Transcript of 5th International Conference on Composites Testing and Model Simulation Samuel Stutz Joël Cugnoni...
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- 5th International Conference on Composites Testing and Model
Simulation Samuel Stutz Jol Cugnoni John Botsis 1 LMAF-STI, Ecole
Polytechnique Fdrale de Lausanne (EPFL), CH-1015 Lausanne
Switzerland E-mail: samuel.stutz@a3.epfl.ch
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- 5th International Conference on Composites Testing and Model
Simulation Increasing use of composites Layered structure
Delamination Characterization of propagation Introduction Method
Results & Discussion Conclusion 2
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- 5th International Conference on Composites Testing and Model
Simulation Approach: Measuring strain with optical fibre sensors
during crack propagation Identify relevant properties with a
parametric FE-model Comparing the numerical and experimental load-
displacement curve 3 Introduction Method Results & Discussion
Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation Method Manufacturing Multiplexed Fiber Bragg grating
(FBG) sensors Distributed strain measurements Results &
Discussion Mode I (DCB) tests Mode II (4ENF) tests Conclusion
Introduction Method Results & Discussion Conclusion 4
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- 5th International Conference on Composites Testing and Model
Simulation Prepregs from Gurit SP TM (SE 70) [0 20 ] Introduction
Method Results & Discussion Conclusion 5 Sensor fibre Crack
Crack initiator
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- 5th International Conference on Composites Testing and Model
Simulation Introduction Method Results & Discussion Conclusion
6 =2n
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- 5th International Conference on Composites Testing and Model
Simulation Introduction Method Results & Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation Introduction Method Results & Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation Introduction Method Results & Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation Introduction Method Results & Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation No strain at the FBG positions Strain ahead of the crack
tip reaches the FBGs All FBGs are in the bridging zone 11
Introduction Method Results & Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation No strain at the FBG positions Strain ahead of the crack
tip reaches the FBGs All FBGs are in the bridging zone 12
Introduction Method Results & Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation No strain at the FBG positions Strain ahead of the crack
tip reaches the FBGs All FBGs are in the bridging zone 13
Introduction Method Results & Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation Wavelength shift versus time 14 Introduction Method
Results & Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation Wavelength shift versus time 15 Introduction Method
Results & Discussion Conclusion Strain versus crack length
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- 5th International Conference on Composites Testing and Model
Simulation Wavelength shift versus time 16 Introduction Method
Results & Discussion Conclusion Strain versus crack length
Using crack length versus time measurements to eliminate time
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- 5th International Conference on Composites Testing and Model
Simulation 17 Introduction Method Results & Discussion
Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation 18 Introduction Method Results & Discussion
Conclusion Algorithms: Trust-region-reflective
Levenberg-Marquardt
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- 5th International Conference on Composites Testing and Model
Simulation 19 Introduction Method Results & Discussion
Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation 20 Introduction Method Results & Discussion
Conclusion Crack opening as a function of the distance from the
crack tip (from simulation) (z*) and the identified bridging
traction distribution (z*) were combined to obtain the bridging law
( )
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- 5th International Conference on Composites Testing and Model
Simulation 21 Introduction Method Results & Discussion
Conclusion Cohesive element properties: Thickness : 20 m Damage
initiation : 20 MPa Cohesive stiffness : 9000GPa/mm G(a) = G i + G
b (a)
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- 5th International Conference on Composites Testing and Model
Simulation Experimental load- displacement curve Two initial crack
lengths, 30 and 60 mm 22 Introduction Method Results &
Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation Simulated load - displacement curve No bridging in the
cohesive law 23 Introduction Method Results & Discussion
Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation Simulated load - displacement curve With bridging in the
cohesive law Energy release rate of the bridging fibres: 350 J/m 2
24 Introduction Method Results & Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation 25 Introduction Method Results & Discussion
Conclusion Fibre end
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- 5th International Conference on Composites Testing and Model
Simulation 26 Introduction Method Results & Discussion
Conclusion Using crack length versus time measurements to eliminate
time
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- 5th International Conference on Composites Testing and Model
Simulation 27 Introduction Method Results & Discussion
Conclusion Identified energy release rate (cohesive elements) G II
=1070 J/m 2 Identified crack initiation: max = 38.7 MPa Identified
friction between the loading pins and the sample: =0.35 There was
no sensitivity to friction between the fracture surfaces ( =0.1
0.4)
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- 5th International Conference on Composites Testing and Model
Simulation Experimental load-displacement curves The different
slopes are due to different initial crack lengths Some unstable
crack propagation 28 Introduction Method Results & Discussion
Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation Results from the numerical simulation Cohesive elements
with the identified properties 29 Introduction Method Results &
Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation The multiplexed FBG sensor array proved to be an
excellent embedded sensor to measure non-homogeneous strain in mode
I and mode II delamination The measured strain distribution was
successfully used for identification of material parameters o
Bridging tractions in mode I o The energy release rate in mode II
The experimental load displacement curves were entirely reproduced
30 Introduction Method Results & Discussion Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation The authors acknowledge the financial support from the
Swiss National Science Foundation (SNF) under Grant 200020_124397.
31 Introduction Method Results & Discussion Conclusion
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Simulation 32 Introduction Method Results & Discussion
Conclusion
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- 5th International Conference on Composites Testing and Model
Simulation 33 Introduction Method Results & Discussion
Conclusion