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)

mohamad.darwiche@hotmail.com

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 "

8

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

9

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

10

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

13

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

15

All samples normalized

1. Normalization technique

M. Darwiche " estimation of the remaining lifetime on composite materials by modeling the acoustic emission appearance rate "

Method

16

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

17

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

19

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

21

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.

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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 "