production of kevlar panels using high pressure resin transfer ... · 2021. 4. 3. · production of...
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Production of Kevlar Panels Using High Pressure
Resin Transfer Molding (HP-RTM) and Liquid
Compression Molding (LCM) Process and Their
Performance
K. Chang, D. Buzzelli, G. Meirson,
O.R Tutunea-Fatan
Fraunhofer Project Centre for
Composites Research
FPC @ Western
A joint venture between:
Western University, London, Ontario, Canada
And
Fraunhofer Gesellschaft, Munich, Germany;
Institute for Chemical Technology (ICT), Pfinztal, Germany
Contact: [email protected]
www.eng.uwo.ca/fraunhofer
Kevlar®
Aramid fibers
Meta-Aramid Para-Aramid
(Kevlar®)
Wet spinning
Semi-crystalline fiber
with molecular chain oriented along the fiber axis
Dry jet wet
spinning
Fully extended liquid
crystal chain along the axis
Can withstand stress
during fire exposure and high temperatures
Incredibly stronghttps://www.dupont.com/fabrics-fibers-and-nonwovens/kevlar-for-aerospace.html
Why Kevlar®?
Extremely strong yet lightweight and
durable, Kevlar® provides the perfect
balance of form and function—allowing you
to redefine performance and explore new
possibilities for a better tomorrow. Whether it’s used for protection, consumer products
or transportation, Kevlar® keeps you at the
forefront of innovation.
Kevlar has a unique combination of high
strength, high modulus, toughness and
thermal stability
https://www.dupont.com/fabrics-fibers-and-nonwovens/kevlar-for-aerospace.html
Kevlar® Fiber properties
Kevlar 49 E-glass Carbon
Modulus [GPa] 112 72 220
Specific tensile strength
[106 cm]
21.25 13.79 17.6
Elongation at break % 1.4 4.8 2.4
Kevlar® fabric:
Woven 175 gsm
HP-RTM LCM
• ~5 minute cycle time
• 3D geometry
• Thick parts
• ~3 minute cycle time
• 2.5D geometry
• Thickness us to ~2.5m
LCM
Research objectives
▪ Explore the process of Kevlar® molding through HP-RTM
▪ Explore the process of Kevlar® molding through LCM
▪ Explore the properties of Kevlar® composites made through HP-RTM and LCM
▪ Explore the properties of hybrid Kevlar®/carbon properties
Composite Manufacturing
RTM Rimstar Thermo 8/4/8 with 2 Mixing Heads
• Self-cleaning mixing head
design
• Separate mixing heads
for epoxy and
polyurethane systems• Internal mold release
system can be used for
third injection component
• Precision dosing between
0.05 - 2.0 g/s• Mixing pressures between
60 and 180 bar
• Resin flow rates: 20 - 120
g/s
• Active pressure/flow monitoring
Composite Manufacturing
• Parallel motion control system
• Maximum closing force of 25,000 kN
(using full parallel motion control force)
• Minimum closing force of 250 kN
• Rapid motion up to 800mm/s ram speed• Precision closing speeds up to 80mm/s
at low force and 20mm/s at high force
Dieffenbacher CompressPlus DCP-U 2500
Manufacturing conditions
• Hexion’s epoxy system Epikote
6150/Epikure 6150
• Mold temperature set to 120◦C
• 5 min curing time
• 1500 kN press force during injection • 4500 kN press force during cure
Kevlar® molding
▪ Kevlar® turned out extremely easy to mold with very wide operational envelop
Kevlar® molding
▪ Since Kevlar is from family on polyamides effect of dehydration was investigated
Water vapors leaving the fabric
Test Dried As is
Compression strength
[MPa]
99.32 97.48
Tension strength [MPa] 440.41 428.75
Flexure strength [MPa] 398.73 391.25
Impact 204.15 201.16
Test Dried As is
Compression modulus
[GPa]
20.05 20.10
Tension modulus [GPa] 26.10 23.86
Flexure modulus [GPa] 21.74 21.43
Sample specification:
2 mm thick panels
50% volume fraction
8 layers of Kevlar®
LCM vs. HP-RTM
Test HP-RTM LCM
Compression
strength
[MPa]
99.01 99.32
Tension
strength
[MPa]
512.50 440.41
Flexure
strength
[MPa]
392.13 398.73
Impact 149.79 204.15
Sample specification:
2 mm thick panels
50% volume fraction
8 layers of Kevlar®
Dried samples
HP-RTM thick vs. thin panels
Test Thick* Thin*
Compression
strength [MPa]
146.86 103.09
Tension strength
[MPa]
514.41 434.21
Flexure strength
[MPa]
407.97 40.32
Impact 141.18 188.46
Test Thick* Thin*
Compression
modulus [GPa]
21.47 22.53
Tension
modulus [GPa]
28.25 28.06
Flexure
modulus [GPa]
25.10 21.53
Sample specification:
Thin*: 2 mm, 50% vol, 8 layers
Thick*: 4 mm, 50% vol, 16 layers
*Fabric was treated with plasma
Kevlar® vs. Carbon composite
Test Kevlar® Carbon
Impact [kJ/m2] 149.79 (188.46 with
plasma)
188.35
Flexure strength
[MPa]
392.13 939.88
Flexure [GPa] 21.21 49.00
Sample specification:
Kevlar®:
50% volume, 8 layers
2 mm thickness
Carbon:
50% volume, 6 layers
2 mm thickness
Hybrid composite
Test Kevlar® (8K) Carbon
(6C)
2C/3K/2C K/6C 3C/K/3C
Impact [kJ/m2] 149.79(188.46P) 188.35 201 228.40 221.11
Flexure strength
[MPa]
392.13 939.88 1059.19 886.34(KT)
1052.21 (KT)
1104.42
Flexure [GPa] 21.21 49.00 59.39 52.00 61.41
52.2% vol 56% vol 56% vol
Summary
▪ Kevlar® was extremely easy to mold
▪ Kevlar has good compatibility with epoxy resin
▪ Adding Kevlar® to carbon in small amounts provides a lot of added value in
terms of properties
▪ In some cases Plasma has provided significant increase in properties
Acknowledgments
▪ We would like to thank DuPont for funding the project
▪ We would like to thank NSERC for funding the project
▪ We would like to thank Hexion for donating the epoxy resin for the project
▪ We would like to thank Plasmatreat for proving the plasma equipment for the
project