Bio:
Myoung-Gyu Lee
last updated September 21, 2007
EDUCATION
Ph. D in Materials
Science and Engineering, January 2004
M.S. in Fiber and
Polymer Science, January 1999
B.S. in Fiber and Polymer Science, January 1997
Qualifications
l
Continuum
mechanics: Strength
of materials, Metal plasticity, elasticity, visco-elasticity, continuum based
crystal plasticity, anisotropic yield function, non-linear cyclic hardening
l
Materials: Magnesium alloys, Advanced High
Strength Steel (AHSS), Dual-phase steel, Aluminum alloys, Polymer composites,
Thin glass, Electrical materials such as Tantalum, TRansformation Induced
Plasticity (TRIP)
l
Micro
structure: Theory of Dislocation, deformation
texture, strengthening mechanism
l
Advanced
FEA modeling: Press
hardening (Hot stamping), nonlinear structural, dynamic stress, crystal
plasticity, meso-scale simulation, crashworthiness, forming, springback,
residual stress, contact problems, heat transfer, handling of user subroutine
of commercial FE software
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CAE, solid modeling: ABAQUS, ANSYS, Dyna-3D, Pam-Stamp,
Hyper-mesh, Patran, I-deas
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Programming
languages: Fortran
77/90, C/C++, Html, Matlab, Mathematica
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Mechanical/material
characterization:
Tensile/compressive, cyclic tests, impact test, forming/springback tests,
bending/torsion tests, Microscopes, X-ray, OIM
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Communication
skills: proposal,
report, paper writing; public presentations; work coordination
PROFESSIONAL
ORGANIZATIONS, SERVICES
The Minerals, Metals
and Materials Society (TMS)
Editorial board of
Korean Society for Technology of Plasticity
Reviewer of
International Journal of Plasticity
Reviewer of
International Journal of Solids and Structures
Reviewer of Transactions
of Materials Processing (Korean)
EXPERIENCE
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Senior Researcher, Korea Institute of Machinery &
Materials,
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Post-doctoral Researcher, Supervisor: Prof. Robert H.
Wagoner, The
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Post-doctoral Researcher, Supervisor: Prof. Peter M. Anderson,
The
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Post-doctoral Research Fellow, Supported by the BK21 (Brain
l
Graduate Research Assistant (Ph.D), School of Materials Science and
Engineering, Seoul National University, Seoul, Korea, March 1999~Feb. 2004
l
Graduate Research Assistant (MS), Department of Fiber and Polymer
Science,
l
Commercial
and research projects were sponsored by General Motor company, Cabot corp.,
POSCO, Samsung-Corning Precision Glass (
1)
Modeling and Design Experience:
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Developing
a finite element analysis for the press
hardening considering plasticity by the phase transformation of steel (on
going)
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Investigate
constitutive behavior of Transformation
Induced Plasticity (TRIP)
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Developed
a new finite element formulation for the
elasto-plastic strain rate potential, srp2004.
l
Developed
a meso-scale simulation procedure to
study the strengthening mechanism of metallic materials. The new simulation
unit which simulates dislocation density pileup and transmission near the grain
boundaries revealed that the high dislocation densities near the grain
boundaries are responsible for the size dependent strengthening like Hall-Petch
relation.
l
Stress-strain response of
nanocrystalline materials
by Finite Element Method based on rate-dependent crystal plasticity.
Investigate grain size effect and grain spatial distribution effect on the mechanical
response of nanocrystalline material by the binary plastic transformation rule. The method will be applied to
study the phase transformation of shape
memory alloy (cowork with Peter M. Anderson at OSU)
l
Developed
crystal plasticity finite element
program to optimize the deformation texture after upset of Tantalum
material. Various sensitivity tests were carried out to investigate the effect
of process (friction, upset speed) and material (rate sensitivity, hardening
rate etc.) on the final upset texture and stress-strain response.
l Originated a process/material optimization
method to reduce sheet metal springback
after forming. The new constitutive equations were developed and implemented
into commercial FE program ABAQUS
via User Material Subroutine, UMAT/VUMAT.
The new model along with non-linear hardening and non-quadratic yield potential
showed advantages in prediction capability in the automotive industry.
l
Developed
combination type isotropic-kinematic
hardening model to better predict the cyclic behavior of light-weight sheet
materials such as aluminum alloys and high strength dual-phase steel. The
developed constitutive equations were mathematically formulated and implemented
into FE program.
l
Conducted
a series of FEA simulations to improve crashworthiness
of automotive parts. These include numerical sensitivity study on both material
and process parameters.
l
Conducted
thermo-mechanical FE simulations to
reduce the bowing phenomenon in production of thin LCD glass. Visco-elastic
constitutive equations were implemented into static FEM program and sensitivity
tests were performed for the speed of inflow glass melt, upwind speed, speed of
side roller etc.
l
Introduced
anisotropic visco-elasticity to
design high stiffness fiber reinforced composite C-shaped ring. The analytical
and numerical modeling techniques were developed to design the medical device
for the fixation of broken or abnormal bone.
l
Developed
robust contact algorithm to reduce
computational expense in simulation of sheet metal forming. The research
oriented FE code SHEET-3 originally
developed at OSU was modified to include more capabilities such as draw bead,
general tool surfaces etc.
2)
Materials and Metallurgical Experience:
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Room
temperature cyclic tension/compression
tests and drawbend springback tests
for AZ31B magnesium alloy sheets.
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Studied
the microstructural response of BCC
metals after tensile deformation using fine scale Orientation Image Microscopy (OIM) experiments which can capture
the evolution of lattice curvature. Tensile tests, and rolling tests were
conducted for mechanical properties. Co-worked with BYU (research group of
Brent L. Adams)
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Conducted
time independent/dependent springback
tests (the OSU draw-bend tests, in R.H. Wagoner group) to study the
springback phenomenon of several automotive sheets such as aluminum alloy and
high strength steels.
l
Developed
a new tension/compression test device
to prevent buckling during the compressive test of thin sheet metals. Performed
cyclic tests using this device and characterized the unloading and reverse
loading behavior of thin aluminum
alloy, magnesium alloys and DP-Steel sheets.
l
Conducted
bending test of fiber reinforced
composite C-ring. The results showed better prediction capability when the
material is modeled with anisotropic visco-elasticity.
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Fabricated fiber reinforced
composites
including uni-axial laminates and 3-dimensional multi-axial braided structure.
The mechanical properties of highly non-linear polymeric material were measured
and utilized for a novel constitutive equations.
Skills
Language
- Have a good
command of English
Computation
- Finite Element
Program: ABAQUS (UMAT/VUMAT), SHEET-3 (OSU FEM Program), ANSYS, Dyna-3D
- CFD Program: FLUENT
(Certificated user)
- Pre, Post Program:
PATRAN, HYPERMESH, FEMAP, Gambit (Pre for Fluent)
- Programming,
Math Program: FORTRAN (77, 90), C, C++, MATLAB
- Texture
Analysis Software: popLA
Experiments
- Mechanical
testing machine; Instron, MTS, Drawbend Tester (OSU)
- Impact tester
- Fabrication of
composites materials: hot press
- Dilatometer