Model Identification and FE Simulations: Effect of Different Yield Loci and Hardening Laws in Sheet Forming

Flores, Paulo; Duchêne, Laurent; Lelotte, Thomas; Bouffioux, C; Houdaigui, F. El; Bael, Albert Van; He, S.; Duflou, Joost R.; Habraken, Anne Marie

doi:10.1063/1.2011248

Cited by 19 publications

(24 citation statements)

References 3 publications

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“…It must be noted that during SPIF the strain history is not proportional because of successive bending and unbending around the tool. Cyclic loading, generated by serrated strain paths, has been widely observed in FE simulations within the ISF literature (Flores et al, 2007;Eyckens et al, 2007;Seong et al, 2014) but also experimentally through digital image correlation (DIC) measurements (Eyckens et al, 2010). This cyclic effect can have a great influence on formability, as demonstrated by Eyckens et al (2007).…”

Section: Bendingmentioning

confidence: 99%

Damage prediction in single point incremental forming using an extended Gurson model

Guzmán

Yuan

Duchêne

et al. 2018

International Journal of Solids and Structures

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Single point incremental forming (SPIF) has several advantages over traditional forming, such as the high formability attainable by the material. Different hypotheses have been proposed to explain this behavior, but there is still no straightforward relation between the particular stress and strain state induced by SPIF and the material degradation leading to localization and fracture. A systematic review of the state of the art about formability and damage in SPIF is presented and an extended Gurson-TvergaardNeedleman (GTN) model was applied to predict damage in SPIF through finite element (FE) simulations. The line test was used to validate the simulations by comparing force and shape predictions with experimental results. To analyze the failure prediction, several simulations of SPIF cones at different wall angles were performed. It is concluded that the GTN model underestimates the failure angle on SPIF due to wrong coalescence modeling. A physically-based Thomason coalescence criterion was then used leading to an improvement on the results by delaying the onset of coalescence.

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Section: Bendingmentioning

confidence: 99%

Damage prediction in single point incremental forming using an extended Gurson model

Guzmán

Yuan

Duchêne

et al. 2018

International Journal of Solids and Structures

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“…In order to quantify the effect of the strain path change, Schmitt et al [12] proposed a single parameter defined as the cosine of the angle in the strain space between the strain rate tensors during the pre-strain and the subsequent strain path. Studies of Bouvier et al [13], Haddag et al [14,15] and Flores et al [16] have dealt with the influence of such a complex constitutive equation on the prediction of several forming process parameters at room temperature, when compared to a mixed hardening.…”

Section: Introductionmentioning

confidence: 99%

Examination of the Strength and Ductility of AA-1050 Material Shaped with the MUlti-Stage Deep Drawing Method

Karali¹

2011

Archives of Metallurgy and Materials

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Deep drawing materials are easily shapeable materials, because of their high ductility. Aluminum alloy materials are classified in the deep drawing materials group because they are easily shapeable. In order to increase the strength, materials are made an alloy by adding some chemical additives. They are also provided strength increasing by tempering. Normally, materials harden when reshaped under plastic deformation. Reshape the shaped materials harden while reducing its ductility. In this study, changes in mechanical properties immediately after the AA-1050 (T0) sheet material is shaped by the multi-stage deep drawing method and after storage were investigated. It was calculated that a 4-stage shaping is needed for a tube production at selected sizes. Deep drawing treatments are made in sizes of these stages. Samples were collected from each cold-shaped intermediary form. Mechanical properties of this materials are determined by applying tensile test. Some basic parameters, like tensile stresses, max. uniform strain rates, strain hardenings and strength coefficients, are investigated and compared. Obtained data were explained using graphs. It was observed that tensile strength increased and strain quantities were reduced at every stage. It is also seen an increase in strain hardening index.Keywords: Al-1050, sheet metal forming, multi-stage deep drawing Stopy do głębokiego tłoczenia są materiałami łatwo odkształcalnymi z powodu ich wysokiej plastyczności. Stopy aluminium należą do grupy materiałów odpowiednich do wytłaczania, ponieważ są łatwo odkształcalne. W celu zwiększenia wytrzymałości, do aluminium dodawane są pewne dodatki stopowe. Wytrzymałość wzrasta także po odpuszczaniu. Zwykle, materiały umacniają się wskutek deformacji plastycznej, co wiąże się ze zmniejszeniem plastyczności. W tej pracy, badano zmiany właściwości mechanicznych stopu AA-1050 (T0) bezpośrednio po odkształceniu przez wielokrotne głębokie tłoczenie oraz po okresie przechowywania. Obliczono, że do produkcji rur w wybranych rozmiarach potrzebne jest 4-etapowe odkształce-nie. Próbki do badań pobrane były po każdym etapie odkształcenia na zimno. Właściwości mechaniczne tych materiałów zostały zbadane przez zastosowanie próby rozciągania. Niektóre podstawowe parametry, takie jak naprężenie rozciągające, maksymalna jednorodna prędkość odkształcenia, umocnienie po odkształceniu i współczynniki siły, zostały zbadane i porównane. Uzyskane dane zostały przedstawione za pomocą wykresów. Stwierdzono, że wytrzymałość na rozciąganie wzrasta a stopień odkształcenia maleje po każdym etapie odkształcenia. Obserwowano także wzrost wskaźnika umocnienia odkształcenia.

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“…Regarding the use of material models, Flores et al [70] showed that the use of an anisotropic yield criterion is not a key factor in terms of the geometric prediction of a cone wall. Also, Ambrogio et al [77] presented that the sheet material orientation has no substantial effect on the predicted straining history with an anisotropic material constitutive law.…”

Section: Finite Element Modellingmentioning

confidence: 99%

“…The partial models -24-were compared to the full models in [70], showing that although the side wall was reproduced well with partial models, significant deviations were observed in the undeformed zone of the sheet. Also, it was suggested that a detailed description of the behaviour occurring across the thickness of the metal sheet is crucial for an accurate force prediction.…”

Section: Finite Element Modellingmentioning

confidence: 99%

“…It was found that the finite element model with shell elements is not suitable for all tool path strategies to capture the transverse shear behaviour of the sheet. Further work with FE models using elements able to properly reveal the shear components was suggested.Regarding the use of material models, Flores et al [70] showed that the use of an anisotropic yield criterion is not a key factor in terms of the geometric prediction of a cone wall. Also, Ambrogio et al [77] presented that the sheet material orientation has no substantial effect on the predicted straining history with an anisotropic material constitutive law.…”

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confidence: 99%

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Forming force prediction and process investigation for incremental sheet forming

Li¹

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Incremental sheet forming (ISF) is a promising manufacturing process in which flat metal sheets are gradually formed into 3D shapes using a generic forming tool. Since the process features benefits of reduced forming forces, enhanced formability and greater process flexibility, it has a great potential to achieve economic payoff for rapid prototyping applications and for small quantity production in various applications. Although substantial research has been performed in the past decades on ISF, there is still a lack of an efficient prediction of forming force to facilitate the production design and optimization of the process. Also, unsatisfactory part quality obtained still hampers its wide use in industrial applications. Therefore, the work presented in this thesis is mainly focused on two aspects of ISF: efficient forming force prediction and process investigation and its improvement.The first research aspect of this thesis has been focused on the development of an efficient force prediction model that includes the development of both finite element (FE) and analytical models. (i) FE modelling. Two types of FE models have been established using an explicit code LS-DYNA to investigate the deformation mechanism in ISF which is the basis for developing the force prediction model as well as further improving the forming process. First, FE models with shell elements for the groove forming process were set up and the strain behaviour and thickness distribution with different tools were evaluated and compared with experimental results. The strain behaviour of elements at different positions has been studied and the maximum strain has been found near the end of the groove corresponding to the failure location. The thickness distributions of the groove formed with different sized tools were predicted and it was found that the groove formed by the 20 mm tool is thinner than that formed by the 30 mm tool. Second, to further investigate different deformation modes and their evolution history in ISF, a FE model with fine solid elements for the cone-forming process has been established. The FE model was verified by experimental work with forming forces to allow a quantitative study of deformation behaviours of stretching, bending and shearing during the process. The evolution history of all the strain components along with the effective strain was presented. Moreover, the characteristic of each strain component and its contribution to the total effective plastic strain during the cone-forming process were investigated in detail. It was confirmed from FE simulations that the deformation mechanism in the ISF process is a combination of shearing, bending and stretching though the quantitative contributions in two directions are varied. (ii) Force prediction modelling and its validation. Based on the understanding of the deformation mechanism during the forming process, an efficient analytical model for tangential force prediction has been developed. Initially, deformation modes including shear, bending and stretchin...

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Model Identification and FE Simulations: Effect of Different Yield Loci and Hardening Laws in Sheet Forming

Abstract: The bi-axial experimental equipment [Flores, P., Rondia, E., Habraken, A.M., 2005a

Cited by 19 publications

References 3 publications

Damage prediction in single point incremental forming using an extended Gurson model

Damage prediction in single point incremental forming using an extended Gurson model

Examination of the Strength and Ductility of AA-1050 Material Shaped with the MUlti-Stage Deep Drawing Method

Forming force prediction and process investigation for incremental sheet forming

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