Understanding the High Temperature &
Fire Performance of Composites
AP Mouritz
Royal Melbourne Institute of Technology (RMIT University)
e-mail: [email protected]
Research overview
•
Understand high temperature & fire response of
composites for diverse structural applications
•
Understand following about composites in fire:
•
•
•
•
thermal response
damage & decomposition
softening & failure
residual mechanical properties
•
Fire modelling & testing:
• Material level (fibre/ply/laminate)
• Structural level (component)
•
Material systems:
• fibre-polymer laminates
• sandwich composites
• fibre metal laminates
2
Research vision
Towards a user-friendly generic modelling “toolbox” to predict
thermal response, damage, burn-through & structural
integrity of composites during & following fire exposure.
Research progress
• Models to predict temperature rise in laminates &
sandwich composites exposed to fire.
• Models to predict decomposition & burn-through in
laminates & sandwich composites exposed to fire.
• Models to predict softening & failure of laminates &
sandwich composites exposed to fire.
• Models to predict post-fire mechanical properties of
laminates & sandwich composites exposed to fire.
• Models to predict fire protection provided by
passive and reaction coatings on laminates &
sandwich composites exposed to fire.
4
Experimental validation
Experimental validation at different length scales
has been central to our models
increasing experimental scale
Fibre damage (<10 microns)
Microstructural damage (<1 mm)
Coupon testing (<0.5 mm)
Intermediate-scale testing (1 m)
Large-scale testing (3 m)
Thermal Analysis of
Hot, Decomposing Composites
6
Thermal model
Heat Flux
Fire reaction of polymer laminates & sandwich composites is
a complex interactive problem
Fire-damaged
carbon/epoxy laminate
Thermal model
• Model developed to calculate temperature for any thermal flux condition
of the fire.
• Model validated for composites tested at heat flux conditions from 10
kW/m2 (~250oC) to 100 kW/m2 (~800oC).
Heat Flux
solid lines represent predictions
Decomposition Analysis of Composites
9
Decomposition model
Decomposition of laminates & sandwich composites to char is
calculated using Arrhenius rate model.
Measured Char Thickness = 5.78 ± 1.23 mm
Heat Flux
Remaining Resin Content (%)
100
solid line represents predictions
80
60
Glass/polyester fabric
40
20
0
0
charmodel25.opj
char
virgin
laminate
2
4
6
8
Depth Beneath Hot Face (mm)
10
12
Decomposition model
Accurate prediction of decomposition (char) for many
composites under range of heat flux conditions.
2
12
carbon/epoxy tape (50 kW/m )
2
Measured Char Thickness (mm)
carbon/epoxy tape (75 kW/m )
2
carbon/epoxy tape (100 kW/m )
10
2
carbon/epoxy fabric (50 kW/m )
2
glass/polyester fabric (25 kW/m )
2
glass/polyester fabric (50 kW/m )
8
2
glass/polyester fabric (75 kW/m )
2
glass/polyester fabric (100 kW/m )
6
2
glass/epoxy fabric (50 kW/m )
2
glass/vinyl ester fabric (25 kW/m )
2
glass/vinyl ester fabric (50 kW/m )
4
2
glass/vinyl ester fabric (75 kW/m )
2
glass/vinyl ester fabric (100 kW/m )
2
2
glass/phenolic fabric (25 kW/m )
2
glass/phenolic fabric (50 kW/m )
2
glass/phenolic fabric (75 kW/m )
0
2
0
2
4
6
8
10
Theoretical Char Thickness (mm)
charmo del 27.op j
12
glass/polyester mat (50 kW/m )
2
glass/epoxy mat (50 kW/m )
Softening & Failure of Composites
12
Compression model
Compression properties of polymer laminates &
sandwich composites exposed to fire
Compressive
Load
1. Calculation of through-thickness temperature
profile in composite
2. Calculation of temperature-dependent
compression strength (matrix softening) at
many points through the composite
3. Calculation of bulk strength of the composite
4. Prediction of compression failure.
Heat Flux
Modelling based on the four step analysis:
Compressive
Load
Compression model
Experimental validation of compression model using laminates
& sandwich composites.
Compression model
Model validation for polymer laminates & sandwich composites
failure time decreases with
increasing applied stress & heat flux
Normalised Compressive Stress
1.0
glass/vinyl ester laminate
0.8
0.6
2
o
25 kW/m (440 C)
0.4
2
o
50 kW/m (600 C)
0.2
2
0.0
plastic kinking failure
o
75 kW/m (800 C)
0
300
600
900
Time-to-failure (s)
1200
1500
Tension model
Tension properties of polymer laminates & sandwich
composites exposed to fire
Tension
Load
Modelling based on the five step analysis:
1. Calculation of through-thickness temperature
profile in composite
2. Calculation of temperature-dependent
tension strength of polymer matrix at many
points through the composite
3. Calculation of temperature-time dependent
strength of fibres at many points through the
composite
4. Calculation of bulk tensile strength of the
composite
5. Prediction of tensile failure.
Tension
Load
Tension model
Experimental validation of tension model using laminates &
sandwich composites
Tension model
Experimental validation of tension model.
Failure can occur after complete matrix decomposition.
Applied tensile stress (MPa)
250
solid lines represent predictions
Tension
Load
200
150
100
50
0
1
10
100
Time (s)
1000
Tension
Load
Outstanding research problems
• Past ten years characterised by major progress in
fire modelling of composites.
• However, challenges remain.
– Mechanistic-based models for softening & oxidation of
fibres at high temperatures.
– Model for predicting delamination cracking in hot,
decomposing composites
– Model for various damage & failure modes of sandwich
composites in fire
– Scaling laws
– Comparative studies with structural metals
– User-friendly modelling toolbox for composites in fire.
• A.P. Mouritz, S. Feih, A. Afaghi Khatibi, B.Y. Lattimer and S.W. Case, United States Office of Naval Research Grant, ‘Fire
Modeling and Testing of Aluminum Alloys and Structures’, 2013-2016, N000141310590.
• A.P.Mouritz United States Office of Naval Research, International Workshop on Naval Structural Life Assessment Methodologies,
2011, N62909-11-1-7031.
• S. Feih, A.P. Mouritz, S.W. Case and A.P. Mouritz, United States Office of Naval Research, ‘Deformation modelling of naval
composite structures in Fire: Sensitivity Analysis and Optimization’, 2010, N00014-11-1-0223.
• S. Feih, A.P. Mouritz, S.W. Case and A.P. Mouritz, United States Office of Naval Research, ‘Fire Structural Properties of
Sandwich Composites’, 2010, N00014-12-1-0248.
• A.P. Mouritz, S. Feih, B.Y. Lattimer and S.W. Case, United States Office of Naval Research Grant, ‘Modeling of Aluminum Naval
Structures During and Following Fire’, 2010-2012, N00014-10-1-0690.
• A.P. Mouritz, United States Office of Naval Research Grant, ‘Development and Application of Fire Resistive Models for Naval
Composite Structures’, 2007-2009, N00014-07-0514.
• B. Lattimer and A.P. Mouritz, United States Office of Naval Research Grant, ‘Structural Integrity of Aluminum during Fires’, 20072009, N00014-08-1-0300.
• A.P. Mouritz, United States Office of Naval Research Grant, ‘Structural properties of composites in fire’, 2003-2006.
• A.P. Mouritz, United States Office of Naval Research Grant, ‘Fire book’, 2002
20
• Dr Stefanie Feih
(RMIT)
• Dr Everson Kandare
(RMIT)
• Ms Katherine Grigoriou (RMIT)
• Ms Zenka Mathys
(DSTO)
• Prof Geoff Gibson
(Uni. Newcastle)
• Prof Scott Case
(Virginia Tech)
• Prof Brian Lattimer
(Virginia Tech)
21