comparison of the tensile properties of 3d woven …...comparison of the tensile properties of 3d...
TRANSCRIPT
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 1
Comparison of the tensile properties of 3D woven and plain woven composites
Alexander Bogdanovich, Dmitry Mungalov, 3Tex, USA
Dmitry S. Ivanov, Stepan V. Lomov, Ignaas VerpoestDepartment MTM, K.U. Leuven
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 2
Contents
• 3D glass fabric and plain woven laminate• Test methodology and equipment• Results
– Elastic constants and tensile diagrams– Damage initiation and AE diagrams
• Conclusions
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 3
• 3D glass fabric and plain woven laminate• Test methodology and equipment• Results
– Elastic constants and tensile diagrams– Damage initiation and AE diagrams
• Conclusions
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 4
Problem statement
Composites fabricated by VARTM technology with the use of relatively thick, single layer 3D woven preforms are gaining fast growing interest. It is now well understood and appreciated that this class of advanced composites provides efficient delamination suppression, damage tolerance, and is superior over 2-D fabric laminates in impact, ballistic and blast performance. However, one primarily important question has not been convincingly answered yet: how do the in-plane elastic and strength characteristics compare for 3-D woven composites and their laminated 2D fabric counterparts.
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 5
Aim
Compare 3D woven composite and plain weave laminate basic in-plane elastic and strength properties:
a single layer (unitary) 3D woven composite vsrespective properties of 2D fabric laminate
• same glass rovings inside
• equivalent areal density;
• equivalent thickness and fibre volume fraction,
• fabricated by identical methods
• in the same laboratory conditions
+ provide validation data for WiseTex/TexComp, MOSAIC, FE modelling
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 6
Internal structure of 3D and plain weave composites
Plain weave laminate
Note: 1. Slight crimp of the fill caused by compaction in VARTM
2. Almost rectangular shape of the cross-sections
Crimped warp/weft, nested plies
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 7
Parameters of 3D and plain woven fabric
2.76Z-yarns per cm
2.64Picks per cm
1470layer 2,3
1470layer 1,4
Fill (double yarns)
276Z-yarns
1100layer 2
2275layer 1,3
Warp
texYarns
48.9VF, %
2.76Ends (straight) per cm per layer
2.6Thickness, mm
3255Areal density, g/m2
1 plyFabric and composite plate
3D – GE044 Plain weave
6.19Picks per cm
2275Warp and weft
texYarns
52.4VF, %
5.08Ends per cm
2.45Thickness, mm
3260Areal density, g/m2
4 plyFabric and composite plate
4 plies: 0°/90°/90°/0°
Warp : Fill : Z = 49% : 48% : 2%
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 8
• 3D glass fabric and plain woven laminate• Test methodology and equipment• Results
– Elastic constants and tensile diagrams– Damage initiation and AE diagrams
• Conclusions
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 9
Tensile test with acoustic emission
ASTM D3039M – 00 INSTRON 4505Sample 250x25 mm (gauge 180 mm)Load cell 100 kNSpeed 1 mm/min
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 10
Acoustic emission: Events and cumulative energy diagram
1.00E+00
1.00E+01
1.00E+02
1.00E+03
1.00E+04
1.00E+05
1.00E+06
1.00E+07
1.00E+08
1.00E+09
0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00
sig, MPa
ener
gy
H1 H2
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 11
Optical extensometer: LIMESS –Vic2D
� �,avex x x yH H
� �,avey y
avexavey
x yH H
HQ
H
�
Apart from the averaging, surface strain fields are available
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 12
Optical damage observation
The samples were placed in between the lamp and the camera. The lamp was directed at a frame with Teflon sheet (to get homogeneous illumination), where the samples were fixed. Several images over the length of the samples were made.
No cracks are found on the initial undeformed samples.Cracks could be seen on all the samples at H1 and H2
3D sample loaded to H2
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 13
Plan of the tests
6-++H29+++H13--+Ultimate
9+++Poisson
9+++Young
18
9533BD
9333MDPlain weave
27
9333BD
9333CD
9333MDGE044
TotalTill eps1Till eps2Till failureDirectionFabric
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 14
• 3D glass fabric and plain woven laminate• Test methodology and equipment• Results
– Elastic constants and tensile diagrams– Damage initiation and AE diagrams
• Conclusions
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 15
Elastic constants
Moduli, normalised @50%
0
5000
10000
15000
20000
25000
30000
Warp Fill 45
E, M
pa GE044PW
Poisson coefficients
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Warp Fill 45
Poi
sson GE044
PW
- No difference in Young moduli
- Decreased Poisson for the 3D fabric (inside the scatter?)
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 16
Tension diagrams
Tension in warp/fill direction, normalised @VF=50%
0
100
200
300
400
500
600
0 1 2 3 4
strain, %
stre
ss, M
Pa
GEO44, warpGEO44, fillPW
Tension in 45° direction(up to failure)
-20
0
20
40
60
80
100
120
140
0 5 10 15
strain, %
stre
ss, M
Pa
GEO44PW
- No difference in diagrams
- Nonlinearity in fibre direction from eps1
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 17
Strength
Strength @50%
0
100
200
300
400
500
600
Warp Fill 45
Stre
ngth
, MP
a
GE044PW
Ultimate elongation
0
2
4
6
8
10
12
14
16
Warp Fill 45
Stre
ngth
, MP
a
GE044PW
3D composite: higher strength (+10%), higher elongation
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 18
Damage thresholds
Damage strain thresholds
0
0.2
0.4
0.6
Warp Fill
Stra
in, %
GE044, eps1GE044, eps2PW, eps1PW, eps2
3D composite:
- increase of damage initiation thresholds by 0.2% strain for loading in fibredirection
- advantage in fatigue life stress limit can be expected
- lower damage thresholds for loading in bias direction
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 19
AE diagramsTypical AE registration, warp/fill test direction
1.00E+03
1.00E+04
1.00E+05
1.00E+06
1.00E+07
1.00E+08
1.00E+09
0 0.5 1 1.5 2
strain, %
AE
ene
rgy
3D_W_p1_1events3D_F_p1_4eventsPW_W_p1_1events
Typical AE registration, 45° test direction
1.00E+03
1.00E+04
1.00E+05
1.00E+06
1.00E+07
1.00E+08
1.00E+09
0 5 10
strain, %
AE
ene
rgy 3D_45_p2_3
eventsPW_45_p2_2events
- shift of the threshold strains
- higher energy of the events for 3D composites
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 20
Damage development (loading in fibredirection)
3D warp
3D fill
plain weave
eps_1 eps_2 eps_ULT
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 21
Damage development (loading in bias direction)
3D 45°
plain weave 45°
eps_1 eps_2 eps_ULT
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 22
LIMESS strain field registration (to be further processed)
The red spots indicate the crack positions
3D plain weave
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 23
• 3D glass fabric and plain woven laminate• Test methodology and equipment• Results
– Elastic constants and tensile diagrams– Damage initiation and AE diagrams
• Conclusions
downloaded from: http://www.mtm.kuleuven.ac.be/Research/C2/poly/index.htm 24
Conclusions
1. 3D and 2D woven glass/epoxy composite mechanical properties and damage behaviour in tensile test have been compared in the equivalent composite parameters, production and testing conditions
2. Elastic constants of 3D and 2D woven composites are very close
3. 3D woven composites show increased strength and damage initiation thresholds then their 2D woven analogs
4. Damage development in glass/epoxy 3D woven composites conforms to the scheme established earlier for 2D woven, braided, non-crimp carbon/epoxy composites