Drawing Velocity Research Articles

Subthalamic stimulation modulates context-dependent effects of beta bursts during fine motor control

Increasing evidence suggests a considerable role of pre-movement beta bursts for motor control and its impairment in Parkinson’s disease. However, whether beta bursts occur during precise and prolonged movements and if they affect fine motor control remains unclear. To investigate the role of within-movement beta bursts for fine motor control, we here combine invasive electrophysiological recordings and clinical deep brain stimulation in the subthalamic nucleus in 19 patients with Parkinson’s disease performing a context-varying task that comprised template-guided and free spiral drawing. We determined beta bursts in narrow frequency bands around patient-specific peaks and assessed burst amplitude, duration, and their immediate impact on drawing speed. We reveal that beta bursts occur during the execution of drawing movements with reduced duration and amplitude in comparison to rest. Exclusively when drawing freely, they parallel reductions in acceleration. Deep brain stimulation increases the acceleration around beta bursts in addition to a general increase in drawing velocity and improvements of clinical function. These results provide evidence for a diverse and task-specific role of subthalamic beta bursts for fine motor control in Parkinson’s disease; suggesting that pathological beta bursts act in a context dependent manner, which can be targeted by clinical deep brain stimulation.

Residual Stress Engineering for Wire Drawing of Austenitic Stainless Steel X5CrNi18-10 by Variation in Die Geometries-Effect of Drawing Speed and Process Temperature.

As a result of conventional wire-forming processes, the residual stress distribution in wires is frequently unfavorable for subsequent forming processes such as bending operations. High tensile residual stresses typically occur in the near-surface region of the wires and can limit further application and processability of the semi-finished products. This paper presents an approach for tailoring the residual stress distribution by modifying the forming process, especially with regard to the die geometry and the influence of the drawing velocity as well as the wire temperature. The aim is to mitigate the near-surface tensile residual stresses induced by the drawing process. Preliminary studies have shown that modifications in the forming zone of the dies have a significant impact on the plastic strain and deformation direction, and the approach can be applied to effectively reduce the process-induced near-surface residual stress distributions without affecting the diameter of the product geometry. In this first approach, the process variant using three different drawing die geometries was established for the metastable austenitic stainless steel X5CrNi18-10 (1.4301) using slow (20 mm/s) and fast (2000 mm/s) drawing velocities. The residual stress depth distributions were determined by means of incremental hole drilling. Complementary X-ray stress analysis was carried out to analyze the phase-specific residual stresses since strain-induced martensitic transformations occurred close to the surface as a consequence of the shear deformation and the frictional loading. This paper describes the setup of the drawing tools as well as the results of the experimental tests.

An effective ANN-based hybrid fiber diameter control approach with gated recurrent units and selective weight optimization

Reducing fiber diameter inconsistencies has been the focus of much research in the fiber manufacturing industry. However, the structure of the fiber drawing machine (FDM) leads to time delays in traditional diameter control methods, thereby making it difficult to achieve satisfactory results. Moreover, traditional methods apply only a single adjustment to control the diameter precision, i.e., drawing velocity, and ignore the crucial impact of furnace temperature on diameter. To address these issues and improve the control precision, we propose a novel hybrid diameter control model that uses an artificial neural network (ANN) as the main framework and integrates bidirectional gated recurrent units (BiGRUs) and a new mechanism known as selective weight optimization (SWO). Specifically, due to the irreplaceable role of diameter prediction in the control task, we adopt BiGRU to predict fiber wire diameter and utilize the results as a supplemental data input to the control policy network. Due to the high complexity of the input data, the ANN-based network is introduced as the policy network to analyze the inherent relevance of the data and provide two separate control strategies, i.e., drawing velocity adjustment and furnace temperature adjustment. Additionally, a selective weight optimization (SWO) mechanism that combines these two strategies and selectively optimizes the weights is proposed to further improve diameter control precision. The effectiveness of the BiGRU-ANN-SWO is extensively evaluated using four various real-world experiments. Results indicate that the BiGRU-ANN-SWO achieves considerably more precise and robust control of fiber diameter compared with existing approaches.

Cold Drawing of AISI 321 Stainless Steel Thin-Walled Seamless Tubes on a Floating Plug.

The paper presents the results of an analysis of the process of drawing AISI 321 stainless steel thin-walled seamless tubes on a floating plug. The influence of the geometry of dies and plugs, drawing velocity, and lubricants on the possibility of carrying out the pipe drawing process without a loss of strength of the lubricating film and, consequently, disturbance of the forming process and tube cracking, and also on the temperature in the drawing process, the mechanical properties of the tubes drawn, and the microhardness and roughness of the inner and outer surface of the tubes was investigated. The parameters of the drawing tools used were as follows: angle of drawing dies α = 16° and floating plugs with angles of inclination of the conical part of the plug β = 11.5°, 13°, and 14°. The drawing dies and floating plugs were made of G10 sintered carbide. Drawing speed was varied over the range 1 to 10 m/min. The study used several lubricants. Tubes with dimensions (outer diameter D0, wall thickness g0 before drawing process) D0 = 19 mm, g0 = 1.2 mm and D0 = 18 mm, g0 = 1.2 mm were drawn to produce tubes with dimensions (outer diameter Dk, wall thickness gk after drawing process) Dk = 16 mm, gk = 1.06 mm on a drawbench with the same total elongation, while the diameter and wall thickness were changed. During the process, continuous measurements were made of the drawing force and temperature in the deformation zone and on the tube surface. It was found that the drawing process causes a decrease in the roughness parameters Ra and Rz of the inner surface of the tubes. Moreover, after drawing, an increase of 30-70% was observed in the microhardness of the tube material in relation to the microhardness of the charge material. Based on the test results, it can be concluded that the work of frictional forces is the main direction of optimization of tube drawing on a floating plug process of hard-deforming materials.

Bioinspired Robust Helical‐Groove Spindle‐Knot Microfibers for Large‐Scale Water Collection

AbstractHelical structure is ubiquitous in nature with high‐order configuration, specific paths, large superficial areas, providing an approach to bioinspired wettability control. Owing to its special hydrophilic rough surfaces and periodic knot and joint structure, natural spider silk can catch tiny droplets in fog and transport them directionally, sparking scientific interest in bioinspired knotted microfibers to address the risk of water scarcity. To further enhance the water collection ability, a bioinspired helical‐groove‐modified spindle‐knot (HSK) microfiber is continuously fabricated in this work by a simple coating method combined with crack regulation. The formation and morphology can be precisely manipulated by adjusting the drawing velocity and concentration of the coating solution. Compared with smooth spindle‐knot microfibers, HSK exhibits greater performances of wetting speed, droplets growth rate, and hanging ability, which can be attributed to the unique helical paths that bring capillary force difference and offer extra three‐phase contact line lengths for water collection behavior. The maximum droplet volume is almost 2114 times that of the microfiber knots, which is the highest compared with previous reports. Moreover, HSK microfibers are endowed with repairable wettability, long‐term durability, excellent mechanical properties, and flexibility, showing great potential in the realm of applications for large‐scale water collection.

Optimization and prediction of lead removal from aqueous solution using FO–MD hybrid process: Statistical and artificial intelligence analysis

Heavy metals (HMs) has become one of the most serious pollutants that are harmful to the environment and ecology. This paper focused on the removal of lead contaminant from wastewater by forward osmosis–membrane distillation (FO–MD) hybrid process using seawater as draw solution. Modeling, optimization, and prediction of FO performance are developed using complementary approach based on response surface methodology (RSM) and an artificial neural network (ANN). FO process optimization using RSM revealed that under initial lead concentration of 60 mg/L, feed velocity of 11.57 cm/s and draw velocity of 7.66 cm/s, FO process achieved highest water flux of 6.75 LMH, lowest reverse salt flux of 2.78 gMH and highest lead removal efficiency of 87.07%. Fitness of all models was evaluated based on determination coefficient (R2) and mean square error (MSE). Results showed highest R2 value up to 0.9906 and lowest RMSE value up to 0.0102. ANN modeling generates the highest prediction accuracy for water flux and reverse salt flux, while RSM produces the highest prediction accuracy for lead removal efficiency. Subsequently, FO optimal conditions are applied on FO–MD hybrid process using seawater as draw solution and evaluate their performance to simultaneously remove lead contaminant and desalination of seawater. Results displays that FO–MD process shows a highly efficient solution to produce fresh water with almost free heavy metals and very low conductivity.

Numerical Simulation of Microstructure Evolution of Directionally Annealed Pure Iron by Cellular Automata

In order to understand the effects of drawing velocity, initial grain size and texture on the microstructure evolution during directional annealing, a cellular automata model based on grain boundary (GB) curvature, GB energy and GB mobility was established with a modified calculation model of the GB curvature. The simulation results show that there is a lower limit and an upper limit to the drawing velocity for the formation of columnar grains, and the columnar grains can only be formed between the upper limit and the lower limit. The simulation results are consistent with the experimental results. When the drawing velocity is lower than the lower limit, the equiaxed grains grow at the front of the hot zone, which hinders the formation of the columnar grains. With the increase of initial grain size, the driving force of GB migration decreases, and the grain boundaries are difficult to move with the hot zone, which is not conducive to the formation of columnar grains. There is an upper limit of initial grain size for the formation of columnar grains. The abnormal growth induced by texture prevents the growth of columnar grains during directional annealing. The weaker the texture strength, the more conducive to the growth of columnar grains.

Effects of Contact Conditions at Wire–Die Interface on Temperature Distribution during Wire Drawing

The effects of contact conditions at the wire–die interface on the temperature distribution of the specimen and die are investigated to understand the wire drawing process. Finite element analysis and experiments are performed to analyze the temperature distribution of a drawn wire and die based on different contact conditions using a low-carbon steel wire. The maximum temperature (Tmax) of the die decreases as the contact heat transfer coefficient at the wire–die interface increases, whereas that of the wire increases with the contact heat transfer coefficient. The Tmax of the die and wire decreases with the thermal conductivity of the die. As the thermal conductivity of the die increases, the heat generated by friction is rapidly absorbed into the die, and the Tmax of the die decreases, thus resulting in a decrease in the surface temperature of the wire. The Tmax of both the die and wire linearly increases with the friction factor. In particular, the Tmax of the die more sensitively changes with the friction factor compared with that of the wire. The Tmax of the die linearly increases with the drawing velocity, whereas that of the wire parabolically increases with the drawing velocity. The influence of bearing length on the temperature increase in both the wire and die is insignificant.

Abnormal grain growth of FeMnAlNiCo shape memory alloys during directional recrystallisation

Polycrystalline FeMnAlNi-based alloys generally exhibit poor pseudoelasticity owing to grain constraint. A promising method to improve the pseudoelasticity involves increasing the grain size by directional recrystallisation (DR). To improve the efficiency of obtaining large grain size, the effect of DR parameters—hot zone temperature (HZT) and drawing velocity—on the columnar grain size and the mechanisms of grain growth were investigated. The results showed that samples of FeMnAlNiCo shape memory alloys (SMAs) with an average grain size of over 20 mm and the largest grain size exceeding 50 mm were obtained after DR. The apparent activation energy of the columnar grain growth for DR was ≈135 kJ/mol, which was much lower than that of the equiaxed grain growth for isothermal annealing (≈384 kJ/mol). The lateral growth of the columnar grains was probably because the boundaries between columnar grains tend to form random high-angle grain (HAG) boundaries. By incremental compression test, at an applied strain of 7.0%, nearly <104> oriented single crystal exhibited a recoverable strain of ≈6.0%, while the polycrystal had a recoverable strain of only ≈3.4%. This work provides important guidance and inspires new strategies for microstructural control in FeMnAlNi-based SMAs.

Preliminary validity of the Draw a Shape Test for upper extremity assessment in multiple sclerosis.

To validate the smartphone sensor-based Draw a Shape Test - a part of the Floodlight Proof-of-Concept app for remotely assessing multiple sclerosis-related upper extremity impairment by tracing six different shapes. People with multiple sclerosis, classified functionally normal/abnormal via their Nine-Hole Peg Test time, and healthy controls participated in a 24-week, nonrandomized study. Spatial (trace accuracy), temporal (mean and variability in linear, angular, and radial drawing velocities, and dwell time ratio), and spatiotemporal features (trace celerity) were cross-sectionally analyzed for correlation with standard clinical and brain magnetic resonance imaging (normalized brain volume and total lesion volume) disease burden measures, and for capacity to differentiate people with multiple sclerosis from healthy controls. Data from 69 people with multiple sclerosis and 18 healthy controls were analyzed. Trace accuracy (all shapes), linear velocity variability (circle, figure-of-8, spiral shapes), and radial velocity variability (spiral shape) had a mostly fair/moderate-to-good correlation (|r|=0.14-0.66) with all disease burden measures. Trace celerity also had mostly fair/moderate-to-good correlation (|r|=0.18-0.41) with Nine-Hole Peg Test performance, cerebellar functional system score, and brain magnetic resonance imaging. Furthermore, partial correlation analysis related these results to motor impairment. People with multiple sclerosis showed greater drawing velocity variability, though slower mean velocity, than healthy controls. Linear velocity (spiral shape) and angular velocity (circle shape) potentially differentiate functionally normal people with multiple sclerosis from healthy controls. The Draw a Shape Test objectively assesses upper extremity impairment and correlates with all disease burden measures, thus aiding multiple sclerosis-related upper extremity impairment characterization.

Thermoplastic micro-forming process of bulk metallic glass surgical blades using drawing velocity regulation

Drawing velocity is essential in the manufacturing of the multi-facet bulk metallic glass (BMG) knife edges used in corneal surgery since it is one of the factors that can determine good blade profiles in the thermoplastic forming process. The goal of this article is to determine and regulate drawing velocity based on the viscoelastic filament stretching and knowledge of the thermoplastic forming map of BMG. The generation of drawing velocity profile is done in two stages: the initial transient stage before the extensional viscosity stage is fully developed, and the extensional viscosity stage. The controller based on the system identification of the testbed is then optimized from the requirements of the drawing velocity and its implementation feasibility. The control objectives of regulation performance and robustness to modeling uncertainties are posed and solved in an optimal control ( H∞) framework. The proposed controller shows an improvement over other controllers including proportional-integral-derivative controllers in terms of robustness to uncertainties and tracking performance. BMG samples processed from this study result in good quality with improvement of 20% and 54% in X–Y ([Formula: see text] µm) and X–Z ([Formula: see text]µm) straightness and 25% more consistent edge radii ([Formula: see text] nm).

Cardiovascular and cerebrovascular responses to urodynamics testing after spinal cord injury: The influence of autonomic injury.

Autonomic dysfunction is a prominent concern following spinal cord injury (SCI). In particular, autonomic dysreflexia (AD; paroxysmal hypertension and concurrent bradycardia in response to sensory stimuli below the level of injury) is common in autonomically-complete injuries at or above T6. AD is currently defined as a >20 mmHg increase in systolic arterial pressure (SAP) from baseline, without heart rate (HR) criteria. Urodynamics testing (UDS) is performed routinely after SCI to monitor urological sequelae, often provoking AD. We, therefore, aimed to assess the cardiovascular and cerebrovascular responses to UDS and their association with autonomic injury in individuals with chronic (>1 year) SCI. Following blood draw (plasma norepinephrine [NE]), continuous SAP, HR, and middle cerebral artery blood flow velocity (MCAv) were recorded at baseline (10-minute supine), during standard clinical UDS, and recovery (10-minute supine) (n = 22, age 41.1 ± 2 years, 15 male). Low frequency variability in systolic arterial pressure (LF SAP; a marker of sympathetic modulation of blood pressure) and cerebral resistance were determined. High-level injury (≥T6) with blunted/absent LF SAP (<1.0 mmHg2) and/or low plasma NE (<0.56 nmol•L−1) indicated autonomically-complete injury. Known electrocardiographic markers of atrial (p-wave duration variability) and ventricular arrhythmia (T-peak–T-end variability) were evaluated at baseline and during UDS. Nine participants were determined as autonomically-complete, yet 20 participants had increased SAP >20 mmHg during UDS. Qualitative autonomic assessment did not discriminate autonomic injury. Maximum SAP was higher in autonomically-complete injuries (207.1 ± 2.3 mmHg) than autonomically-incomplete injuries (165.9 ± 5.3 mmHg) during UDS (p < 0.001). HR during UDS was reduced compared to baseline (p = 0.056) and recovery (p = 0.048) only in autonomically-complete lesions. MCAv was not different between groups or phases (all p > 0.05). Cerebrovascular resistance index was increased during UDS in autonomically-complete injuries compared to baseline (p < 0.001) and recovery (p < 0.001) reflecting intact cerebral autoregulation. Risk for both atrial and ventricular arrhythmia increased during UDS compared to baseline (p < 0.05), particularly in autonomically-complete injuries (p < 0.05). UDS is recommended yearly in chronic SCI but is associated with profound AD and an increased risk of arrhythmia, highlighting the need for continued monitoring during UDS. Our data also highlight the need for HR criteria in the definition of AD and the need for quantitative consideration of autonomic function after SCI.

Modeling the relationship between forward osmosis process parameters and permeate flux

Artificial neural networks (ANN) models are becoming more popular than mathematical and transport-based models due to their high performance and accuracy. Previous literature shows a lack of application of powerful ANN techniques for predicting forward osmosis (FO) performance. In this study, we developed a feedforward network to predict and analyze the permeate flux in the FO process. The ANN model was developed based on a lab-scale experimental database from various published articles. The permeate flux was modeled as a function of membrane-type, membrane orientation, feed and draw solution molarity, feed and draw velocity, molecular weight, feed solution temperature, and draw solution temperature. The influence of foulants on permeate flux has not been considered for developing the ANN model to avoid over-complication of the present work. The adj. R-squared values for train, unseen test and total datasets are 0.99, 0.92, and 0.95, respectively. These values are higher than those found in previously published literature (0.97, 0.85, and 0.82). Moreover, this is the first time that the effect of individual variables on permeate flux has been estimated quantitatively.

Effects of Drawing Direction and Angle on Stability of Point-To-Point Drawing Task Varying Length of Drawing for the Elderly

The aim of the present study was to show the effects of drawing direction (top-down vs. bottom-up) and angle of trace participant drew (0 vs. 60 vs. 300) on stability varying length of drawing (5.7 cm vs. 11.4 cm vs. 17.1 cm) for the elderly. These three independent variables were within-subject factors. Thirty-eight older adults (18 females, 20 males; mean age = 71.7, SD = 5.5) participated in the study. The drawing task was performed on a computer with touch screen, using an electronic pen. Drawing performance was analyzed using a 3-way repeated measures ANOVA model. Results indicated that the error for top-down was significantly larger than that for bottom-up condition; the error for the length of drawing at 5.7 cm was larger than those at 11.4 cm and 17.1 cm. Data analysis also revealed that the effect of drawing direction on drawing velocity, indicating that drawing velocity for bottom-up was significantly greater than that for top-down condition. Additionally, the drawing velocity of length of drawing was significantly greater for 17.1 and 11.4 cm than it was for 5.7 cm. The angle of trace participant drew also significantly affected drawing velocity: 60 yielded significantly greater velocity than did 0 and 300 conditions. These results have implications for product and interface design for the elderly.

Fabrication of Silica Optical Fibers: Optimal Control Problem Solution

In this work, a new approach to solving problems of optimal control of manufacture procedures for the production of silica optical fiber are proposed. The procedure of silica tubes alloying by the Modified Chemical Vapor Deposition (MCVD) method and optical fiber drawing from a preform are considered. The problems of optimal control are presented as problems of controlling distributed systems with objective functionals and controls of different types. Two problems are formulated and solved. The first of them is the problem of the temperature field optimizing in the silica tubes alloying process in controlling the consumption of the oxygen–hydrogen gas mixture (in the one- and two-dimensional statements), the second problem is the geometric optimization of fiber shape in controlling the drawing velocity of the finished fiber. In both problems, while using an analog to the method of Lagrange, the optimality systems in the form of differential problems in partial derivatives are obtained, as well as formulas for finding the optimal control functions in an explicit form. To acquire optimality systems, the qualities of lower semicontinuity, convexity, and objective functional coercivity are applied. The numerical realization of the obtained systems is conducted by using Comsol Multiphysics.

Optimization of Die Design to Abolish Surface Defect on Telescopic Front Fork (TFF) Tube

Background: The telescopic fork is mainly used for suspension purposes in different devices to absorb the vibration and disturbances which come from the road or mechanical devices. Factors such as die angle, drawing velocity, lubrication, and area reduction per pass significantly affect the drawing loads and residual stresses formed in the drawn tube during the tube drawing process. Objective: An instantaneous transverse crack was found on the pipe's outer surface during the drawing process in the current work, and the key challenges were to reduce the percentage of pipe rejection. Methods: In this work, optimum drawing die designs were proposed by using the Finite Element Method (FEM). The FEM solving tool is called Abaqus, and it has been used for simulating and solving the cold-rolling process. The FEM model of cold drawing process is generated in Abaqus with the same boundary condition (Axial load and constrain) as used on the actual wire drawing machine. Result: With current die geometry, there was a substantial reduction in area, axial stress (Tensile) along the die side is 672 MPa, which is 23 % lower than the current die axial stress value 877 MPa. There was 48 % plastic strain found along the purposed die side, which was 17 % lower than the existing strain of 64%. Finally, the area was reduced by changing the die geometry from the current level of ~52% to 35 to 40 %. Conclusion: By reducing the area (35 to 40 %) in the output tube, and strain (17 %), it was possible to abolish the transverse crack on the pipe's outer surface. As part of the optimisation of the FEM work process, this work gives us encouraging results. Further research will be considered for future work.

Impact of draw velocity profile on footprint definition for primary rock

In block/panel caving mines the footprint geometry and the undercut level height are key planning elements that have a bearing on the project final value. Selection of these parameters obviously depends on the economic objective, but it is also strongly influenced by rock mass characteristics that define column extraction capacity from draw points. This paper presents a simple methodology that allows defining the footprint and the best height of draw (BHOD) based on column extraction velocities, which are defined with the aim of controlling mass rock dynamic response while caving is propagated. The proposed methodology can be used by industry because of the ease of application. A study case is presented for a block model which is evaluated by both the proposed methodology and nominal profit estimation.

Adaptive wire diameter control of the high-precision optical fibre drawing machine

Different from the conventional methods such as the Proportional-Integral-Derivative (PID)-based method, an adaptive control algorithm (ACA) is proposed in this paper to control the wire diameter of high-precision fibre drawing machines (FDMs). A simple FDM model is established to acquire the relationship between fibre diameter and drawing velocity before the ACA is introduced. The comparison simulation of the accuracy of fibre diameter between the proposed ACA and traditional PID is made, and the ACA is applied to actual fibre drawing processes, so as to validate the ACA. The comparative results show that the fluctuation of filament diameter is smaller and the accuracy is higher under the ACA control. In actual fibre filament drawing processes, the ACA can limit the diameter error within ±2μm, which meets the production requirements.

Numerical Analysis and Investigation on the Drawbending Springbackand Fracture

In this paper, the effect of process parameters on the drawing springbackand fracture mechanism of high strength steel in drawbending process was investigated. The fracture behaviour and fracture morphology were observed and analyzed using Scanning Electron Microscope (SEM). The process parameters studied in this paper includes drawing speed, roll radius, drawing force and roll radius. The springback angle measurement method for drawing springback was also introduced and applied. The conclusions were drawn from the results. The drawbending springback angle increases withthe increase of drawing velocity. The springbackdecreases with the increase of the round roll. The large bending angle leads to the large springback. The large tension force can decrease the springback angle. The springback increases with the increase of the drawing distance. The fracture with theplane angle of 60 indicates a shear fracture and thedominated brittleness mode, which is induced by a large radius against thickness value. The fracture vertical to straight side indicates the ductility tension fracture, which is induced by a small radius against thickness value.

Influence of a drawbead passage in deep drawing processes on surface values and the tribological system

In recent times, lightweight design and functional integration in metal forming and especially in deep drawing operations lead to complex geometries. These geometries can cause variable defects in production. Especially with modern materials like AHSS or UHSS, deep drawing becomes more challenging. One common way to meet these challenges and manufacture sheet metal parts without defects is the application of drawbeads in the forming tool. Drawbeads are used for an exact control and forecast of the material flow during the deep drawing process. It was already shown, that different material parameters like the tensile strength and the fracture strain are changed significantly after running through a drawbead. In addition, there are various indications that the tribological system in a drawbead passage is also changed significantly and that this has further influence on the ongoing drawing process.This assumption is examined with an experimental setup derived from industrial deep drawing processes. Therefore, different sheet metal materials are drawn through a drawbead geometry under the same conditions like the blank holder force, the drawing velocity or lubrication. After the drawbead passage, 3D surface parameters are measured and compared to the values in its initial state. Following, conventional strip-drawing tests with preloaded strips are carried out. The variation of the friction coefficient after a drawbead passage is analysed and compared to the initial state. The results are correlated with the surface values. For these investigations, three different materials are used: a conventional deep drawing steel because of its wide application as well as an advanced high strength steel AHSS and an aluminium alloy of the 6xxx series as representatives for modern lightweight materials.