Thomas Bieler | Michigan State University (original) (raw)

Papers by Thomas Bieler

Research paper thumbnail of Max Planck Institut crystal plasticty pillar compression simulation 07

Research paper thumbnail of Hydroforming of Large Grain Niobium Tube

17th International Conference on RF Superconductivity (SRF2015), Whistler, BC, Canada, Sept. 13-18, 2015, Dec 1, 2015

Currently most of Niobium (Nb) cavities are manufactured from fine grain Nb sheets. As-cast ingot... more Currently most of Niobium (Nb) cavities are manufactured from fine grain Nb sheets. As-cast ingots go through a series of steps including forging, milling, rolling, and intermediate annealing, before they are deep-drawn into a half-cell shape and subsequently electron beam welded to make a full cavity. Tube hydroforming, a manufacturing technique where a tube is deformed using a pressurized fluid, is an alternative to the current costly manufacturing process. A whole cavity can be made from a tube using tube hydroforming [1,2]. This study focuses on deformation of large grain Nb tubes during hydroforming. The crystal orientation of the grains is recorded. The tube is marked with a square-circlegrid which is used to measure the strain after deformation. The deformation of the tube is going to be modeled with crystal plasticity finite element [3–5] and compared with experiments. This paper only covers the characterization of the tube and the hydroforming process.

Research paper thumbnail of Metallurgical Fundamentals of Plastic Deformation

Research paper thumbnail of Crystal Plasticity Modeling of Single Crystal Nb

17th International Conference on RF Superconductivity (SRF2015), Whistler, BC, Canada, Sept. 13-18, 2015, Dec 1, 2015

Deformation behavior of niobium (Nb) is not thoroughly studied, although it is heavily used for s... more Deformation behavior of niobium (Nb) is not thoroughly studied, although it is heavily used for superconducting applications. This deficiency of knowledge makes use of fine grain sheets desirable because they are easier to deform uniformly than anisotropic large grain sheets. Simulation models for deformation of Nb are limited. Therefore, design of a new manufacturing procedure is costly because models predicting the deformation of Nb are inaccurate. Tensile tests were performed on single crystals with different orientations, to study the deformation behavior of Nb. Several crystal plasticity models were developed, calibrated and used to predict the deformation of single crystal tensile samples. This study compares the predictions of these models. As polycrystals are aggregates of single crystals, the model will also be useful for polycrystals.

Research paper thumbnail of The Crystal Plasticity Finite Element Method as a Multiphysics Framework

Wiley-VCH Verlag GmbH & Co. KGaA eBooks, Nov 8, 2010

Research paper thumbnail of Outlook and Conclusions

Research paper thumbnail of Numerical Aspects of Crystal Plasticity Finite Element Method Implementations

As far as the finite element method is concerned, crystal plasticity finite element (CPFE) approa... more As far as the finite element method is concerned, crystal plasticity finite element (CPFE) approaches can be regarded as a class of constitutive material models; therefore, they can be implemented directly into an finite element code when it is available in source form. In the case of commercial finite element codes, CPFE constitutive laws are implemented in the form of a user subroutine, for example, HYPELA2 in MSC. Marc (Mar, 2007) or UMAT/VUMAT in Abaqus (Aba, 2007). Depending on whether the finite element code is ...

Research paper thumbnail of A Slip Interaction Based Measure of Damage Nucleation in Grain Boundaries

Research paper thumbnail of Slip Interactions Leading to Damage Nucleation in TiAl Grain Boundaries

Research paper thumbnail of Dynamic Hardening Rule; a Generalization of the Classical Hardening Rule for Crystal Plasticity

Research paper thumbnail of Computational Crystal Plasticity

Research paper thumbnail of Crystal Plasticity Finite Element Modeling of Single Crystal Niobium Tensile Tests with Weighted Dynamic Hardening Rule

Springer eBooks, 2013

A new crystal plasticity model incorporating the mechanically induced martensitic transformation ... more A new crystal plasticity model incorporating the mechanically induced martensitic transformation in metastable austenitic steel has been formulated and implemented into the finite element analysis. The kinetics of martensite transformation is modeled by taking into consideration of a nucleation-controlled phenomenon, where each potential martensitic variant based on Kurdjumov-Sachs (KS) relationship has different nucleation probability as a function of the interaction energy between externally applied stress and lattice deformation. Therefore, the transformed volume fractions are determined following selective variants given by the crystallographic orientation of austenitic matrix and applied stress in the frame of the crystal plasticity finite element. The developed finite element program is capable of considering the effect of volume change by the Bain deformation and the lattice-invariant shear during the martensitic transformation by effectively modifying the evolution of plastic deformation gradient of the conventional rate-dependent crystal plasticity finite element. The validation of the proposed model has been carried out by comparing with the experimentally measured data under simple loading conditions. Good agreements with the measurements for the stress-strain responses, transformed martensitic volume fractions and the influence of strain rate on the deformation behavior will enable the model to be promising for the future applications to the real forming process of the TRIP aided steel.

Research paper thumbnail of Computational modeling of grain boundary microcrack nucleation using a slip interaction based definition of boundary character

Research paper thumbnail of Micro-mechanical modeling of near-gamma Ti-Al-Nb

A phenomenological crystal plasticity formulation for slip and twinning on the deformation system... more A phenomenological crystal plasticity formulation for slip and twinning on the deformation systems is used [Kalidindi1992] . Any imposed deformation of the material is partitioned into shear contributions from the individual deformation systems of the respective phases. Constitutive relations for both phases are implemented into a material subroutine for use with a finite element solver. Twinning deformation is implemented as a unidirectional slip system. The slip and twinning systems can be assigned different strengths and hardening behavior to account for various influences on critical resolved shear stress evolution.

Research paper thumbnail of Max Planck crystal plasticity FEM pillar compression single crystal size effect 01

Research paper thumbnail of Max Planck Institute crystal plasticity finite element simulation pillar compression 05

Research paper thumbnail of Identification of constitutive parameters by inverse simulation of indentation in single crystals and close to grain boundaries

Research paper thumbnail of Interconnection: The Joint

Fundamentals of Lead-Free Solder Interconnect Technology, 2014

The geometry of interconnections used in current electronic systems is described, and issues rela... more The geometry of interconnections used in current electronic systems is described, and issues related to the reflow process that melts and re-solidifies the solder to make the interconnection are introduced.

Research paper thumbnail of Chemical and Environmental Attack

Fundamentals of Lead-Free Solder Interconnect Technology, 2014

Expanding use of electronic systems in close proximity to biological systems, marine environments... more Expanding use of electronic systems in close proximity to biological systems, marine environments, and polluted air introduce elements that attack solder joints. Mechanisms that cause damage and their effects on the lifetime of electronic system are discussed.

Research paper thumbnail of Mechanical Stability and Performance

Fundamentals of Lead-Free Solder Interconnect Technology, 2014

In addition to thermal strains, other mechanical strains arising from handling (such as bending, ... more In addition to thermal strains, other mechanical strains arising from handling (such as bending, drop, or shock), and transport (vibration) add energy to joints that affects the rate and nature of microstructural evolution and damage generation.

Research paper thumbnail of Max Planck Institut crystal plasticty pillar compression simulation 07

Research paper thumbnail of Hydroforming of Large Grain Niobium Tube

17th International Conference on RF Superconductivity (SRF2015), Whistler, BC, Canada, Sept. 13-18, 2015, Dec 1, 2015

Currently most of Niobium (Nb) cavities are manufactured from fine grain Nb sheets. As-cast ingot... more Currently most of Niobium (Nb) cavities are manufactured from fine grain Nb sheets. As-cast ingots go through a series of steps including forging, milling, rolling, and intermediate annealing, before they are deep-drawn into a half-cell shape and subsequently electron beam welded to make a full cavity. Tube hydroforming, a manufacturing technique where a tube is deformed using a pressurized fluid, is an alternative to the current costly manufacturing process. A whole cavity can be made from a tube using tube hydroforming [1,2]. This study focuses on deformation of large grain Nb tubes during hydroforming. The crystal orientation of the grains is recorded. The tube is marked with a square-circlegrid which is used to measure the strain after deformation. The deformation of the tube is going to be modeled with crystal plasticity finite element [3–5] and compared with experiments. This paper only covers the characterization of the tube and the hydroforming process.

Research paper thumbnail of Metallurgical Fundamentals of Plastic Deformation

Research paper thumbnail of Crystal Plasticity Modeling of Single Crystal Nb

17th International Conference on RF Superconductivity (SRF2015), Whistler, BC, Canada, Sept. 13-18, 2015, Dec 1, 2015

Deformation behavior of niobium (Nb) is not thoroughly studied, although it is heavily used for s... more Deformation behavior of niobium (Nb) is not thoroughly studied, although it is heavily used for superconducting applications. This deficiency of knowledge makes use of fine grain sheets desirable because they are easier to deform uniformly than anisotropic large grain sheets. Simulation models for deformation of Nb are limited. Therefore, design of a new manufacturing procedure is costly because models predicting the deformation of Nb are inaccurate. Tensile tests were performed on single crystals with different orientations, to study the deformation behavior of Nb. Several crystal plasticity models were developed, calibrated and used to predict the deformation of single crystal tensile samples. This study compares the predictions of these models. As polycrystals are aggregates of single crystals, the model will also be useful for polycrystals.

Research paper thumbnail of The Crystal Plasticity Finite Element Method as a Multiphysics Framework

Wiley-VCH Verlag GmbH & Co. KGaA eBooks, Nov 8, 2010

Research paper thumbnail of Outlook and Conclusions

Research paper thumbnail of Numerical Aspects of Crystal Plasticity Finite Element Method Implementations

As far as the finite element method is concerned, crystal plasticity finite element (CPFE) approa... more As far as the finite element method is concerned, crystal plasticity finite element (CPFE) approaches can be regarded as a class of constitutive material models; therefore, they can be implemented directly into an finite element code when it is available in source form. In the case of commercial finite element codes, CPFE constitutive laws are implemented in the form of a user subroutine, for example, HYPELA2 in MSC. Marc (Mar, 2007) or UMAT/VUMAT in Abaqus (Aba, 2007). Depending on whether the finite element code is ...

Research paper thumbnail of A Slip Interaction Based Measure of Damage Nucleation in Grain Boundaries

Research paper thumbnail of Slip Interactions Leading to Damage Nucleation in TiAl Grain Boundaries

Research paper thumbnail of Dynamic Hardening Rule; a Generalization of the Classical Hardening Rule for Crystal Plasticity

Research paper thumbnail of Computational Crystal Plasticity

Research paper thumbnail of Crystal Plasticity Finite Element Modeling of Single Crystal Niobium Tensile Tests with Weighted Dynamic Hardening Rule

Springer eBooks, 2013

A new crystal plasticity model incorporating the mechanically induced martensitic transformation ... more A new crystal plasticity model incorporating the mechanically induced martensitic transformation in metastable austenitic steel has been formulated and implemented into the finite element analysis. The kinetics of martensite transformation is modeled by taking into consideration of a nucleation-controlled phenomenon, where each potential martensitic variant based on Kurdjumov-Sachs (KS) relationship has different nucleation probability as a function of the interaction energy between externally applied stress and lattice deformation. Therefore, the transformed volume fractions are determined following selective variants given by the crystallographic orientation of austenitic matrix and applied stress in the frame of the crystal plasticity finite element. The developed finite element program is capable of considering the effect of volume change by the Bain deformation and the lattice-invariant shear during the martensitic transformation by effectively modifying the evolution of plastic deformation gradient of the conventional rate-dependent crystal plasticity finite element. The validation of the proposed model has been carried out by comparing with the experimentally measured data under simple loading conditions. Good agreements with the measurements for the stress-strain responses, transformed martensitic volume fractions and the influence of strain rate on the deformation behavior will enable the model to be promising for the future applications to the real forming process of the TRIP aided steel.

Research paper thumbnail of Computational modeling of grain boundary microcrack nucleation using a slip interaction based definition of boundary character

Research paper thumbnail of Micro-mechanical modeling of near-gamma Ti-Al-Nb

A phenomenological crystal plasticity formulation for slip and twinning on the deformation system... more A phenomenological crystal plasticity formulation for slip and twinning on the deformation systems is used [Kalidindi1992] . Any imposed deformation of the material is partitioned into shear contributions from the individual deformation systems of the respective phases. Constitutive relations for both phases are implemented into a material subroutine for use with a finite element solver. Twinning deformation is implemented as a unidirectional slip system. The slip and twinning systems can be assigned different strengths and hardening behavior to account for various influences on critical resolved shear stress evolution.

Research paper thumbnail of Max Planck crystal plasticity FEM pillar compression single crystal size effect 01

Research paper thumbnail of Max Planck Institute crystal plasticity finite element simulation pillar compression 05

Research paper thumbnail of Identification of constitutive parameters by inverse simulation of indentation in single crystals and close to grain boundaries

Research paper thumbnail of Interconnection: The Joint

Fundamentals of Lead-Free Solder Interconnect Technology, 2014

The geometry of interconnections used in current electronic systems is described, and issues rela... more The geometry of interconnections used in current electronic systems is described, and issues related to the reflow process that melts and re-solidifies the solder to make the interconnection are introduced.

Research paper thumbnail of Chemical and Environmental Attack

Fundamentals of Lead-Free Solder Interconnect Technology, 2014

Expanding use of electronic systems in close proximity to biological systems, marine environments... more Expanding use of electronic systems in close proximity to biological systems, marine environments, and polluted air introduce elements that attack solder joints. Mechanisms that cause damage and their effects on the lifetime of electronic system are discussed.

Research paper thumbnail of Mechanical Stability and Performance

Fundamentals of Lead-Free Solder Interconnect Technology, 2014

In addition to thermal strains, other mechanical strains arising from handling (such as bending, ... more In addition to thermal strains, other mechanical strains arising from handling (such as bending, drop, or shock), and transport (vibration) add energy to joints that affects the rate and nature of microstructural evolution and damage generation.