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ESTIMATION OF THE REMAINING LIFETIME ON COMPOSITE MATERIALS BY MODELING THE ACOUSTIC EMISSION APPEARANCE RATE
M. Darwiche (LAUM - ESEO),
G. Bousaleh (Libanese University),
D. Schang (ESEO),
R. El Guerjouma (LAUM)
Overview
• Motivations
• Test
• Method
• Results
• Conclusion and Perspectives
2M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Motivations
3M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Motivations
4
Type of material
Lifetime prediction
Type of damage
“The use of composite materials is becoming of greater interest in different industrial fields, especially aircraft, aerospace, naval industry, etc… ”.
Some studies are needed to guaranty the proper functioning of the materials:
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Motivations
5
“The use of composite materials is becoming of greater interest in different industrial fields, especially aircraft, aerospace, naval industry, etc… ”.
Some studies are needed to guaranty the proper functioning of the materials:
Lifetime prediction
Type of damage
Type of material
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Motivations
Lifetime prediction : creep test
Seven tensile specimens have been tested (8 plies unidirectional fiberglass reinforced with resin) with the same stress level
Seven different rupture time : (539s, 159s, 3362s, 1831s, 992s, 145s and 845s).
200
mm
20 mm
6M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Test
7M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
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Creep test monitored using acoustic emission
Creep test : a constant stress is applied
Acoustic emission device
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
time
Am
plit
ude
(•) signals N°
> 70 > 35> 20> 9 > 4 < 4
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Creep test monitored using acoustic emission
Acoustic Emission distribution versus time
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Phase 1: Dramatic increase of acoustic emission due to the macromolecular connections.
Phase 2: The acoustic activity is low, the deformation varies linearly with time. It’s the most dominant phase throughout the creep test.
Phase 3: is characterized by a sudden acceleration of the AE rate causing the rupture of the material.
Test
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1
2
3
Cum
ulat
ive
num
ber
of s
igna
ls
time
Acoustic Emission distribution versus time
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Test
11
1
2
3
Cum
ulat
ive
num
ber
of s
igna
ls
time
Challenge : predict the rupture time of a tensile specimen from the reference time tref
tref
tr
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Method
12M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Method
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Normalization technique
AEreconstruction
Reference time detection
1
2
3
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Method
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CS’ = CS / NT Є [0, 1] ; CS: cumulative number of AE, NT: total number of AEt’ = t / tr Є [0, 1]; t: time, tr: rupture time
1. Normalization technique
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Method
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All samples normalized
1. Normalization technique
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Method
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2. Polynomial reconstruction
Best fitting=
Minimal error
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Method
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3. Reference time detection
derivation
derivation
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Method
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3. Reference time detection
Reference time localization after 50% decrease the AE rate
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
tre : reference time localized after 50% decrease the AE rate
error :
Specimen 1
Specimen 7
Method
Model creation
test
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6 tensile specimen
Specimen 1
• To guarantee the performance :- K-fold cross validation (K=7)- one cross validation :
Specimen 7
Specimen 2
Specimen 3
Specimen 4
Specimen 5
Specimen 6
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Results
20M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Results
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Looking for other reference times
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Reference time localization after the decrease of the AE rate by : 10%, 20%, 30%, 40%, 50%, 60%, 70% and 80%
Results
22M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
mref : mean value of tref tre : estimated rupture time er : error
Rupture time estimation from tref10%, tref 20%,tref 30%, tref 40%, tref 50%, tref 60%, tref 70% and tref 80%
mref : mean value of tref tre : estimated rupture time er : error
Results
23M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Rupture time estimation from tref10%, tref 20%,tref 30%, tref 40%, tref 50%, tref 60%, tref 70% and tref 80%
Results
24M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Comparing resultsBest results
Conclusion
25M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
Conclusion
An interesting step for lifetime prediction…
if we have a specimen on use, ones we can localize tref and then estimate the remaining lifetime.
26
Perspective: looking for relation into the second phase to estimate the remaining lifetime
M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
with tref10%, we can estimate the rupture time from 0.4% of the integral lifetime with an error about 6.36%
Questions
Thank you…
Any questions ?
Any suggestions ?
27M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "
