bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of the materials based on protein fibers in a low-pressure high-frequency plasma flow
Authors: Rakhmatullina G R , Pankova E A , Fukina O V , Khayytov M , Chapaeva L V 
Published: May 2022

Abstract
The effect of low-pressure high-frequency (HF) plasma treatment on the structure of the materials formed by bundles of natural protein (collagen) fibers is considered. The outer surface of the material is being affected by a constant flow of ions and a pulse-periodic flow of electrons. During this procedure the electrons flow at opposite sides of the sample in antiphase. This leads to that an alternating electric field is created, which intensity is estimated approximately at 105 V/m, inside the material. As a result, in the capillaries and pores, a breakdown occurs and charged particles are forming during this process. The recombination of these particles releases an energy of 15.76 eV on the surface of pores and capillaries, which is transferring to the surface molecules of the protein, which leads to the bulk modification of the material based on protein fibers. Such volumetric processing provides an effective modification of structural elements, allowing you to significantly improve the quality of liquid treatments in the production of collagen-containing materials and their properties in general.
Comparison of the Smallest Squares and Smallest Modules Methods in Modeling Processing of Materials by Plasma of a Gas-Vapor Discharge with Liquid Electrodes
Authors: Takseitov R R , Galimova R K , Yakupov Z Y 
Published: May 2022

Abstract
This paper describes the application of the least squares and least modulus methods to obtain the values of the power parameters of the central Lennard-Jones potential when modeling processes in the technology of processing materials with vapor-gas discharge plasma with a liquid electrode.
New approach for the identification of anisotropy material parameters using hydraulic bulge tests
Authors: Khalfallah A , Zoueghi SA , Fernandes JV 
Published: May 2022

Abstract
This paper put forwards a new method for the identification of the flow curves of anisotropic sheet metals using hydraulic bulge tests throughout circular and elliptical dies. This method is based on the membrane equilibrium equation, numerical simulation to derive the pole thickness and experimental data involving the measurement of only the polar deflection versus the applied hydraulic pressure curves. The experimental curves of four hydraulic bulge tests were obtained: one bulge test through circular die, and three bulge tests through elliptical dies, where the major axe of the elliptical die was oriented in three directions with respect the rolling direction of the sheet metal. These results were used in the identification of flow parameters and anisotropy coefficients of Hill48’ yield criterion. Then, FEA was utilized to perform sensitivity analysis of material parameters on the different hydraulic bulge test responses. The case study was a sheet metal of low carbon steel DC04. The identified material parameters were used in the numerical simulation of hydraulic bulge tests for the accuracy verification of the proposed method. It was shown a good agreement between model’s prediction and experimental results.
Investigation of the impact of process parameters on the layer formation of AlSi coated boron-manganese steel
Authors: He F , Merklein M 
Published: May 2022

Abstract
Hot stamping has established itself as a technology for manufacturing safety-relevant car body components. Its usage has found increased importance due to rising political and social pressure e.g. for improved fuel conservation. Due to reduced sheet thickness, hot stamping parts offer lightweight solutions while at the same time providing improved crash performance due to their high strength. Boron-manganese steel is commonly used in hot stamping processes. Due to hot scale formation during heat treatment and the subsequent forming process, additional coatings, typically AlSi-coatings, are applied. Since hot stamped parts are formed at temperatures of 600 °C to 800 °C no suitable lubricants have yet been found. This leads to increased friction and severe wear in the process, which negatively affect tool lifetime and overall part quality. Additionally, process temperatures influence the layer formation and surface roughness due to diffusion processes. A deeper process understanding is needed to acquire detailed knowledge of the resulting impact on tribological behavior. Within this study, the effect of coating thickness on the resulting layer is analyzed by comparing the resulting material composition and surface roughness. To this end, the layer formation and surface roughness are analyzed for two different layer thicknesses (AS150 and AS80) in relation to furnace temperature, holding time and heat up rate. Both are characterized by means of heating experiments conducted on an annealing furnace. The change in layer composition and surface roughness are determined via metallographic investigation and tactile measurement. The results of this study help to improve the process understanding of the tribological conditions within the hot stamping process and to develop future measures for reducing tool wear.
U-channel forming of an 7075-T6 in warm conditions
Authors: Royne S , Laurent H , Maillard A 
Published: May 2022

Abstract
The use of high mechanical strength aluminum coupled with the warm forming process makes it possible to replace certain steel parts in vehicles, thus reducing its mass and consequently greenhouse gas emissions. Warm forming of aluminum alloys requires heating the part between 150°C and 250°C to increase formability and reduce springback. In this study, a 7075-T6 alloy U-channel part was warm formed at 200°C in a short enough time to maintain the T6 state of the material. The process consisted of successively performing the heating by contact and stamping steps on the same mechanical press. From a thermomechanical characterization of the alloy in the temperature range between RT and 200°C and several strain rates, numerical simulations of the forming of the U-channel part were carried out using Abaqus. The experimental springbacks reduced with temperature were in agreement with the numerical simulations. An analysis of the conductivity and hardness of the material showed also that the 7075 keeps its T6 state until 10 s of warm forming.
Process Stability and Application of 1900 MPa Grade Press Hardening Steel with reduced Hydrogen Susceptibility
Authors: Rosenstock D , Gerber T , Castro Müller C , Stille S , Banik J 
Published: May 2022

Abstract
While 22MnB5 with aluminium silicon (AS) coating was established as the quasi-standard in press hardening many years ago, the need for steels that offer even higher strength is growing. These needs include corrosion protection of the automotive component and scale prevention during processing in hot forming lines. However, the processing of AS coated ultra-high strength steels involves demands for the furnace atmosphere. Reducing the hydrogen susceptibility and increasing the material strength at the same time was the driving force for the development of MBW 1900 + AS Pro. The paper focuses on the process stability of this steel concerning furnace and stamping parameters as well as the hydrogen induced cracking resistance under different dew points in the furnace atmosphere. In addition, the potential by means of different partial press hardening processes is presented. With tailored tempering, locally heated tools can be used to achieve soft areas in the part. Furthermore, the application potential of MBW 1900 + AS Pro in tailor welded blanks is shown.
Comparison of three different ductile damage models for deep drawing simulation of high-strength steels
Authors: Behrens B-A , Rosenbusch D , Wester H , Althaus P 
Published: May 2022

Abstract
High-strength steels are increasingly used in deep drawing for automotive parts due to their improved strength properties. To increase the formability and thus extend the process limits, a deep drawing process with additional force transmission has been developed. For a numerical optimisation of the considered process, an exact modelling of the failure behaviour is essential. The forming limit curve (FLC) is widely used to predict the onset of necking in sheet metal forming. However, the validity of the FLC is limited to the case of linear strain paths. Therefore, the scope of past investigations has been on failure modelling depending on the stress state. This article presents the experimental-numerical characterisation of the failure behaviour of the high-strength steels HCT600X and HX340LAD. Tensile tests with butterfly specimens were carried out under varying stress states and simulated with ABAQUS to parametrise the stress-based models Johnson-Cook (JC), Modified Mohr-Coulomb (MMC) and DF2016. An additional experiment was carried out to evaluate the models in terms of predicted outcome accuracies by comparing the onset of fracture in the simulation with the experimental findings. In future investigations, the improved damage modelling will be applied in a deep drawing simulation with additional force transmission to optimise the process design.
Analytical approach to damage prediction in incremental sheet metal forming
Authors: Bharti Sahil , Raneesh Deepu , Krishnaswamy Hariharan , Panigrahi Sushanta Kumar 
Published: May 2022

Abstract
Incremental sheet metal forming (ISF) is known to exhibit higher formability compared to conventional stamping. It is established that the mechanism of failure during ISF is by fracture occurring at higher effective strain than the local necking observed in traditional forming processes. The deformation limit in ISF is therefore estimated numerically using a suitable continuum damage model. However, simulation of incremental forming process including the damage model is often computationally expensive. In the present work, a simpler alternative combining finite element simulation and numerical solution outside finite element software is utilized. The finite element simulation is performed ignoring the damage model. The stress and strain history thus obtained in critical locations is utilized to estimate the damage evolution. The proposed method is useful when utilizing uncoupled continuum damage models. The proposed method is validated for typical cases by comparing it against the predictions from finite element method. Excellent correlation is observed between the proposed method and finite element simulation results.
Measurement of edge fracture strain of dual-phase steels by in-plane bending test
Authors: Masoumi Khalilabad M , Perdahcioğlu E S , Atzema EH , van den Boogaard AH 
Published: May 2022

Abstract
Edge ductility of dual phase steels is highly affected by the preparation of the edge and especially shear cutting has a detrimental effect on the formability. In this study, a novel in-plane bending test is used to characterize the edge ductility of dual-phase steels. Digital image correlation technique is employed to calculate the fracture strain along the edge in the desired material orientation. The proposed test setup isolates the material-dependent aspects, namely damage and hardening, from those resulting from testing procedure factors such as contact stresses and friction compared to conventional hole expansion capacity (HEC) test. The results show that the edge crack phenomenon depends on the material orientation.
Adjustment of fracture locus to improve edge crack resistance
Authors: Habibi Niloufar , Münstermann Sebastian 
Published: May 2022

Abstract
Edge crack sensitivity of advanced high strength steels is posing challenges in forming the sheets with shear-cut edges. In fact, cutting process reduces formability of material by leaving residual damage at the cut edges and makes it prone to edge cracking. The difficulty of the problem mainly lies in the complex loading path that sheets undergo through shear-cutting and the subsequent forming processes. In other words, the stress state evolves from pure-shear to plane-strain during cutting process and changes to mostly uniaxial tension during the following hole-expansion test. The present study aimed to investigate the physical mechanism underlying the formation of edge cracks. The overall aim of the study is to tailor an improved microstructural configuration leading to a significantly reduced edge crack sensitivity. As a first step in this process, an artificial fracture locus is iteratively identified which promises to improve edge crack resistance. In this regard, a dual phase steel was considered as reference material and its fracture locus was calibrated based on uncoupled Bai-Wierzbicki fracture model. The artificial fracture locus representing a virtual material with improved edge crack resistance changed in a way that lower residual damage was inherited from the cutting process, which consequently improved the hole-expansion ratio.
On the topology design of a mechanical heterogeneous specimen using geometric and material nonlinearities
Authors: Gonçalves M , Andrade-Campos A , Thuillier S 
Published: May 2022

Abstract
Material characterization and the calibration of constitutive models play an important role in the majority of the forming processes nowadays. For an accurate virtualization of the processes, the material mechanical behavior needs to be known a priori. The classical characterization procedure involves carrying out several standard mechanical tests to identify the required information about the material. However, this procedure turns out to be expensive and time-consuming. Heterogeneous mechanical tests have been used to overcome this issue. By providing richer information with a reduced number of tests, their use can enhance the actual material characterization process. This work aims at making a significant contribution towards this goal by designing a heterogeneous mechanical test using topology optimization. A specimen topology is obtained with a heterogeneous displacement field by applying the theory of compliant mechanisms. Due to the large displacements considered, a geometrically nonlinear finite element analysis and a topology optimization procedure are proposed. Material nonlinearity is taken into account as well, to design solutions closer to reality. An optimal mechanical test with a highly heterogeneous strain field is obtained and evaluated, considering its diversity, using mechanism theory and a mechanical indicator.
Metamodeling of a deep drawing process using conditional Generative Adversarial Networks
Authors: Link Patrick , Bodenstab Johannes , Penter Lars , Ihlenfeldt Steffen 
Published: May 2022

Abstract
Optimization tasks as well as quality predictions for process control require fast responding process metamodels. A common strategy for sheet metal forming is building fast data driven metamodels based on results of Finite Element (FE) process simulations. However, FE simulations with complex material models and large parts with many elements consume extensive computational time. Hence, one major challenge in developing metamodels is to achieve a good prediction precision with limited data, while these predictions still need to be robust against varying input parameters. Therefore, the aim of this study was to evaluate if conditional Generative Adversarial Networks (cGAN) are applicable for predicting results of FE deep drawing simulations, since cGANs could achieve high performance in similar tasks in previous work. This involves investigations of the influence of data required to achieve a defined precision and to predict e.g. wrinkling phenomena. Results show that the cGAN used in this study was able to predict forming results with an averaged absolute deviation of sheet thickness of 0.025 mm, even when using a comparable small amount of data.
Predicting Dynamic Process Limits in Progressive Die Sheet Metal Forming
Authors: Budnick D , Ghannoum A , Steinlehner F , Weinschenk A , Volk W , Huhn S , Melek W , Worswick M 
Published: May 2022

Abstract
Tool makers have a limited selection of tools and are afforded limited flexibility during progressive die try-outs when attempting to identify suitable process control parameters and optimize throughput. The performance of a given tooling design hinges on selecting a suitable stroke rate for the press. Cost efficiencies are realized when operating a press at higher stroke rates, but risk subjecting the sheet metal strip to larger, uncontrolled oscillations, which can lead to collisions and strip-misalignment during strip progression. Introducing active control to the strip feeder and lifters can offer increased flexibility to tool makers by allowing the strip progression to be fine-tuned to reduce strip oscillations at higher stroke rates. To alleviate uncertainties and assist in fine-tuning the process control parameters, machine learning models, such as an artificial neural network, are constructed to predict whether a given set of process parameters will lead to a collision or strip-misalignment during the strip progression. The machine learning models are trained using a dataset of FEA simulations which model the same progressive die operation using different process control inputs for the feeder, lifter and press. The machine learning models are shown to be capable of predicting the outcome of a given process permutation with a classification accuracy of about 87 % and assist in identifying the dynamic process limits in the progressive die operation.
Digital Twins in deep drawing for virtual tool commissioning and inline parameter optimization
Authors: Klingel Lars , Penter Lars , Mayer Philip , Ihlenfeldt Steffen , Verl Alexander 
Published: May 2022

Abstract
Fluctuating boundary conditions and the highly nonlinear process behavior of deep drawing operations make experience-based selection of suitable control parameters difficult. Nowadays, commissioning deep drawing tools, i.e., die spotting and identification of suitable control parameters for defect-free parts, is conducted on real world try-out presses. Transferring the tools to production machines entails adaption of these initial parameters. Once production is ramped up, any changes to material properties, lubrication and press behavior require continuous manual machine parameter tuning. Virtual tool commissioning and utilizing these simulation models in the production phase to adapt control parameters would reduce time and cost over the entire life cycle of the machine and the tool sets. The virtual representative, which provides services for a plant over several life cycle phases, is also referred to as Digital Twin. In this paper, the authors present a Digital Twin concept for deep drawing presses to predict the state of the system and optimize the control parameters during the production. The integration of all involved subsystems into one system simulation and its efficient calculation is the biggest challenge. The authors combine a virtual commissioning simulation tool with a finite element model to implement all relevant properties of the deep drawing press and the interaction of its subsystems. It is shown, how the idea of a system simulation makes predictions of system parameters specific to a production situation possible, and therefore, can help to select suitable control parameters that leads to a reduction of the error rate in deep drawing.
Advanced Springback Compensation Strategy through elimination of avoidable elastic strain energy
Authors: Birkert A , Zimmermann P , Hartmann B , Nowack M 
Published: May 2022

Abstract
The stamping of dimensionally accurate sheet metal body components still represents a huge challenge in the automotive industry. This is partly caused by the multi-stage production process which complicates the design of an appropriate compensation strategy dramatically. A key prerequisite of an appropriate compensation strategy is to eliminate any undesired influence of elastic energy being potentially induced when closing the blankholders in the several operations throughout the production process. Here, a universally applicable compensation strategy is presented which fulfils this requirement thoroughly; by applying this process, the involved strain energy is reduced to a minimum due to proper part position in all operations. Technically this compensation strategy is achieved by, first, simulating all operations of the stamping process individually, second, by individually calculating the springback after each operation and, third, by accumulating the calculated deviation vector fields for each operation appropriately, which are then used for springback compensation. The process is time and cost effective and the required efforts are moderate even for complicated multistage stamping operations.
Superposing tensile stresses into single point incremental forming to affect martensitic transformation of SS304
Authors: Mamros E M , Maaß F , Hahn M , Tekkaya A E , Ha J , Kinsey B L 
Published: May 2022

Abstract
Superposing pre-stress on a SS304 sheet metal blank in biaxial tension and performing a single point incremental forming operation on the stretched blank is investigated experimentally. By applying a pre-stress to the sheet metal blank prior to incremental forming, the resulting microstructural change can be affected to obtain functionally graded materials according to the intended application. In austenitic stainless steels, this variation of the stress states alters the phase transformation, specifically the martensitic transformation kinetics, by influencing key process parameters, such as process force, temperature, and equivalent plastic strain. The phase transformation in truncated square pyramids is measured using magnetic induction. These measurements validate the effectiveness of the stress superposition method for achieving the desired mechanical properties based on altering the final microstructure of a simple geometry.
Evaluation of electronic and optical behavior of the interface of Co2FeAl/AlN heusler alloy
Authors: Lahoupour F , Boochani A 
Published: May 2022

Abstract
Based on the density functional theory, the electronic, optical, and structural properties of the Co2FeAl/AlN Interface have been studied. It is shown that the Co2FeAl compound is a half-metal with 100% spin polarization at the Fermi level, and the growth of this compound on the AlN semiconductor changes its stability. The best interface connection from the point of view of stability occurs in the Co-Co-Al case, which has a semi-metallic and spin polarization of the interface, which candidate it for spintronic applications. The optical properties of this interface show that it can benefit medical and sensor devices because of its anisotropic optical properties at low energies. In the infrared, visible, and ultraviolet ranges, the optical energy loss functions are zero or very little, which referred to its candidate for optical applications in these energy ranges.