Stack Compression Research Articles

Effect of the loading-rate and stress state on the constitutive modelling and fracture of 2205 Duplex stainless steel

Shear cutting is a high-speed forming process where material separation is involved. The nature of the process leads to high strain rates and temperatures on the sheared zone of the material subjected to the operation. In this work, the mechanical behavior in terms of flow stress, plastic deformation and fracture of a 2205 Duplex stainless steel sheet is determined. Uniaxial tension, uniaxial compression, stack compression, plane strain tension and simple shear tests at different angles with respect to the rolling direction of the metal sheet are performed to determine the anisotropic behavior of the material. Strain rate and temperature dependence of the flow stress and the plastic behavior of the material is determined through notched tensile tests performed under various temperatures (20°C, 100°C, 300°C and 500°C) and strain rates (0.001 s-1, 10 s-1 and >100 s-1). Finally, fracture behavior under various stress states is determined through notched tensile, central hole, in-plane shear and plane strain tests. The temperature and strain rate dependence of the fracture behavior is determined through notched tensile, in-plane shear and plane strain tests performed under various temperatures (20°C, 100°C, 300°C and 500°C) and strain rates (0.001 s-1, 10 s-1 and >100 s-1). The anisotropic behavior and work hardening of the material are modelled by the Hill48 yield function and Swift-Hockett-Sherby hardening law, respectively. Among the two ductile fracture models tested, Hosford-Coulomb model showed the best agreement and is therefore used to account for the temperature and strain rate effects on the fracture behavior. By combining these three models, an accurate reproduction of the mechanical behavior of the 2205 Duplex stainless steel sheet is achieved.

Effect of the Slenderness Relation on In-Plane Deformation in Stack Compression Tests

In forming technologies and their simulation, knowing the flow curve characteristic of the material is an essential parameter. Acquiring this knowledge is particularly challenging for sheet materials in high strain ranges. It is well-known that friction and geometric relationships have a distorting effect on the flow curves, thus compensation is necessary. However, the geometric ratio can not only influence the formation of the flow curve, if our material shows anisotropic behaviour. In our research, using compression tests, we examined the deformation relations of deformed specimens through digital imaging methods. The stack compression test is widely used to determine the flow curve in a broad range of large deformation. During the test, several disk specimens with the same geometric characteristics were stacked on top of each other to form a final test piece, and then compression tests were conducted on these assemblies. We found that at low values of the geometric ratio (0.1 in our study), the proportion of plastic, planar principal strains indicating anisotropic behaviour is greater than at higher geometric ratios (0.5 and 1.0 in our study).

Relevance of GDL Properties Regarding GDL Quality Assurance

Gas diffusion layers are an important part of all types of polymer electrolyte membrane fuel cells (LT-PEMFC, HT-PEMFC or AEMFC). Albeit the conversion reaction is not taking place in the GDL the contributions of the GDL to the function of the cell are essential. So, the GDL needs to homogenise the distribution of reacting gases over the electrode area compensating inhomogeneities created by the channel fin structure of the flow-field of the bipolar plate and at the same time cause a focussing of product streams towards the channels. The GDL needs to conduct electric current between the catalyst layer and the bipolar plate at high current density and transport released thermal energy. The GDL also needs to distribute mechanical pressure of the stack compression.In order to accomplish all those tasks, the GDL needs to feature the right properties with high homogeneity through-out its area and with high reproducibility batch to batch. Unfortunately, a rather high number of properties can be assigned to a GDL. So, the review paper by Yuan et al. on properties for different LT-PEMFC components1 lists about 15 different properties for GDL which influence their function. As many of these properties are difficult to measure measuring all of them is not a viable approach to the quality assurance of GDL as part of their industrial production.Within the project QM-GDL Fraunhofer ICT together with the other partners of the project is analysing the relevance of the different properties, comparing the expected impact of deviation from the designed values and the effort, and determining the actual values. The goal is to determine the most relevant parameters which will allow to assure proper functioning of the GDL if their values are controlled keeping the effort for measurements at a reasonable value.In the presentation the approach for the selection of relevant parameters will be explained at a number of examples. Also, a tentative list of parameters will be presented and discussed.The presented work is part of the project QM-GDL which receives financial support by the German Federal Ministry of Digital Infrastructures and Traffic under Grant Agreement 03B11016E. The content of the presentation is in the sole responsibility of the author. X.-Z. Yuan, C. Nayoze-Coynel, N. Shaigan, D. Fisher, N. Zhao, N. Zamel, P. Gazdzicki, M. Ulsh, K. A. Friedrich, F. Girard and U. Groos, Journal of Power Sources, 491 (2021).

A Nanogenerator Enabled by a Perfect Combination and Synergetic Utilization of Triboelectrification, Charge Excitation and Electromagnetic Induction to Reach Efficient Energy Conversion

AbstractTriboelectric–electromagnetic hybridized nanogenerator (TEHG) is confirmed as an effective energy harvesting for Internet of Things. However, it is still a great challenge to gain a high‐output triboelectric‐nanogenerator (TENG) and to perfectly combine TENG with electromagnetic generator (EMG). Herein, a TEHG composed of space confined multi‐layer‐stack TENG (SM‐TENG) and stack compression promoted flux change EMG is proposed. The interaction of magnets on the rotor with the magnets on the stator makes contact–separation of the SM‐TENG and changes the magnetic flux of EMG in rotation process, reducing wear and deformation of TENG. A voltage multiplier circuit (VMC) with a Zener diode is employed to enhance SM‐TENG performance and maintain stable output. The output charge and current of four SM‐TENG units reach 3.2 µC and 385 µA at rotatory speed 60 rpm, and the voltage of four EMG reaches 8.09 V. The perfect combination and synergetic utilization of triboelectrification, charge excitation, and electromagnetic induction in a single device are realized. The integrated TEHG can power 12 bulbs (2 W) and 16 thermo‐hygrometers, and a Bluetooth thermo‐hygrometer to transmit wireless signals to a mobile phone. This work provides a new strategy for high efficient integration and utilization various mechanisms in one energy‐harvesting device.

Hydrogen crossover in proton exchange membrane electrolysers: The effect of current density, pressure, temperature, and compression

In this paper, the hydrogen crossover through the membrane, which is a major concern from the safety, durability, and efficiency viewpoints, in proton exchange membrane (PEM) electrolysers, is investigated. It is well-documented that hydrogen crossover rate increases by pressure, temperature, and current density. However, how current density affects the hydrogen crossover rate is yet to be fully understood. The effect of current density on hydrogen crossover is usually attributed to hydrogen supersaturation and enhanced hydrogen pressure on the membrane due to the pressure drop through the catalyst layer and liquid/gas diffusion layer (LGDL). However, other parameters, as suggested by recent research studies, can have an important role to play. Here, by developing an analytical model, the effects of several parameters are investigated. The findings from this study suggest that hydrogen crossover is affected by the increase in the membrane temperature, hydrogen supersaturation, and compression of the LGDL. The effect of membrane temperature increase with current density on hydrogen crossover was found to be pronounced at current densities above 2 A cm−2. The increase in hydrogen supersaturation with current density was found to be the main cause of hydrogen crossover during electrolysis. Stack compression increases the hydrogen crossover rate mainly by reducing the mass transfer coefficient and hence the hydrogen supersaturation. The effect of increased hydrogen pressure on the membrane is more noticeable at low operating pressures; however, in general, does not have a major impact on the hydrogen crossover. It is also suggested that the hydrogen length of the diffusion path should also include the ionomer of the CL in addition to the membrane thickness. The findings of this research help with a better understanding of the hydrogen crossover during PEM electrolysis that can be considered during material selection and design of the cell components. This helps with reducing the crossover rate to improve efficiency and durability and ensure safe operations.

Development and Testing of High Performance Nylon12 (PA12) Based Natural Fiber Composites

Kenaf based nylon 12 (PA12) composites were successfully made using hydroentanglement and film stack compression molding. The combination of natural fibers with an engineering polymer with a relatively low melting temperature can potentially have high strength and modulus composites. The chopped kenaf fibers were treated in a NaOH solution. The NaOH treatment is used to improve the roughness of the surface and also expose cellulose fibers within the fibers to help improve bonding with the resin. Tensile tests of samples with treated and untreated fibers with a fiber weight fraction of 40% show that the treated fiber composite has an improvement of 13% and 18% in its strength and modulus respectively. The resulting fibers were used to make preforms using hydroentanglement process. The process of hydroentanglement is typically used in making paper products. The use of this process to make composite materials using chopped fibers is a very unique approach adopted for this research. Three different fiber weight fractions were looked at namely 40%, 50% and 60%. Tensile and flexure testing of the samples showed a consistent increase with an increase in the fiber weight fraction. Morphological characterization of the fibers showed that treatment removed excess fluff and dirt and also had striations on the fiber which would lead to better fiber wet-out. SEM images of the fractured surface of the sample with 50% by weight of kenaf fibers showed that there was some fiber bundling as expected leading to dry zones within the composite which could potentially lead to crack initiation. The novelty of the research is developing preforms using chopped natural fibers using hydroentanglement process and the ability to combine these natural fibers with low melting point PA 12 leading to obtaining high strength composite without compromising the structural integrity of the kenaf fibers.

Influence of a Hydrostatic Pressure Shift on the Flow Stress in Sheet Metal

The stack compression test (SCT) and the strain-rate controlled hydraulic bulge test (HBT) enable to determine the large strain flow curve of sheet metal under an identical deformation mode and balanced biaxial tension. This equivalence should lead to identical flow behavior if plastic yielding is independent of the hydrostatic stress. However, a discrepancy is observed in the flow curves of DP600 steel sheet determined by the SCT and the HBT. In order to avoid uncertainty with respect to dissimilar test conditions, the average strain-rate in both material tests is carefully controlled. Additionally, evidence is provided that friction can be sufficiently minimized yielding a homogeneous SCT up to a true plastic strain of 0.3. Assuming reliable experimental data, the hypothesis that the hydrostatic pressure shift between the stress states in the SCT and the HBT causes the observed difference in flow behavior is scrutinized. Theoretical considerations regarding the effect of a superimposed hydrostatic pressure (i.e. putting a material under a pressure environment for a certain stress state) on the flow stress, as suggested by Spitzig et al. [1] and Spitzig and Richmond [2], are used to understand the effect of a pressure shift between two stress states on the flow stress. Finally, the theoretical considerations are experimentally validated using the discrepancy in flow behavior of DP600 measured by the SCT and the HBT.

Improving performance in PEMFC by applying different coatings to metallic bipolar plates

In the present study, aluminum plates were coated with three different materials using thermal spray in order to be used as bipolar plate in proton exchange membrane fuel cells (PEMFC). NiCr, NiCrBSi, and (Co,Ni)CrAlY were selected as coating materials due to their high corrosion resistance. High velocity oxy-fuel (HVOF) was the spray coating method used in the present study. Accelerated corrosion resistance and interfacial contact resistance (ICR) tests were conducted on the coatings under simulated PEMFC conditions. The corrosion current density of the bipolar plates coated with NiCrBSi, NiCr, and (Co,Ni)CrAlY, on Al-substrate in the simulated cathodic environment of a proton-exchange membrane fuel cell (PEMFC) were found to be −4.98 (1.03 E−5), −3.89 (0.00012), and −2.91 (0.0012) A/cm2, respectively. Also Ecorr for NiCr, NiCrBSi and (Co,Ni)CrAlY were −0.36, −0.31 and −0.39 (±0.01) volt. The electrochemical impedance spectroscopy (EIS) and polarization curves show that the NiCrBSi coating has higher corrosion resistance than other coatings. The interfacial contact resistance between the NiCrBSi and NiCr coated samples and carbon paper are the smallest on typical fuel cell stack compression force of 140 N/cm2. Then, long-term durability tests were conducted on single cell with coated bipolar plates. The results showed a considerably better performance and no decrease in cell voltage in the single cell with NiCrBSi coated bipolar plates. It can be concluded that the performance of NiCrBSi alloy coated bipolar plate developed using HVOF coating is acceptable in fuel cells as bipolar plate.

Coupled stress–strain and transport in proton exchange membrane fuel cell with metallic bipolar plates

Metallic bipolar plates (BPPs) for proton-exchange membrane fuel cells (PEMFCs) are desirable in automotive applications because they (i) offer good mechanical properties and manufacturability, (ii) reduce costs compared with graphite-based BPPs, and (iii) allow flexible flow-channel designs that increase power density. In this study, the relatively unexplored couplings between the mechanical and electrochemical effects due to stack compression were analyzed using a model that accounts for the transport, electrochemical reaction, heat transfer, and stress mechanics. The present model is aimed to be employed into simulation tools for PEMFC design and application. Both the tilt angle and flow-channel width of the BPPs were found to affect the stress distribution in the gas-diffusion layer (GDL) and BPP, as well as the contact resistance. The coolant pressure affected the stress distribution in the BPP, particularly at the welded joint between two adjacent plates. Stack compression not only increased the mass-transfer resistance of the GDL, particularly under the rib region, but also resulted in improved heat transfer, which reduced the PEMFC temperature and improved the uniform temperature distribution. Although the impacts of compression on the heat and mass transfer became more pronounced at higher current densities, the combined effect with the reduced membrane temperature and contact resistance between the GDL and BPP resulted in improved PEMFC performance. Applying the model to investigate a range of mechano-electrochemical conditions revealed that higher stress–strain concentrations resulted in a more nonuniform current–density distribution at the interface between the microporous layer and catalyst layer.

Failure strains of anisotropic thin sheet metals: Experimental evaluation and theoretical prediction

In the present study, experimental and theoretical analyses were performed to predict the failure strain of EDD and AA5052 sheet metals. In this context, uniaxial tensile tests and stack compression tests were conducted to assess the anisotropic constants of two different yield models viz. Hill48 and Yld2000-2d. Further, the calibrated models were used to estimate the directional properties and yield loci of the investigated sheet metals, and the results were successfully validated with the experimental data. Additionally, the forming limit diagram (FLD) and fracture forming limit diagram (FFLD) were analytically predicted using Marciniak–Kuczyński (MK) model and Bao–Wierzbicki (BW) ductile damage model implementing different yield theories. The estimated failure limits were compared with the experimental necking and fracture strain data obtained from the punch stretching (PS) tests, and found that the theoretical models incorporating Yld2000-2d yield theory best described the experimental limiting strains. Furthermore, the best predicted MK-FLD and BW-FFLD was used for failure strain analyses of three different sheet metal forming experiments such as two-stage forming, single point incremental forming (SPIF) and deep drawing. It was observed that the MK-FLD and BW-FFLD failed to predict the necking and fracture strain of different pre-strained sheets in the principal strain locus. Hence, all the strain data were transposed into polar effective plastic strain (PEPS) locus using Yld2000-2d yield model, and the PEPS based failure limit was developed. It was found that the MK-FLD and BW-FFLD predicted the respective limiting strains in PEPS locus efficiently. Moreover, all the experimental fracture strains were converted into 3D stress triaxiality locus and concluded that the calibrated BW fracture loci had a good predictive efficiency of all the fracture strains obtained from various forming tests.

Necking and fracture limit analyses of different pre-strained sheet materials in polar effective plastic strain locus using Yld2000-2d yield model

This paper aims to estimate and analyze both the necking and fracture based path-independent forming limit criteria during two-stage forming of anisotropic sheet materials. In this context, in-house experimental setups were fabricated to impart pre-strain along three distinct strain paths viz. equi-biaxial, plane strain and uniaxial in different automotive grade sheet materials namely EDD, AA5052 and DP600. Uniaxial tensile and stack compression tests were conducted, and the test results were used to evaluate the eight anisotropic coefficients of Yld2000-2d yield model. The predicted evolutions of the yield loci and both the strength and plastic strain ratio (r-value) directionalities of the pre-strained materials were calibrated with experimental data. In the second stage of deformation, all pre-strained sheet materials were stretch formed up to the onset of necking and further until the initiation of fracture. Correspondingly, the forming limit diagram (ε-FLD) and fracture forming limit diagram (ε-FFLD) were experimentally evaluated. The necking and fracture limit of as-received materials was theoretically predicted incorporating calibrated Yld2000-2d yield model in the geometrical imperfection based Marciniak-Kuczynski (MK) model and ductile fracture based Bao-Wierzbicki (BW) damage model, respectively. It is noteworthy that the dynamic shifting of pre-strained ε-FLDs and ε-FFLDs has been recorded in principal strain space (ε1, ε2) depending on the type and amount of pre-strain. Hence, the polar effective plastic strain (PEPS) based necking (PEPS-FLD) and fracture (PEPS-FFLD) limits were estimated using Yld2000-2d anisotropy plasticity theory, and it was observed that the shift of the limiting strains was restricted successfully. It was found that the maximum absolute error during necking and fracture dome height prediction of pre-strained materials was restricted up to 5% and 6%, respectively, when PEPS based failure limits were used as damage model in FE simulation.

Prediction of earing defect and deep drawing behavior of commercially pure titanium sheets using CPB06 anisotropy yield theory

Recently, sheet metal forming industries have shown interest in characterization of anisotropy properties, tension-compression strength differential and deep drawing behavior of commercially pure titanium (CP Ti) material for successful fabrication of lightweight components. In present work, the formability of 1.0 mm thick CP Ti sheet metal was studied using a laboratory scale deep drawing test set-up, and the limiting drawing ratio (LDR) was found to be 2.143. Four ears were observed in the LDR cup with maximum cup height along diagonal direction (DD) and troughs along both rolling direction (RD) and transverse direction (TD), and the earing height was approximately 13.7% of the total cup height. Tensile and stack compression tests were carried out along different orientations to evaluate the anisotropy properties and tension-compression strength differential, and these data were used to develop the CPB06 constitutive yield model. Also, the developed CPB06 anisotropy plasticity theory was implemented in an FE model to predict the non-uniform material flow, earing defect and thickness distribution successfully. In order to reduce earing defect, a two-stage blank modification technique was proposed incorporating directionalities of both yield strength and plastic strain ratio. A significant 83% reduction in earing height was achieved through use of modified blank with simultaneous benefit of improvement in thickness distribution and reduction in peak load.

Equivalent Stiffness Model of a Proton Exchange Membrane Fuel Cell Stack Including Hygrothermal Effects and Dimensional Tolerances

Proton exchange membrane fuel cells (PEMFCs) require mechanical compression to ensure structural integrity, prevent leakage, and to minimize the electrical contact resistance. The mechanical properties and dimensions of the fuel cell vary during assembly due to manufacturing tolerances and during operation due to both temperature and humidity. Variation in stack compression affects the interfacial contact pressures between components and hence fuel cell performance. This paper presents a one-dimensional equivalent stiffness model of a PEMFC stack capable of predicting independent membrane and gasket contact pressures for an applied external load. The model accounts for nonlinear component compression behavior, thickness variation due to manufacturing tolerances, thermal expansion, membrane expansion due to water uptake, and stack dimensional change due to clamping mechanism stiffness. The equivalent stiffness model is compared to a three-dimensional (3D) finite element model, showing good agreement for multicell stacks. Results demonstrate that the correct specification of gasket thickness and stiffness is essential in ensuring a predictable membrane contact pressure, adequate sealing, and avoiding excessive stresses in the bi-polar plate (BPP). Increase in membrane contact pressure due to membrane water uptake is shown to be significantly greater than the increase due to component thermal expansion in the PEMFC operating range. The predicted increase in membrane contact pressure due to thermal and hydration effects is 18% for a stack containing fully hydrated Nafion® 117 membranes at 80 °C, 90% relative humidity (RH) using an eight bolt clamping design and a nominal 1.2 MPa assembly pressure.

Finite element design procedure for correcting the coining die profiles

This paper presents a new finite element based design procedure for correcting the coining die profiles in order to optimize the distribution of pressure and the alignment of the resultant vertical force at the end of the die stroke. The procedure avoids time consuming and costly try-outs, does not interfere with the creative process of the sculptors and extends the service life of the coining dies by significantly decreasing the applied pressure and bending moments. The numerical simulations were carried out in a computer program based on the finite element flow formulation that is currently being developed by the authors in collaboration with the Portuguese Mint. A new experimental procedure based on the stack compression test is also proposed for determining the stress-strain curve of the materials directly from the coin blanks.

Implementation of Yld96 anisotropy plasticity theory for estimation of polar effective plastic strain based failure limit of pre-strained thin steels

In present work, tensile and stack compression tests were performed along different orientations to evaluate the yield behaviour and strength directionalities of several equi-biaxial, plane strain and uniaxial pre-strained extra deep drawing (EDD) thin steel sheets. Strain based forming limit diagrams (ε-FLD) were evaluated by deforming along six different paths with strain ratio ranging from 0.91 to −0.34, and the dynamic shift of failure strains was established with the cusp moved equal to the amount and direction of minor strain component of the pre-strained materials. Hence, polar effective plastic strain based FLD (PEPS-FLD) was estimated using the Yld96 anisotropy plasticity theory to restrict the dynamic shift of failure strains irrespective of the amount and type of pre-strain. Unlike ε-FLD, the consideration of PEPS-FLD along with Yld96 anisotropy coefficients of as-received EDD steels in FE model was encouraging to predict the limiting dome height (LDH) close to experimental data within 6% error. Also, insights into the role of effective plastic strain consumed and strain path on decrease in LDH of pre-strained steels were analysed.

Validation of a fuel cell compression spring equivalent model using polarisation data

Fuel cell stack compression is a vital part of the manufacturing process, however limited research exists in predicting the optimal compression force to maximise fuel cell performance. This paper validates a spring equivalent model proposed in a previous publication which, when coupled with literature derived gas diffusion layer (GDL) optimal compression data, can predict the compression force required based on gas diffusion layer and gasket properties. The error between the model and the optimal performance of the stack is a maximum of 6.4%. This is a positive indication as to the model's validity. In addition, the compression homogeneity applied by the compression system to the flow field plate is measured to confirm the GDL is experiencing the predicted compression force. The impact of this research is a reduction in development time and cost as less empirical testing will be required to identify optimal fuel cell stack compression.

On the Utilization of Circle Grid Analysis in Thin-walled Forming of Tubes: Experimental and Numerical Evaluation

Abstract This paper presents an investigation on different tube forming processes by plastic deformation, including expansion, reduction and inversion of tube ends, using circle grid analysis in order to obtain strain-loading paths in different regions of the principal strain space. The experimental work was carried out on commercial AA6063-T6 tubes and includes independent material characterization by means of tensile, stack compression and instability tests. Finite element modelling of the tube forming processes by means of an in-house computer program gives support to the presentation and allows assessing the overall accuracy, validity and reliability of using circle grid analysis to investigate formability and failure in tube forming.

Multidisciplinary approaches to metallic bipolar plate design with bypass flow fields through deformable gas diffusion media of polymer electrolyte fuel cells

In this study, multidisciplinary approaches to optimizing serpentine gas flow channels stamped on sheet metal with various design parameters (i.e., channel-to-rib width ratio, draft angle, inner fillet radius, and channel depth) are implemented to identify the fluid–structure interaction characteristics of locally deformed gas diffusion media (GDM) and the rate of entropy generation for bypass flow through the porous GDM. First, static structural analysis is conducted to demonstrate the GDM deformation by stack compression and its mechanical effects on fluidic properties of GDM experimentally and numerically. The GDM-channel model results agree with the experimental results within a maximum error of less than 10%. Emphasis is placed on understanding how the reactant gas flow through GDM effectively transports the oxygen gas to catalyst layers. Next, parametric studies are conducted to identify the dominant design effects on the fluidic performance over the entire computational domain. Subsequently, a design optimization method is applied to obtain the most favorable flow channel designs with trapezoidal cross-sections. In the optimized serpentine channel design, the maximized oxygen transport ratio is predicted to be 0.718 at the interface between the GDM and catalyst layers under the constraint of total pressure drop.

Alkylpurine glycosylase D employs DNA sculpting as a strategy to extrude and excise damaged bases.

Alkylpurine glycosylase D (AlkD) exhibits a unique base excision strategy. Instead of interacting directly with the lesion, the enzyme engages the non-lesion DNA strand. AlkD induces flipping of the alkylated and opposing base accompanied by DNA stack compression. Since this strategy leaves the alkylated base solvent exposed, the means to achieve enzymatic cleavage had remained unclear. We determined a minimum energy path for flipping out a 3-methyl adenine by AlkD and computed a potential of mean force along this path to delineate the energetics of base extrusion. We show that AlkD acts as a scaffold to stabilize three distinct DNA conformations, including the final extruded state. These states are almost equivalent in free energy and separated by low barriers. Thus, AlkD acts by sculpting the global DNA conformation to achieve lesion expulsion from DNA. N-glycosidic bond scission is then facilitated by a backbone phosphate group proximal to the alkylated base.

Numerical and Experimental Determination of Cut-edge after Blanking of Thin Steel Sheet of DP1000 within Use of Stress based Damage Model

The proposed study focuses on blanking of thin steel sheets of Dogal1000DP +Z100MBO. Numerical and experimental investigations of the influence of clearance and punch speed on the cutting force and the geometry of the sheared edge were done. Tensile and stack compression test at elevated temperatures has been chosen to determine the flow and fracture behavior of Dogal1000DP +Z100MBO at different stress states. It is shown that the flow curve determined by stack compression test leads to better results in force - displacement prediction of a blanking process compared to determination of flow curve by tensile test. Stress based fracture criterion were chosen to describe damage behaviour. Moreover significant influence of fracture locus for negative stress triaxialities on the geometry of the numerically predicted sheared edge is shown.