Characterising material and process variation effects on springback robustness for a semi-cylindrical sheet metal forming process

Souza, T. de; Rolfe, Bernard

doi:10.1016/j.ijmecsci.2010.09.009

Cited by 27 publications

(11 citation statements)

References 19 publications

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“…They were able to achieve an excellent reduction in spring back value of 0.038 mm with redesigned elliptical core. de Souza et al [12] carried out stochastic simulations to quantify the contribution of process parameters -Blank Holder Pressure (BHP) and coefficient of frictionand mechanical material properties -Yield stress and Ultimate strengthon spring back of an auto-mobile component. They showed changes in process parameters resulted in changes in strain component thus effecting the magnitude of external work applied to forming system.…”

Section: Introductionmentioning

confidence: 99%

Obtaining manufactured geometries of deep-drawn components through a model updating procedure using geometric shape parameters

Balla

Coox²,

Deckers³

et al. 2018

Mechanical Systems and Signal Processing

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The vibration response of a component or system can be predicted using the finite element method after ensuring numerical models represent realistic behaviour of the actual system under study. One of the methods to build high-fidelity finite element models is through a model updating procedure. In this work, a novel model updating method of deep-drawn components is demonstrated. Since the component is manufactured with a high draw ratio, significant deviations in both profile and thickness distributions occurred in the manufacturing process. A conventional model updating, involving Young's modulus, density and damping ratios, does not lead to a satisfactory match between simulated and experimental results. Hence a new model updating process is proposed, where geometry shape variables are incorporated, by carrying out morphing of the finite element model. This morphing process imitates the changes that occurred during the deep drawing process. An optimization procedure that uses the Global Response Surface Method (GRSM) algorithm to maximize diagonal terms of the Modal Assurance Criterion (MAC) matrix is presented. This optimization results in a more accurate finite element model. The advantage of the proposed methodology is that the CAD surface of the updated finite element model can be readily obtained after optimization. This CAD model can be used for carrying out analysis, as it represents the manufactured part more accurately. Hence, simulations performed using this updated model with an accurate geometry, will therefore yield more reliable results.

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Section: Introductionmentioning

confidence: 99%

Obtaining manufactured geometries of deep-drawn components through a model updating procedure using geometric shape parameters

Balla

Coox²,

Deckers³

et al. 2018

Mechanical Systems and Signal Processing

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show abstract

“…The variation of material properties can be detected within a batch or from batch-to-batch [9]. For a robust process layout in FEsimulation it is not of importance if the variations' effects on the part feasibility occur from part to part, run-to-run or from begin to end of run of a series process, as it is defined in [10]. Within this work it is of interest to analyse the effect of material variations on the feasibility for the forming process in general.…”

Section: Introductionmentioning

confidence: 99%

Variation of deep drawing steel grades’ properties in dependency of the stress state and its impact on FEA

Goedel

Merklein

2011

Int J Mater Form

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In industrial sheet metal forming processes the complexity of parts has been increased within the last decade due to the demands on ambitious designs and lightweight construction. As the forming processes are often laid out near the limit of feasibility, small variations of process parameters and materials' properties may lead to an increased scrap rate in serial production. The consideration of varying parameters in the computerized process design is generally realizable, but especially the modelling of the material properties' variation in numerical simulation close to reality is not investigated comprehensively yet. The varying parameters considered in a so called stochastic simulation are often limited to the mechanical properties, which can be determined within the uniaxial tensile test. As within the forming process of a complex sheet metal part different stress states occur, the batch variation under different forming conditions has to be investigated in detail. Within this work a basic investigation for the consideration of the batch variation under different stress states is presented. Three coils of the same steel grade, the mild deep drawing steel DX56, are characterised experimentally in order to investigate the scatter band of the stresses between the three batches representing material variation close to reality. For this the flow behaviour is determined under uniaxial stress condition and under biaxial stress condition. Furthermore the results of the tests under biaxial stress condition lead to a batch specific biax-stress-point, which represents a further reference point for the yield locus interpolation according to Hill 90. The forming limit diagrams are determined experimentally for the three batches in order to reproduce scattering of the onset of necking as well. Based on the experimental results, three batch specific material models for FE-simulation are prepared and used as input parameters for numerical forming simulations. Using the cross die geometry with two different initial blank geometries, different stress states can be adjusted in four reference points, covering the stress states between uniaxial and biaxial stress condition, thus, the plane strain area. Within the reference points, the effect of materials' properties variation on the risk of failure is evaluated.

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“…Material properties are some of the main inputs to such models. These vary not only from coil to coil, but also within the same coil (de Souza and Rolfe, 2010;Mukhopadhyay and Iqbal, 2005). Therefore, a detailed stochastic description of the material parameters is required for application in the optimization of forming processes.…”

Section: Chaptermentioning

confidence: 99%

“…Research on the material properties variation in metal forming processes generally ignores the effects of anisotropy (de Souza and Rolfe, 2010;Prates et al, 2018). It was shown by Gomes et al (2005) that anisotropy has a considerable effect on springback and therefore, for an accurate prediction, anisotropy cannot be ignored.…”

Section: The Complexity Of the Materials Modelmentioning

confidence: 99%

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Robust optimization and tailoring scatter of forming processes

Nejadseyfi¹

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ix malisatie methode word het op maat maken van spreiding genoemd. Een gradint-gebaseerde aanpak word gebruikt voor de analytische evaluatie van karakteristieken van de responsverdeling om het inverse probleem op te lossen. Omdat de evaluatie van een robuust optimum weinig rekenkracht vraagt dankzij de analytische beschrijving, is de inverse analyse ook efficint uit te voeren. Het op maat maken van spreiding bij het vormen van de B-stijl is met succes uitgevoerd op basis van de voorgestelde aanpak. Deze benadering resulteert in Pareto-grenzen die de optimale aanpassing van de tolerantie voor elke bron van ruis tonen, zodat aan de vereiste uitgangstolerantie wordt voldaan. Deze methode is succesvol toegepast voor het bepalen van de meest economische samenstelling van toleranties op alle bronnen van ruis, waarbij aan de vereiste nauwkeurigheid van het proces voldaan wordt. 3 Uncertainty evaluation based on analytical method 3.1 Calculation of the response mean and standard deviation 3.2 Analytical gradients of mean and standard deviation. .. 3.3 Iterative improvement of the metamodel. .. .. .. .. . 3.4 Evaluation of higher order statistical moments of the response. .

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Characterising material and process variation effects on springback robustness for a semi-cylindrical sheet metal forming process

Cited by 27 publications

References 19 publications

Obtaining manufactured geometries of deep-drawn components through a model updating procedure using geometric shape parameters

Obtaining manufactured geometries of deep-drawn components through a model updating procedure using geometric shape parameters

Variation of deep drawing steel grades’ properties in dependency of the stress state and its impact on FEA

Robust optimization and tailoring scatter of forming processes

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