On the micro- and macroscopic elastoplastic deformation behaviour of cast iron when subjected to cyclic loading

Norman, Viktor; Calmunger, Mattias

doi:10.1016/j.ijplas.2018.11.019

Cited by 20 publications

(28 citation statements)

References 49 publications

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“…Consistently, both the FEM calculations and the DIC observations showed a pronounced increase in strain levels at the graphite particle boundaries. Therefore, the results of Reference [7] confirmed that graphite particles can be considered as internal notches, as also argued in the current work.…”

Section: Of 21supporting

confidence: 89%

“…The mechanical graphite/matrix interaction of CGI is demonstrated by Ghodrat and Kestens [6], showing a weak mechanical bonding. This was confirmed by a recent work [7], studying the mechanical behavior of the graphite/matrix interface for cycling load conditions at room temperature, for three types of cast iron, including spheroidal cast iron. The measured macroscopic cyclic stress-strain behavior was validated using both micromechanical calculations with the finite element method (FEM) and microstructural strain measurements by digital image correlation (DIC).…”

Section: Of 21supporting

confidence: 74%

“…For the local strain model, TMF lifetimes are calculated numerically in a similar manner as described for the local stress-based model. Assuming specific values for the model parameters B, A, K ε , and m, the number of cycles is calculated for the first 0.001 mm of crack extension around the entire circumference of the specimen (see Equations (7) and (11)). This process is repeated for subsequent steps of 0.001 mm, adjusting the values of ∆ε pl sharp in each step in accordance with the increased crack length (the value of ∆ε pl blunt is constant).…”

Section: Calculating Tmf Lifetime By Numerical Integration (Local Strmentioning

confidence: 99%

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Thermo-Mechanical Fatigue Lifetime Assessment of Spheroidal Cast Iron at Different Thermal Constraint Levels

Ghodrat

Kalra

Kestens

et al. 2019

Metals

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In previous work on the thermo-mechanical fatigue (TMF) of compacted graphite iron (CGI), lifetimes measured under total constraint were confirmed analytically by numerical integration of Paris’ crack-growth law. In current work, the results for CGI are further validated for spheroidal cast iron (SGI), while TMF tests at different constraint levels were additionally performed. The Paris crack-growth law is found to require a different CParis parameter value per distinct constraint level, indicating that Paris’ law does not capture all physical backgrounds of TMF crack growth, such as the effect of constraint level. An adapted version of Paris’ law is developed, designated as the local strain model. The new model considers cyclic plastic strains at the crack tip to control crack growth and is found to predict TMF lifetimes of SGI very well for all constraint levels with a single set of parameters. This includes not only full constraint but also over and partial constraint conditions, as encountered in diesel engine service conditions. The local strain model considers the crack tip to experience a distinct sharpening and blunting stage during each TMF cycle, with separate contributions to crack-tip plasticity, originating from cyclic bulk stresses in the sharpening stage and cyclic plastic bulk strains in the blunting stage.

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Section: Of 21supporting

confidence: 89%

Section: Of 21supporting

confidence: 74%

Section: Calculating Tmf Lifetime By Numerical Integration (Local Strmentioning

confidence: 99%

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Thermo-Mechanical Fatigue Lifetime Assessment of Spheroidal Cast Iron at Different Thermal Constraint Levels

Ghodrat

Kalra

Kestens

et al. 2019

Metals

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“…When regarding the type of load, important characteristics of the complicated constitutive behaviour of grey cast iron can be found in the simulation results. This includes the nonexistence of a linear elastic regime under tensile load and the tension- compression-stress asymmetry [43]. Figure 12 clearly depicts the asymmetric behaviour under tensile and compressive load, which is typical for cast iron with lamellar graphite on the macroscopic scale [44,45].…”

Section: Multiphase Simulations In An Idealised Grey Cast Iron Microstructurementioning

confidence: 94%

Phase-Field Model for the Simulation of Brittle-Anisotropic and Ductile Crack Propagation in Composite Materials

Herrmann

Schneider

Schoof

et al. 2021

Preprint

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In this work, a small-strain phase-field model is presented, which is able to predict crack propagation in systems with anisotropic brittle and ductile constituents. To model the anisotropic brittle crack propagation, an anisotropic critical energy release rate is used. The brittle constituents behave linear-elastically, in a transversely isotropic manner. Ductile crack growth is realised by a special crack degradation function, depending on the accumulated plastic strain, which is calculated by following the J2-plasticity theory. The mechanical jump conditions are applied in solid-solid phase transition regions. The influence of the relevant model parameters on a crack, propagating through a planar brittle-ductile interface, and furthermore a crack developing in a domain with a single anisotropic brittle ellipsoid, embedded in a ductile matrix, is investigated. We demonstrate that important properties, concerning the mechanical behaviour of grey cast iron, such as the favoured growth of cracks along the graphite lamellae and the tension-compression load asymmetry of the stress-strain response, are covered by the model. The behaviour is analysed on basis of a simulation domain consisting of three differently oriented elliptical inclusions, embedded in a ductile matrix, which is subjected to tensile and compressive load. The used material parameters correspond to graphite lamellae and pearlite.

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“…As an overview of the most important literature, dealing with a similar problem 70 as the publication, the following articles should be mentioned: Bonora and Ruggiero [3], Velichko et al [5], Pina et al [6], Norman and Calmunger [13], Metzger and Seifert [16], Pina et al [18]. Bonora and Ruggiero [3] addresses the micromechanical behaviour of ferritic cast iron with spheroidal graphite.…”

Section: Introduction 15mentioning

confidence: 99%

Computational Determination of Macroscopic Mechanical and Thermal Material Properties for Different Microstructural Variants of Cast Iron

Herrmann¹,

Schmid²,

Schneider³

et al. 2021

Preprint

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The sensitivity of macroscopic mechanical and thermal properties of grey cast iron is computationally investigated for a variety of graphite microstructures over a wide temperature range. In order to represent common graphite microstructures according to DIN EN ISO 945-1, a synthetic approach is used to algorithmically generate simulation domains. The developed mechanical and thermal model is applied in a large simulation study. The study includes statistical volume elements of the graphite microstructures classes GG-15 and IA2 to IA5, with 10 v.-%, 11 v.-% and 12 v.-% graphite, respectively, for a temperature range from 20 °C to 750 °C. Homogenized macroscopic quantities such as the Young's moduli, Poisson's ratios, yield strengths and thermal conductivities are predicted for the different microstructure classes by applying simulation and data analysis tools of the research data infrastructure Kadi4Mat.

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On the micro- and macroscopic elastoplastic deformation behaviour of cast iron when subjected to cyclic loading

Cited by 20 publications

References 49 publications

Thermo-Mechanical Fatigue Lifetime Assessment of Spheroidal Cast Iron at Different Thermal Constraint Levels

Thermo-Mechanical Fatigue Lifetime Assessment of Spheroidal Cast Iron at Different Thermal Constraint Levels

Phase-Field Model for the Simulation of Brittle-Anisotropic and Ductile Crack Propagation in Composite Materials

Computational Determination of Macroscopic Mechanical and Thermal Material Properties for Different Microstructural Variants of Cast Iron

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