Influence of the plastic properties of a material on the forming limit diagram for sheet metal in tension

Marciniak, Z.; Kuczyński, K.; Pokora, Tadeusz

doi:10.1016/0020-7403(73)90068-4

Cited by 419 publications

(127 citation statements)

References 2 publications

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“…The yield stress was defined by the 0.2% plastic-strain offset method. Also, the true stress (σ) -plastic strain (ε p ) data along the rolling direction was fitted to the modified Swift power law in which the strain-rate effect is considered as 19 :…”

Section: Uniaxial Tensile Testingmentioning

confidence: 99%

“…Nowadays, there is a trend towards determining the FLC by using a single equipment with samples of different widths. This can be achieved with the Nakazima 28 and the Marciniak 19 tests, where the blank sheet is fixed at its periphery, and deformed by a punch, the shape of which is either spherical (Nakazima) or cylindrical flat-bottomed (Marciniak). The Marciniak test was adopted in this study to obtain the FLC of the hot-dip galvanized IF steel sheet.…”

Section: Marciniak Punch Testmentioning

confidence: 99%

“…The minimum limit strain for the r 45 > 1,0 case is obtained for Ψ ≅ 45 degrees whereas ther 45 < 1.0 material has minima coincident with isotropic reference case for Ψ = 0 and 90 degrees. As pointed out by Barata da Rocha et al 38 , the original assumption of normality of the geometrical imperfection with respect to major in-plane principal stress 19 is too restrictive since it would provide a unique limit strain in the equibiaxial stretching condition independently of the r 45 value. Figure 14 compares the theoretical predictions for an isotropic (von Mises) material determined from linear strain-paths and bi-linear strain-paths after a pre-straining level of 15% under uniaxial tension (UT), plane-strain tension (PS) and equibiaxial straining (ES) conditions, respectively.…”

Section: Limit Strains and Surface Roughnessmentioning

confidence: 99%

“…Its initial interpretation in terms of variations in sheet thickness (geometric imperfection) was amended by considering also possible variations in the strength of the material (material or metallurgical imperfection). This idea was already mentioned in the work of Marciniak et al 19 , and it was later materialized by assuming spatial variations in the orientation distribution of grains, giving variations in the Taylor factor 20 . Inhomogeneous damage due to the nucleation and growth of microvoids can also occur, for instance by decohesion between matrix and inclusion, or by fragmentation of inclusions, leading to a decrease in the surface area transmitting the load 21 .…”

Section: Introductionmentioning

confidence: 99%

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Experimental analysis and theoretical predictions of the limit strains of a hot-dip galvanized interstitial-free steel sheet

2013

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In this work, the formability of a hot-dip galvanized interstitial-free (IF) steel sheet was evaluated by means of uniaxial tensile and Forming Limit Curve (FLC) tests. The FLC was defined using the flat-bottomed Marciniak's punch technique, where the strain analysis was made using a digital image correlation software. A plastic localization model was also proposed wherein the governing equations are solved with the help of the Newton's method. The investigated hot-dip galvanized IF steel sheet presented a very good formability level in the deep-drawing range consistent with the measured Lankford values. The predicted limit strains were found to be in good agreement with the experimental data of the hot-dip galvanized IF steel sheet owing to the definition of the localization model geometrical imperfection as a function of the experimental surface roughness evolution and, in particular, to the yield surface flattening near to the plane-strain stress state authorized by the adopted yield criterion.

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Section: Uniaxial Tensile Testingmentioning

confidence: 99%

Section: Marciniak Punch Testmentioning

confidence: 99%

Section: Limit Strains and Surface Roughnessmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental analysis and theoretical predictions of the limit strains of a hot-dip galvanized interstitial-free steel sheet

2013

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“…Estos modelos intentaron describir el fenómeno de la localización de la deformación en el conformado de materiales bajo distintos modos de carga, asumiendo la presencia de una imperfección inicial, geomé-trica o de deformación y midiendo su crecimiento relativo al resto de la pieza conformada, para conseguir un equilibrio en las dos regiones. De esta manera, el grado exacto de la localización de la fluencia, conocido como el límite de conformado, ha podido ser evaluado [24][25][26][27][28][29] .…”

Section: Criterios Fenomenológicos Mecánicosunclassified

Criterios de predicción de inestabilidades plásticas en procesos de conformado en caliente. (Parte I: Revisión teórica)

Omar¹,

Prado²

2010

REVMETAL

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ResumenLos procesos de conformado de materiales inducen frecuentemente altos grados de deformación, a grandes velocidades de deformación, e imponen modos de solicitación multiaxiales y muy complejos. Dichos procesos quedan esencialmente limitados por la aparición y desarrollo de inestabilidades plásticas. Éstas pueden ser la causa directa de la propagación rápida de una fisura, que puede dar lugar a una rotura final. La complejidad de los modos de deformación y la intervención simultanea de varios parámetros han llevado a varios investigadores a desarrollar diversos criterios, con diferentes planteamientos, para predecir la aparición de defectos y optimizar los parámetros de control en los procesos de conformado. El presente trabajo pretende exponer, a modo de revisión, algunos criterios ampliamente usados en la literatura para la predicción de las inestabilidades plásticas durante el conformado de materiales. Se ha estimado oportuno dividir la materia del trabajo en dos partes: una primera parte presenta los criterios fenomenológi-cos de predicción de las inestabilidades plásticas, basados en la observación descriptiva de los fenómenos microscó-picos de la deformación (endurecimiento por deformación y sensibilidad a la velocidad de deformación), luego se analizan los criterios continuos basados en los principios de máxima velocidad de producción de entropía de la termodinámica irreversible aplicada a la mecánica continua de la fluencia plástica en grandes deformaciones. Asimismo, se comenta una discusión bibliográfica entablada entre varios autores referida al fundamento físico del Modelo Dinámico de Materiales. En la segunda parte, se lleva a cabo un estudio comparativo para caracterizar la inestabilidad plástica durante un proceso de conformado en caliente de un acero microaleado de medio carbono usando criterios continuos y fenomenológicos. Palabras claveConformado en caliente; Criterios de Inestabilidades plásticas; Modelo dinámico de materiales; Localización de la fluencia. Criteria for prediction of plastic instabilities for hot working processes. (Part I: Theoretical review) AbstractHot working processes often induce high levels of deformation at high strain rates, and impose very complex multiaxial modes of solicitation. These processes are essentially limited by apparition and development of plastic instabilities. These may be the direct cause of rapid crack propagation, which lead to a possible final rupture. The complexity of deformation modes and the simultaneous intervention of several parameters have led many researchers to develop various criteria, with different approaches, to predict the occurrence of defects and to optimize process control parameters. The aim of the present paper is to summarize the general characteristics of some instability criteria, widely used in the literature, for the prediction of plastic instabilities during hot working. It was considered appropriate to divide the work into two parts: part I presents the phenomenological criteria for the prediction of plastic instabili...

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Steel Processing: Formability of Steel Sheets and Tailor‐Welded Blanks for Automotive Applications

Bandyopadhyay

Panda

2014

Encyclopedia of Automotive Engineering

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In recent decades, great improvements have been made in the production of steel sheets with high formability. Automotive companies are using various grades of steels to meet the customers' ever‐changing demands for low cost and fuel efficient vehicles. Applications of advanced high strength steel and tailored blank technology in stamping of various components are a major boost for steel manufacturers, and hence, steel sheets remain the fair choice for automotive body part fabrication as compared to aluminum and magnesium sheets. In this chapter, various sheet metal‐forming processes and formability diagnostic measures such as limiting drawing ratio, limiting dome height, forming limit diagram were discussed with respect to constitutive properties of the sheet metal, damage model, and design modifications in toolings and blank shape. Emphasis is placed on application of finite element method‐based CAE (computer‐aided engineering) techniques to predict forming behavior of various steel sheets and tailor‐welded blanks while selecting the right materials for stamping the automotive body components.

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Influence of the plastic properties of a material on the forming limit diagram for sheet metal in tension

Cited by 419 publications

References 2 publications

Experimental analysis and theoretical predictions of the limit strains of a hot-dip galvanized interstitial-free steel sheet

Experimental analysis and theoretical predictions of the limit strains of a hot-dip galvanized interstitial-free steel sheet

Criterios de predicción de inestabilidades plásticas en procesos de conformado en caliente. (Parte I: Revisión teórica)

Steel Processing: Formability of Steel Sheets and Tailor‐Welded Blanks for Automotive Applications

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