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Materials Processing and Manufacturing: Novel Processes and ModelingContact: Prof. Donggang Yao; email: [email protected]
School of Materials Science & Engineering
Georgia Institute of Technology
School of Materials Science and Engineering
Research Interest: 1. Development of new methods for precision polymer fabrication,
blends processing, composites processing, gel spinning of ultrastrong fibers, and processing of bulk metallic glasses.
2. Constitutive modeling: rheology of immiscible polymer blends, nonlinear viscoelasticity, and deformation at micro/nano scales.
3. Dynamics of materials processing: modeling of non-Newtonian flow, finite-strain deformation, and blend dynamics.
4. Computational materials science: molecular dynamics, finite element analysis, and multiscale simulation.
Selected Processes:• Two-station embossing
• Rubber-assisted micro forming
• Rapid-thermal-response micro injection molding
Rapid heating Embossing Holding/cooling Demolding
Rapidly heated
Forming & cooling Opening Part ejection
Master moldMicro formed film
Rubber
Preheating
Selected Parts/Structures:
100
100μ 50μ
• Micropatterning of porous structuresHot embossing
Sacrificial extraction& formation of porous
patterns
Co-continuous blending
A
B
• Extrusion roll-to-roll micro/nano imprinting
p
T1
T2
T3
Imprinting zoneR2
R1
R3
Film Direction
Induction Heating
Pressure Rollers
Belt Mold
60
80
100
120
140
160
180
200
0 5 10Time, seconds
Tem
pera
ture
, °C
H.F. in H.F. out
B
Stationary half
Moving half
CDE
FGH
IA
• Gel spinning of ultra-strong fibers
Constitutive Modeling:
Deform
Deform
Oriented phase structure Non-orientedNon-oriented
• Nonlinear viscoelasticity with a microstructure tensor
daVV
a nnIIT33
2
')''(:)(0
1
0
daVJU
nnCF
BB
IT AA 2
Dynamics of Polymer Processing:
200µm 50µm 25µm 5µm
25µm50µm100µm200µm
Depth:
We acknowledge the financial support from NSF under Awards 0238033, 0503138, 0620668, 0637784, 0712305, 0800016, 0826259, 0848524, 0927697, 1462101, 1927651, and 2027871, as well as support and partnership from industrial partners and sponsors.
Acknowledgements
R2
R1
R3
R4Cold
WarmHot
Coagulation bath
Wind up Roll
Rollers
Spinhead
Polymer solution
Gellation
Precursor Drawing & heat treatment
Heated rolls
High-performance fiber with E > 150 GPa and > 4.5 GPa
←
T
Gradient structures
0.1
1
10
100
1000
10000
1 10 100 1000
Rhe
olog
ical
Pro
perti
es
N1, predicted in Pa(-N2), predicted in Pa, predicted in Pas
BIT
BBB
)/1(
ln)/1(
1
00
00
SSGp
SS
• Plastic processing of metallic alloysBulk metallic glasses
Nonisothermal embossing
Noncircular fiber spinning Injection molding
Extrusion
Micro-thermoforming
Blends processing
• Novel extrusion and fiber spinning processes
