blanking Compared to Tempered Steel with Variation of Sheet Metal Temperature
Authors: Weiser Ingo Felix , Herrig Tim , Bergs Thomas
Published: July 2022

Fine blanking is a key technology for the near-net-shape production of sheet metal components. It is often used in combination with processes such as deep drawing. With increasing environmental requirements, the processing of materials with lightweight construction potential is becoming more and more important. A group of materials with high potential for lightweight construction, not only due to their suitability for hot stamping, is the group of manganese-boron steels. The fine blanking properties of these steels have not yet been exhaustively investigated. In this work, the fine blanking properties of the manganese-boron steel 40MnB4 were investigated in comparison to the quenched and tempered steel 42CrMo4. This was done using a star-piece fine blanking layout with investigation of die roll as well as tooth tip cracking. Furthermore, an investigation of the high-temperature fine blanking properties were investigated by means of inductive heating prior to fine blanking. The process forces were evaluated depending on the sheet metal temperature. A good fine blanking capability of 40MnB4 could be confirmed. Process forces and product quality were comparable to 42CrMo4 steel. Accordingly, an industrial application of fine blanking to manganese-boron steels seems highly promising.
Characterization of Surface and Bulk Features of SLM Parts
Authors: Bruni Carlo , Ciccarelli Daniele , Mancia Tommaso , Pieralisi Massimiliano , Greco Luciano
Published: July 2022

An experiment-analytical procedure based on the building of an object in severe atmosphere resistant steel by SLM is proposed. The complex shape was investigated with the sectioning and laboratory observation of the physical object. The study evidenced the need to get a variable layer thickness to follow double curvature complex shapes. In particular the key variable in the process is the melt bath dimension by which the metal powder assumes by solidification the required global geometry. It was observed that the bath detected mainly in terms of the area in the section tends to decrease when approaching the surface of the physical model where the complex geometry needs to be described. Relationships describing the bath area behaviour and correlations between surface roughness and internal bath dimensions were found and proposed in detail. The surface roughness is highly correlated with the bath area in the zones of the section approaching the surface.
Influence of Geometric Parameters on Buckling Behavior of 3D Printed Anisogrid Structures
Authors: Gentili Serena , Greco Luciano , Mancia Tommaso , Simoncini Michela
Published: July 2022

The present work aims at studying the buckling behavior of lattice structures realized by additive manufacturing technology. To this purpose, carbon fiber reinforced thermoplastic filaments have been used to realize anisogrid structure at different geometric parameters by means of Fused Filament Fabrication technology. Eight configurations were realized varying the rib width and the rib thickness of the structures, and keeping constant the cell height value. Anisogrid structures were tested under compressive load in order to investigate the effect of geometric parameters on strength and specific strength exhibited by the structures. It has been shown that mechanical performances of lattice structures are highly affected by the geometric parameters of the anisogrids.
Capillary Driven Saturation of Textile Reinforcing Structures Proposal for an Extension of Lucas-Washburn Equation
Authors: Schledjewski Ralf , Blößl Yannick , Neunkirchen Stefan
Published: July 2022

Liquid composite molding (LCM) is a widely used group of various different processing techniques allowing to produce small, medium or even very big sized components from prototype level up to series production. During the infiltration it is necessary to run the process in a way preventing void formation. The typically used textile reinforcing structure results in a dual-scale impregnation consisting of micro impregnation within the constituent yarns of the textile structure and a macro impregnation between the yarns. Capillary rise experiments on flat textile samples are used and the well-known Lucas-Washburn equation has been extended to cover the special configuration. A porous capillary wall is assumed to better represent the three-dimensional nature of capillary networks within reinforcing textiles. An according test rig is presented. Accurate experimental results are gained and capillary radii are computed simple and fast via curve regression.
Drillability of Magnesium-Based Fiber Metal Laminates Obtained via Hot Metal Pressing with Different Metal Surface Treatments
Authors: Lizzul Lucia , Bertolini Rachele , Sorgato Marco , Ghiotti Andrea , Bruschi Stefania
Published: July 2022

The demand for lighter and more performant aerospace and automotive components has resulted in a substantial surge in a recent interest in parts made of Fiber Metal Laminates (FMLs). For such components, drilling operations are crucial for permitting subsequent assembly. However, drillability of fiber metal laminates is critical due to the heterogeneous thermal and mechanical properties of the metal and composite that form the laminate. In this framework, the current research work aims at understanding how drilling operations can be affected by different surface treatments carried out on AZ31B magnesium alloy sheets joined with Glass Fiber Reinforced Polyamide 6 (PA6-GFRP) via hot metal pressing to form the FML. To this end, the Mg/PA6-GFRP/Mg composites were first fabricated using AZ31B surfaces that were previously treated through sandblasting, annealing, and their combination. Dry drilling was then performed using twist and spur drill bits. The feed was also varied, using two levels. The thrust force, hole quality, delamination and fiber pull-out were considered to evaluate the FMLs drillability. Results showed that the magnesium alloy sheet treatment influenced the drillability, and that the drill bit had an effect too. In particular, sheets that were both sandblasted and annealed allowed the highest drillability avoiding delamination. The use of spur drill bits improved the drillability too, reducing the FML inflection under the drill bit load.
Improvement of Package Properties with Formed Functional Surface Features
Authors: Leminen Ville , Tanninen Panu , Pesonen Antti , Matthews Sami
Published: July 2022

Paperboard package properties can be improved by embossing functional features on package surfaces. Embossing is used in package manufacturing as an additional tool to improve the appearance of the packages. It can also be used to increase product safety by improving functionality and identifiability of packages. Creation of features directly on the base material without implementing additional components improves the sustainability level of package applications. To evaluate functionality of features, such as protective surface patterns, in the applicable practice, the following steps need to be gone through; design phase, tool manufacturing phase, pattern production phase and analysis phase. Bespoken toolsets were designed and manufactured to form a protective frame around commercial radio-frequency identification tag (RFID). The essential process parameters in the embossing experiments were the pressing force and the plate temperature which were optimized in preliminary tests. Methods for evaluating the performance of created embossed patterns were wear testing of package surfaces, topography measurement with a 3D profilometer and SEM-imaging for more detailed analysis. The results show that embossing is a suitable manufacturing method for creating targeted functional features on paperboard surfaces. With the formed surface features, the functionality of the packages was improved by protecting the identification labels.
Defects Reduction in the Robotic Layup Process
Authors: Gambardella Antonio , Esperto Vitantonio , Tucci Fausto , Carlone Pierpaolo
Published: July 2022

Robotic layup is a novel process developed to face the increasing demand for automation, flexibility, repeatability, and achieving high-quality composite materials in relevant industry fields, such as aerospace and automotive. This process is based on laying prepreg tissues on a mold using the action of a robotic arm equipped with a specific end-effector, which is usually composed of rollers and punches. The main drawback of the robotic layup is the occurrence of wrinkles and defects while moving, placing, and processing the pre-impregnated tissues. This issue is particularly evident in the processing of complex-shaped surfaces. The robotic arm cannot replicate exactly the movement of a human operator, following the geometry of the surfaces with a proper angulation like a human wrist. Moreover, operator hands can be set in a different shape just changing the configuration of the fingers, adapting themself in different curvatures. The demand of the industry to improve automation requires that the robotic manufacturing systems replicate as much as possible the gesture of the operator. In this study, an end-effector capable to replicate the human movements during the hand layup of fibrous tissues or fabrics has been conceptualized.
Elaboration of Parameters of Large-Size Rings Production Process Taking into Account the Evolution of Material Relative Density
Authors: Lisiecki Łukasz , Łukaszek-Sołek Aneta , Majta Janusz , Kajpust Szczepan , Misiowiec Sławomir , Muszka Krzysztof
Published: July 2022

The paper presents the selected problems in production chain of large-size rings for the offshore industry. There are two goals of the technology: 1) to obtain the correct shape of the rings, 2) to achieve required properties. A significant problem in the processes of large size forgings production is a proper prediction of the as-cast structure defects and their behaviour during deformation (forging). This study examines a method of prediction of relative density changes of the material during forging. Experimental procedure includes a forging test at the laboratory scale and numerical modelling. These results as well as boundary conditions were used as input data for the computer simulations of the large rings production processes. The presented procedure allows for a comprehensive analysis of the production process of large-size rings, taking into account areas with insufficient material compaction. The analysis allows for changes in the production chain at the design stage, which significantly reduces the costs associated with pre-implementation tests.
Large Scale Forming of Non-Crimp Fabrics for Aerostructures
Authors: Jimenez Martin Claudia , Maes Vincent , McMahon Turlough , Kratz James
Published: July 2022

The increased production rate targets of the aerospace industry have driven the development of dry fibre infusion processes. Biaxial Non-Crimp Fabrics (NCFs) are considered in this work due to their potential high deposition rates and higher mechanical performance to woven fabrics. Forming is an integral step prior to infusion and curing. Understanding the forming behaviour of NCFs at scale is therefore key to achieving high quality parts at high rates. To investigate the draping and shearing behaviour of NCFs, geometries with complexities associated with the composite structure are used. This study presents an experimental campaign on two large scale (2 metres in span) geometries with complexities seen in primary aerostructures. The combination of features such as ramps and curvature with corner radii leads to distinctive out-of-plane wrinkling. The relationship between geometry, material and resulting preform quality is observed through the use of 3D scans. Results show differing preform quality in terms of wrinkling phenomena, showing the importance of geometry of choice for material drapability tests at an industrial scale.
18Ni300 Maraging Steel Produced via Direct Energy Deposition on H13 Tool Steel and DIN CK45
Authors: Gil Jorge , Seca Ricardo , Amaral Rui , Emadinia Omid , Reis Ana , de Jesus Abílio
Published: July 2022

The quality of metallic additive manufacturing outputs is heavily dependent on the employed processing parameters. Hence, the assessment and definition of the input variables appropriate to the material in question is of vital importance, in order to optimise the attainable properties and minimise wasted feed stock in failed trials. In this work, optimal parameters for 18Ni300 Maraging steel are found for deposition in an H13 substrate. Additinally, the influence of pre-heating in depositions on a DIN CK45 steel are analysed by optical microscopy (OM) and microhardness measurements along the interface, and mechanical characterisation of DED-produced 18Ni300 is performed, as well as a bi-metallic alloy comprised of 18Ni300 and CK45, through the production and testing of tensile specimens.
An Approach for an Innovative 3D Steel Strip Straightening Machine for Curvature and Saber Compensation
Authors: Bader Fabian , Bathelt Lukas , Djakow Eugen , Henke Christian , Homberg Werner , Trächtler Ansgar
Published: July 2022

Due to increasing globalization and rising quality requirements, the steel and metal processing industry is facing growing cost and innovation pressure. Not least because of their high lightweight potential, high-strength steel materials are meeting the growing material requirements of steel and metal processing in areas such as aerospace and medical technology. In particular, the tight tolerance limits of applicable shape and dimensional accuracies pose a challenge in the processing of high-strength steel strip materials. Improving the processability of high-strength steel materials through the use of straighteners with set-up assistance systems significantly increases the potential for competing with other materials such as aluminum or magnesium alloys.
Recycling of Powders from Cutting of Medium Density Fiberboard
Authors: Quadrini Fabrizio , Bellisario Denise , Iorio Leandro , Proietti Alice , Regi Marco , Loredana Santo
Published: July 2022

Medium density fiberboard (MDF) is a wood-based engineered material, largely implemented in the manufacturing of in-house structures. Large panels are usually manufactured and shaped via machining; in this way powders are produced. Dismissed structures can also be pulverized to facilitate transportation of waste. MDF is generally dismissed through landfill or incineration. The aim of this work is to determine a recycling method for MDF powders that make it possible to obtain ready-to-use panels without using virgin or additional materials. Powders granulometry is evaluated and then grains are “direct molded” by a parallel plate hot press. Compression molding was used for this aim. Recycled panels had the size of 200x200 mm2, a thickness of 5 mm, and a smooth surface without evident defects. Burrs were absent. Mechanical properties were evaluated under bending test, and a maximum strength over 8 MPa was found. Results show the feasibility of this recycling technology for MDF powders. Agglomeration occurred thanks to the powder re-activation, and possible residual reactivity.
Mechanical Behavior of Innovative Reinforced Aluminum Foam Panels
Authors: Durante Massimo , Boccarusso Luca , Carrino Luigi , Formisano Antonio , Viscusi Antonio
Published: July 2022

Metals foams are attracting great interest in aerospace, automotive and military fields. Particularly, the closed-cells aluminum foams are characterized by peculiar properties, such as low specific weight coupled with high energy absorption capacity, high specific stiffness and strength and reduced thermal and electrical conductivity. For the above reasons, aluminum foams can be effectively used as core of sandwich structures, replacing the traditional honeycomb and polymer-based foams. However, under specific loading conditions, the foam core was proved to collapse because of the bubble-cell structure, so affecting the mechanical performance of the sandwich constructions. Different solutions have been studying in literature to reinforce the foam-based core; for example, the authors in previous studies investigated the possibility to use a metal grid inside the core as a corrugated skeleton, to improve its behavior under compression. Therefore, based on these premises, the aim of this work is to improve understanding of the mechanical behavior of innovative reinforced aluminum foam panels through an experimental approach consisting of three-point bending tests. In particular sandwich structures with and without a corrugated grid structure, acting as skeleton inside the core, were manufactured. The bending properties were estimated also considering two different types of steel grid employed for the corrugated structure and for reinforcing the skins.
Non-Uniform Effect of the Contact Conditions on the Earing Profile in Cylindrical Cups of Anisotropic Materials
Authors: Neto Diogo M. , Oliveira Marta C. , Dick Robert E. , Alves José Luis , Menezes Luis Filipe
Published: July 2022

The earing profile of cylindrical cups is mainly dictated by the in-plane anisotropic behavior of the metal sheet. Nevertheless, for materials with a strong anisotropic behavior the contact conditions between the blank and the blank-holder can also affect the material flow due to the non-uniform distribution of the contact forces. The main objective of this study is to numerically assess the influence of the friction conditions on the cup earing profile using the AA3104 aluminum alloy. The strong anisotropy of the r-values of this material leads to a non-uniform thickness distribution along the circumferential direction of the flange, resulting in increased thickening in the transverse direction. The effect of the friction coefficient on the earing profile is approximately 4 times larger in the transverse direction than in the rolling direction.
Numerical Investigation of Influence of Spot Geometry in Laser Peen Forming of Thin-Walled Ti-6Al-4V Specimens
Authors: Pöltl Dominik , Keller Sören , Chupakhin Sergey , Sala Siva Teja , Kashaev Nikolai , Klusemann Benjamin
Published: July 2022

The aviation industry demands thin-walled structures of high dimensional accuracy. Varying radii and individual use-cases, e.g. for repair purpose, require flexible forming techniques. Laser peen forming (LPF) represents such a forming process providing precise energy input by a pulsed laser over a wide energy range. Among adjustable parameters such as laser intensity and focus size, the spot shape, i.e. square and circular, is usually fixed for a specific laser system. As the spot shape is a crucial parameter, this work focuses on the effect of the spot shape on structural deformation after LPF application. Therefore, models for laser peen forming of thin-walled Ti-6Al-4V strips for LPF systems with circular and square focus shapes are set up. Geometric conditions on both focus shapes ensure equal energy input during the laser processing. The numerical simulation relies on the so called eigenstrain method, leading to a cost-efficient calculation of resulting deformation after the dynamic LPF process. Square-based peening pattern exhibit higher deflection. For increasing spot size, the deflection difference between square and circle-based patterns increase slightly.
Data-Based and Analytical Models for Strength Prediction of Mechanical Joints
Authors: Vancraeynest Niels , Jäckel Mathias , Coppieters Sam , Drossel Welf Guntram
Published: July 2022

Currently the design of mechanical joining processes like self-pierce riveting with semi-tubular rivet (SPR-ST) and clinching for production is subject to complex and experimental test series in which process parameters such as the rivet or die geometry are varied iteratively and based on experience until a suitable joint contour and strength is achieved. To simplify the use of mechanical joining technologies these development cycles and thereby the effort for implementation into production must be reduced. In this paper, the numerical data-acquisition and the development of algorithm-based and analytical models for strength prediction for SPR-ST and Clinching is described. Therefore, an extensive experimental and numerical database regarding the SPR-ST process and strength of steel and aluminum joints with tensile strengths of the sheets between 200 - 1000 MPa was generated for the building of the models. This process data could then be used for the training and evaluation of different prediction models. The goal of the research presented here is to enable an immediate prediction of the quasi-static joint strength, based on the input parameters such as properties of the parts to be joined and process parameters.
Local Formability of Different Advanced High Strength Steels
Authors: Shen Fu Hui , Wang He Song , Xu Hao , Liu Wen Qi , Münstermann Sebastian , Lian Jun He
Published: July 2022

Medium-Mn steel (MMnS) is a promising candidate of the third generation of advanced high strength steels (AHSS), which can provide superior tensile properties. To consider the edge crack issues, the local formability, as an indicator of fracture resistance, of the MMnS needs to be quantitatively evaluated for their potential application to industries. Thus, the local formability of two different MMnS is evaluated by the forming limits at fracture using the damage mechanics approaches and compared with a DP1000 steel in this study. Despite the superior tensile properties, the local formability of the investigated MMnS is worse than the DP1000, which is characterized by the fracture strain under different stress states. Therefore, for the assessment of their potential application in automotive industries, it is recommended that more attention should be paid to the local formability and fracture resistance of these advanced high strength steels.
E-Textiles for Sports: A Systematic Review
Authors: Vieira Daniel , Carvalho Helder , Providência Bernado
Published: July 2022

This work presents a systematic review to provide an overview of the possibilities for coupling, fabrication or embedding of electronics into textiles whilst assuring the capability of these products to meet the requirements of a sports modality. The development of smart wearables systems for sports based on textiles attracts more and more users – motivated by design, by technology, as well as by the expectation of increased performance. A bibliographic search was carried out using the following databases: Scopus, Web of Science, IEEE Xplore and Science Direct. This study includes 32 articles and discusses these in a new taxonomy with three dimensions: measured variable, types of feedback and applications. Of the 23 technologies surveyed, this review showed that these wearable systems are mainly used for vital signs monitoring and to provide feedback on the electrical activity of the heart, with sensors mostly placed in the chest. Usually, the technologies are externally attachable rather than embedded in the textile. We observed that the implementation of design as the process of development of e-textile products is still only scarcely present in these studies.
On the Effect of Release Agent and Heating Time on Tool-Ply Friction of Thermoplastic Composite in Melt
Authors: Pierik E. Rens , Liddiard Joseph Lewis George , Grouve Wouter Johannes Bernardus , Wijskamp Sebastiaan , Akkerman Remko
Published: July 2022

Process simulation software for hot press forming requires accurate material characterizations. One of these characterizations is tool-ply friction, for which the methodology is well established. However, the experimental conditions are often not representative for the actual forming process. This research focuses on the effect of release agent and heating time on the tool-ply friction response. UD carbon fiber-reinforced PEKK was forced to slide against metal foils in a benchmarked friction tester at different rates, normal pressures and temperatures. The typical friction response, exhibiting a shear stress overshoot followed by a steady-state region, did not qualitatively change when applying a Marbocote 227CEE release agent on the metal foils. However, the overshoot reduced and, in case of a high normal pressure of 45 kPa, the steady-state response lowered as well. Thus, release agent should be included for a more accurate characterization of tool-ply friction. A longer heating time resulted in a large increase of the overshoot, whereas the steady-state response was nearly unaffected. The same observation was made when testing at a higher temperature, which may suggest that the increase in overshoot is due to increased adhesive bonding. Moreover, a change in adhesive bonding could also explain the lower overshoot observed when a release agent was applied, indicating adhesion as a key mechanism for tool-ply friction.
Robotic-Assisted Measurement of Fabrics for the Characterization of the Shear Tension Coupling
Authors: Langat K. Rogers , De Luycker Emmanuel , Noureddine Farid , Rakotondrabe Micky
Published: July 2022

Industrial use of composite materials requires an increasingly advanced knowledge of technical textiles mechanical properties to control the manufacturing process and guarantee the performances of the finished products. Among the qualities that influence greatly the shaping process, theshear deformability is key for the forming of complex composite parts with double curves geometries. On the other hand, the stiffening of the behavior as the shearing rise is responsible for the occurrence of the wrinkling defect. This shearing behavior of the textile reinforcement is difficult to determinebecause it is non-linear and it coexists with a tensile stiffness of the fibers that is several orders of magnitude higher. Furthermore, shear and tension are coupled due to the weaving of the textiles. Now, few experimental methods have been proposed to measure the tension behavior of fabric as a function of its shear level because dedicated devices are needed for this investigation, capturing the shear-tension coupled behavior of fabric is then a difficult task. This paper deals with the robotization of the fabric shear-tension effect characterization. A KUKA robot associated with a force/torque sensor is utilized, taking advantage of its benefits in the ability to control the state of yarn tensions during shear tests while keeping track of the desired trajectory as enabled by the hybrid position-force control feature. This ensures precise positioning of a sample fabric and accurate contact forces. An anisotropic hyperelastic constitutive model for fabrics, based on the continuum theory of mechanics that takes into account the shear-tension coupling effect was formulated analytically and numerically simulated using Matlab software. An experimental test was then implemented to validate the proposed model. The results from a uni-axial tensile test and shear test under constant uni-axial tensile loading were obtained and analyzed to characterize the test sample. The model parameter identification was performed and presented in detail.
A Materials Science-Based Approach to Finite Element Simulation of Warm-Forming of Al-Mg-Zn Alloys
Authors: Grabner Florian , Österreicher Johannes
Published: July 2022

Warm deep-drawing of pre-aged (under-aged) blanks of 7xxx series aluminum alloys (Al-Zn-Mg) at moderate temperatures of roughly 120–230°C is a promising route for producing parts with considerable geometrical complexity, good paint bake hardening response, and, thus, excellent final mechanical properties. Furthermore, oil-based lubricants can be used, eliminating the need for elaborate cleaning routines. However, finite element (FE) simulation of the process is challenging: time-temperature regimes during coupon testing for material cards should closely follow the real conditions in the press because the material undergoes significant changes at warm-forming temperatures, such as recovery and precipitation/coarsening/reversion of hardening phases. When convective heating is used for Nakajima or tensile testing, heating rates are usually too low to adequately represent real process conditions (where inductive or contact heating may be used). Here we present a method for establishing FE material cards and calibrating the GISSMO damage model using miniaturized tensile specimens for a dilatometer with inductive heating. The simulations are compared with warm deep-drawing experiments of pre-aged 7xxx and good agreement of minimum draw temperature for two alloys is achieved. The findings are discussed with regards to transmission electron microscopy investigations and final mechanical properties published earlier. It was found that warm-forming is suitable to produce complex 7xxx parts with high final strength. Conditions in the press can be represented by using miniaturized tensile specimens and inductive heating for calibration of material cards/damage models.
A Simulative Method for Studying the Bonding Condition of Friction Stir Extrusion
Authors: Bocchi Sara , D'Urso Gianluca Danilo , Giardini Claudio , Maccarini Giancarlo
Published: July 2022

In the manufacturing industry, the problem related to the management of metal waste is of considerable importance, since it is produced in large quantities during mechanical processing.However, its recovery is not always a simple task, especially with regard to the metal cutting processes. In fact, due to the presence of surface oxide and contaminating oily residues, the recovery process of these components is often very expensive and polluting. This problem can be solved with the FSE process, patented in 1993 by The Welding Institute. The FSE can be counted among the main innovative processing techniques developed in Industry 4.0, as it involves only metal scraps coming from the machining processes as starting material, without providing for their preliminary re-melting in a billet form, and it uses only the heat generated by the friction between the tool and the metal. Since FSE is a quite recent process, the development of simulative models is useful for understanding its basic mechanisms. The objective of this research is to analyze if and how the bonding phenomena occour considering both the thermal and the stress conditions involved and generated by the process parameters.As a result, FEM analysis proved to be a valid tool to correctly forecast if bonding phenomena really take place and how process parameters affect the bonding quality. Moreover, it was possible to confirm that the Piwnik and Plata bonding model is a good criterion for predicting the effects of this technology.
Acoustic Performances of Polymers Hierarchical Structure Produced with Material Jetting Technology
Authors: Levi Elisa , Piana Edoardo Alessio , Giorleo Luca
Published: July 2022

This research is aimed at testing the ability of high-end 3D printers to reproduce complex structures having some acoustic performances in terms of sound absorption and sound transmission loss. Specifically, some experiments were made on four different types of geometries to compare their acoustic behaviour. The sound absorption and sound insulation of the samples have been evaluated by means of a four-microphone impedance tube. The adopted technique allows to retrieve the transfer matrix of each specimen and then, through a composition of the matrices, to virtually determine the acoustic performances of any arrangement of the different samples. The experiments revealed promising results in terms of quality, finishing and precision of the jetting process, highlighting benefits and critical issues related to the acoustic performances.
Flow Behaviour of Carbon Fibre Sheet Moulding Compound
Authors: Qian C.C. , Yuan Hao , Jesri Mona , Khan Muhammad , Kendall Kenneth N.
Published: July 2022

The growing popularity of SMC compression moulding in the automotive industry has led to great interests in process simulation model development. Existing process simulation models are commonly adapted from models originally developed for short fibre composites and lacking experimental validation data. A novel material model specifically developed for SMC flow simulation is proposed in this paper, where the experimental material characterisation is performed using the squeeze flow testing method. The model is validated through simulation of the squeeze flow testing and the accuracy of the model is assessed by comparing the predicted compression forces against experimental data collected from the squeeze flow testing. The proposed new model has demonstrated significant improvement in comparison to existing commercial models in term of compression force prediction, but the predicted compressive forces diverted away from the experimental values towards the end of the test. The predicted cavity pressure distribution has also been investigated and compared to observations reported in the literature where good correlation between predicted pressure distribution and the literature have been achieved.
Investigation of the Plane Strain Behaviour of a Laser-Heat Treated Aluminium Alloy
Authors: Piccininni Antonio , Lattanzi Attilio , Rossi Marco , Palumbo Gianfranco
Published: July 2022

The necessity of complex-shaped components characterized by superior mechanical properties and limited weight is moving the attention to the Aluminium (Al) alloys. Deep Drawing Steel grades possess superior stamping characteristics and formability with respect to Al alloys. But the need of light-weighting pushes towards the adoption of materials with optimal strenght-to-weight ratio, like Al alloys. Todays Al alloys are certainly used in the transport sector but their formability (at room temperature) is poorer than Deep Drawing Steel grades, which still hinders their massive implementation in the forming processes and drives the research toward innovative manufacturing solutions. One of the most promising approach to overcome such a limitation and, thus, manufacture complex component using cold forming processes, is the adoption of local heat treatments to obtain a suitable distribution of material properties able to enhance the formability at room temperature.The design of cold forming using locally modified blanks needs: (i) an extensive investigation of the material behaviour at room temperature after the local heating and (ii) the adoption of a Finite Element approach. As for the former aspect, the authors proposed a fast and comprehensive methodology to investigate the hardening behaviour of an Al alloy (AA5754-H32) locally annealed by laser heat treatment. Using a similar approach, the hardening model was then enriched by considering the normal anisotropy, evaluating the correlation between the Lankford parameter and the material condition reached at the end of the local treatment. To improve the knowledge on the plastic response of the material, the present work focusses on the characterization of the plane strain behavior of the AA5754, initially in wrought condition (H32) and subsequently modified by laser heating. In particular, the study proposes a new quasi-homogeneous specimen which combines the local heating profile with an optimized geometry to produce a prevailing plane strain condition in the heat-treated zone. In such a way, data about the material response in the plane strain condition could be obtained for a large range of material conditions determined by the preliminary heat treatment.