Microstructural strain distribution in ductile iron; comparison between finite element simulation and digital image correlation measurements

• This paper presents a study on microstructural deformation of a ferritic-pearlitic ductile iron, utilizing in-situ tensile testing, digital image correlation (DIC) and finite element analysis (FEA). For this purpose, the in-situ tensile test and DIC were used to measure local strain fields in the deformed microstructure. Furthermore, a continuum finite element (FE) model was used to predict the strain maps in the microstructure. Ferrite and pearlite parameters for the FE-model were optimized based on the Ramberg-Osgood relation. The DIC and simulation strain maps were compared qualitatively and quantitatively. Similar strain patterns containing shear bands in identical locations were observed in both strain maps. The average and localized strain values of the DIC and simulation conformed to a large extent. It was found that the Ramberg-Osgood model can be used to capture the main trends of strain localization. The discrepancies between the simulated and DIC results were explained based on the; (i) subsurface effect of the microstructure; (ii) differences in the strain spatial resolutions of the DIC and simulation and (iii) abrupt changes in strain prediction of the continuum FE-model in the interface of the phases due to the sudden changes in the elastic modulus. © 2015 Elsevier B.V.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

Digital image correlation (DIC)

Ductile iron

Finite elements analysis (FEA)

In-situ tensile test

Microstructural deformation

Deformation

Ductility

Ferrite

Ferritic steel

Image analysis

Iron

Microstructure

Nodular iron

Pearlite

Strain measurement

Tensile testing

D. digital image correlation (DIC)

Deformed microstructure

Digital image correlations

Finite element simulations

Finite elements analysis

Microstructural strains

Finite element method

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