A void–crack nucleation model for ductile metals

Horstemeyer, Mark F.; Gokhale, A.M.

doi:10.1016/s0020-7683(98)00239-x

Cited by 190 publications

(86 citation statements)

References 66 publications

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“…By inhibiting any of these three stages, the ductility and strength of these alloys can be improved. The process of void nucleation is fairly well understood by both experiment and theory [37][38][39][40][41]. Void nucleation usually occurs at second phase precipitates or inclusions.…”

Section: (A) Microdamage Evolution In Ductile Fracturementioning

confidence: 99%

Computational aspects of steel fracturing pertinent to naval requirements

Matic

Geltmacher

Rath

2015

Phil. Trans. R. Soc. A.

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Modern high strength and ductile steels are a key element of US Navy ship structural technology. The development of these alloys spurred the development of modern structural integrity analysis methods over the past 70 years. Strength and ductility provided the designers and builders of navy surface ships and submarines with the opportunity to reduce ship structural weight, increase hull stiffness, increase damage resistance, improve construction practices and reduce maintenance costs. This paper reviews how analytical and computational tools, driving simulation methods and experimental techniques, were developed to provide ongoing insights into the material, damage and fracture characteristics of these alloys. The need to understand alloy fracture mechanics provided unique motivations to measure and model performance from structural to microstructural scales. This was done while accounting for the highly nonlinear behaviours of both materials and underlying fracture processes. Theoretical methods, data acquisition strategies, computational simulation and scientific imaging were applied to increasingly smaller scales and complex materials phenomena under deformation. Knowledge gained about fracture resistance was used to meet minimum fracture initiation, crack growth and crack arrest characteristics as part of overall structural integrity considerations.

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Section: (A) Microdamage Evolution In Ductile Fracturementioning

confidence: 99%

Computational aspects of steel fracturing pertinent to naval requirements

Matic

Geltmacher

Rath

2015

Phil. Trans. R. Soc. A.

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“…Schematic of the fictitious material with increasing nucleation density and void growth of a model framework The void nucleation rule follows the work done by Horstemeyer and Gohkale (1999) and is employed to capture the effect of voids nucleating under tension, compression, and torsion. The void nucleation function in the integrated form is given by, where coeff C is a material constant, T is temperature, ) (t ε is the strain rate, and T C η is a temperature dependent material constant.…”

Section: Damage Model Formulationmentioning

confidence: 99%

“…The internal state variable (ISV) plasticity-damage model presented by Bammann and Aifantis (1989) and Bammann et al (1996) and later modified to account for nucleation, growth, and coalescence by Horstemeyer and Gohkale (1999) and Horstemeyer et al, (2000) has been used to predict the plastic deformation of many types of metals under various loading conditions (cf. Horstemeyer, 2001).…”

Section: Introductionmentioning

confidence: 99%

Damage and stress state influence on the Bauschinger effect in aluminum alloys

Jordon

Horstemeyer

Solanki

et al. 2007

Mechanics of Materials

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In this work, the Bauschinger effect is shown to be intimately tied not only to plasticity but to damage as well. The plasticity-damage effect on the Bauschinger effect is demonstrated by employing different definitions (Bauschinger Stress Parameter, Bauschinger Effect Parameter, the Ratio of Forward-to-Reverse Yield, and the Ratio of Kinematic-to-Isotropic Hardening) for two differently processed aluminum alloys (rolled and cast) in which specimens were tested to different prestrain levels under tension and compression. Damage progression from second phase particles and inclusions that were generally equiaxed for the cast A356-T6 aluminum alloy and elongated for the rolled 7075 aluminum alloy was quantified from interrupted experiments. Observations showed that the Bauschinger effect had larger values for compression prestrains when compared to tension. The Bauschinger effect was also found to be a function of damage to particles/inclusions, dislocation/particle interaction, the work hardening rate, and the Bauschinger effect definition. ii ACKNOWLEDGMENTS

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“…(a) increasing void growth (b) increasing nucleation sites The void nucleation rule of Horstemeyer and Gokhale (1998) T is temperature in the absolute scale, and C Tη is the temperature dependent material constant determined from experiments ( Figure 3.19). The material parameters a, b, and c relate to the volume fraction of nucleation events arising from local microstresses in the material.…”

Section: -6mentioning

confidence: 99%

From Atoms to Autos - A new Design Paradigm Using Microstructure-Property Modeling Part 1: Monotonic Loading Conditions

Horstemeyer¹

2001

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A multiscale analysis was performed to develop a macroscale microstructure-mechanical property model that includes several types of microstructural inclusions found in an A356-T6 cast aluminum alloy for use in automotive chassis component design. This microstructureproperty model can be used for finite element analysis in which the deformation history, temperature dependence, and strain rate dependence vary. To capture the history effects from the boundary conditions and load histories, the microstructural defects and progression of damage from these defects and microstructural features such as casting porosity, silicon particles, and intermetallics must be reflected in the model. Internal state variables are used in the material model to reflect void/crack nucleation, void growth, and void coalescence from the casting microstructural features under different temperatures, strain rates, and deformation paths. Furthermore, internal state variables are used to reflect the dislocation density evolution that affects the work hardening rate and thus stress state under different temperatures and strain rates. In order to determine the pertinent effects of the microstructural features, several different length scale analyses were performed. Once the pertinent microstructural features were determined and included in the microstructure-mechanical property model, tests were performed on a control arm to validate its precision. Very encouraging results were demonstrated when using the model for optimizing structural components in a predictive fashion. EXECUTIVE SUMMARYIn designing a structural component, a failure analysis will typically include a finite element analysis and microstructural evalutation. Sometimes the microstructural evalution will quantify the inclusion content (source of damage in a component) in a prioritized fashion differently than the finite element analysis. Let us consider the hypothetical situation exemplified in Figure 1.Here we have an automotive control arm that shows that has undergone certain boundary conditions in a finite element analysis. The finite element analysis revealed that the highest Mises stress occurred at point D. For the different regions of interest, microstructural analysis using optical imaging revealed the largest defect occurred at point B. Both camps would argue about the location of final failure. However, in our hypothetical example, both are wrong, because the final failure state is both a function of the initial inclusion state and boundary conditions. As such, point A failed first. The key is the development of the microstructureproperty model that can be included in a finite element analysis, which includes the inclusion content (or the sources of damage progression). IIIn order to accomplish such a task, a multiscale analysis was performed with a focus on a macroscale microstructure-mechanical property model that includes several types of microstructural inclusions found in an A356-T6 cast aluminum alloy for use in automotive chassis component design. This...

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A void–crack nucleation model for ductile metals

Cited by 190 publications

References 66 publications

Computational aspects of steel fracturing pertinent to naval requirements

Computational aspects of steel fracturing pertinent to naval requirements

Damage and stress state influence on the Bauschinger effect in aluminum alloys

From Atoms to Autos - A new Design Paradigm Using Microstructure-Property Modeling Part 1: Monotonic Loading Conditions

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