Index – Failure Mechanisms in Polymer Matrix Composites

Index

A

acid digestion, 357–8
acoustic emission, 421
Advanced Subsonic Technology Composite Wing Program (NAS1-20546), 252
aerodynamic lift loads, 230
aerospace structures
alternate joint concepts, 259–66
advanced preforms, 263–4
categories of damage and defect considerations, 266
damage tolerance analysis considerations, 265
load vs displacement data, 262
lower cover panel for stitched/RFI composites technology, 260
scaling and hybrids, 264–6
schematic of PRSEUS, 263
stitched joints, 259–60
X-48B Blended Wing Body flight research vehicle, 264
Z-pinned joints, 260–2
design considerations, 229
designing for damage in composites, 248
environmental considerations, 232–41
Astrostrike and Dexmet, 235
bird strike, 233–4
effects of lightning strike protection, 237
impact damage due to hail, 240
lightning strike, 234–7
lightning strike zones as defined in SAE ARP5414, 236
microcracking due to combined thermal-moisture cycling, 238
moisture: rain and ice, 237–41
near-surface damage in honeycomb-sandwich structures, 240
failure mechanisms considerations in polymer matrix composites, 227–71
automated tape-laying machine, 268
comparison of residual strength vs damage, 271
direct braiding of I-beam cross-section and Robotic single-sided stitching, 269
forward section of Boeing 787 Dreamliner fuselage, 269
percentage growth in both commercial and military aircraft structure, 267
materials-based approaches, 248–55
impact damage in a composite laminate, 251
liquid-moulding and prepreg-based toughening, 251–2
low velocity impact damage, 250
toughening in prepregs, 249–51
non-environmental considerations, 241–8
aftermath of crash and fire of composite-based Air Force B-2 bomber, 245
collapsed MD-80 landing gear, 247
fire safety, 244–6
flame impingement from a simulated engine fire, 245
fluids, 241–2
glass transition temperature schematic, 242
ground-based damage due to human error, 246–8
high-speed airflow, 243–4
oil-burner test, 246
temperature, 242–3
preform-based toughening, 252–5
interlayers, 253–5
stitching, 252–3
tackifiers, 253
VARTM-processed multiaxial preforms, 254
structural considerations, 229–48
BVID schematic where the dent depth must be above predetermined critical size, 233
determination and design considerations for in-flight loads, 229–31
impact damage and delamination, 231–2
impacted untoughened carbon/epoxy composite, 232
ultimate-load wing up-bending test on 787 Dreamliner static test unit, 231
structures-based approaches, 255–66
alternate lay-up considerations, 256–9
boiled structures, 255–6
variables influencing fuselage design, 257
Airbus A350XWB, 237
Airy stress function, 94
American Cyanamid, 250
American Society for Testing and Materials, 395
analytical modelling, 425–30
tensile strength half-life vs temperature for E-glass/polyester, 426
traverse flexure properties of E-glass/epoxy laminate, 427
ARALL (aramid-aluminium laminate), 266
Arcan jig, 172, 173
Argon’s approach, 198
Arrhenius equation, 82
Arrhenius law, 415
Arrhenius model, 425, 429
artificial weathering, 423–5
ASTM C273, 306
ASTM C365, 306
ASTM C581, 418
ASTM D695, 141, 170
ASTM D1879, 413
ASTM D3171, 132
ASTM D3681, 420
ASTM D4102, 416
ASTM D5229, 132
ASTM D5528, 112
ASTM D3846-94, 170
ASTM D790M, 164
ASTM D2344M, 169
ASTM D3039M, 135, 137, 139
ASTM D3410M, 140
ASTM D3518M, 152
ASTM D4255M, 158, 160
ASTM D5379M, 155, 160, 169
ASTM D5448M, 151–2, 172
ASTM D6272M, 164
ASTM D6415M, 167
ASTM D7078M, 160
ASTM D7264M, 164
ASTM E1922, 117, 119, 122
automated tape-laying (ATL) machine, 267
automated tow placement (ATP), 268

B

balsa wood, 303
barely visible damage, 67, 73
barely visible impact damage, 231–2, 279
beam theory, 112
Bernoulli–Euler assumption, 90
Berry’s method See compliance calibration method
biaxial in-plane testing, 172–5
biaxial in-plane Arcan test, 175
Arcan jig and specimen set-up, 175
cruciform specimens, 174
cruciform specimen with thickness reduction of the gauge section, 174
off-axis specimens, 174–5
tubular specimens, 172–4
biological degradation, 413–14
bird strike, 233–4
‘black aluminium’, 256
Boeing 787 Dreamliner, 237
British Standards Institute, 395
brittle fracture mode, 383
BS 4994, 420
BS 5480-2, 420
BS EN 13121, 418
BS EN ISO 527, 135
Budiansky–Fleck kink band solution, 102

C

calcium carbonate, 353
carbon black, 413
carbon fibre reinforced plastic (CFRP), 56
Celanese fixture, 140
char formation, 355
chemical degradation, 401–6
chemical resistance of various glass fibres, 404
chemical resistance of various thermosetting resins, 407
chlorine degradation and HCl induced blistering of GRP, 405
failure of a GRP structure due to alkaline aqueous solution, 403
helical cracks in e-glass fibres exposed to H2SO4, 402
chemical recycling, 353–6
cracking technologies, 354–6
fluidised bed, 355–6
pyrolysis, 354–5
gasification, 353–4
two-stage process, 354
chemical resistance testing, 418–23
criteria for chemical resistance, 420
partial design factor A2, 421
screw-jack test machines with samples, 423
strain corrosion test apparatus for cylindrical section, 421
closed mould forming methods, 333
CODAM model, 387–8
coefficient of thermal expansion (CTE), 30
combustion, 352–3
Comité Européen de Normalisation, 395
Commission Directive 200/53/EC, 339
Commission Directive 2002/96/EC, 339
compliance calibration method, 113
compression after impact (CAI), 231, 248, 258
conservation of mass, 82
contact stress, 72
correlation factors, 430
crashworthiness
polymer matrix composites, 382–8
axial crushing of composite tubes, 385
energy absorptions in quasi-static and dynamic tests, 387
energy dissipation mechanisms, 385–7
experimental and predicted load-displacement diagrams, 386
failure modes, 383–5
modeling of progressive crushing, 387–8
parameters in crashworthiness studies of composite tubes, 384
critical strain energy release rate, 113
critical stress intensity factor, 118
crush pressure, 330–1
crystal plasticity theory, 98
Curv, 361

D

defect, 26
defence applications See military applications
delaminations, 32, 227
depolymerisation technologies, 356–8
acid digestion, 357–8
gycolysis, 357
hydrolysis, 356–7
solvolysis, 356
design safety factor, 105
diethylene glycol monoethyl ether (DGME), 404
digital image correlation (DIC) techniques, 133
discontinuous recycled composites, 218
dissolved/distributed thermoplastic approach, 249–50
domain integral, 105
double cantilever beam (DCB), 112–14
double notch compression (DNC) test, 170–1
dough moulding compounds, 342
drape, 37
drop weight testing, 314
Drucker–Prager model, 210
dynamic loads, 230
Dyneema, 241

E

E-glass fibres, 303
eco-composites, 360
ECR-glass, 402–3
effective average plate stiffness, 61
end-loaded split (ElS), 114–15
energy absorption, 387
environmental induced failure
chemical agents and degradation mechanisms, 395–414
biological degradation, 413–14
chemical degradation, 401–6
elevated temperature and thermo-oxidation, 410–11
environmental stress corrosion cracking, 406–10
high-energy radiation, 413
moisture degradation, 395–401
watering and photo-oxidation, 411–13
environmental stress corrosion cracking, 406–10
flexure fatigue curves for GRP rods in porewater solution, 409
HCl induced SCC and discolouration, 408
optical micrograph of failed GRP pipe, 408
self-stressing four-point bending fixture with GRP pultruded rod specimens, 409
environmental testing, 414–30
artificial weathering, 423–5
chemical resistance testing, 418–23
moisture conditioning and testing, 416–18
thermal ageing, 415–16
equilibrium conditioning, 416
extensibility, 50
extensometers, 133
extrapolation, 430

F

FAA Flame Propagation test, 245
failure criteria
progress for polymer matrix composites, 3–22
aims of the first World-Wide Failure Exercise, 5–7
current activities, 17–22
description of available models, 9
design problems solved, 9–17
gaps identified, 17
setting up test problems, 7–9
failure envelopes, 191
Faraday cage, 237
fatigue, 377–80
fatigue strength of SMC-R composites, 378
modulus degradation during fatigue cycling, 379
S-N diagrams of SMC-R25 and SMC-R65, 378
fatigue failure, 370
Federal Aviation Administration (FAA), 229
Federal Aviation Regulations (FAR), 229
feedstock recycling See chemical recycling
fibre-dominated compressive failure
physics of fibre kinking in unidirectional plies, 184–203
analytical modelling, 196–201
experimental observations, 184–90
failure modes in unidirectional composites in longitudinal compression, 184
numerical modelling, 191–5
polymer matrix composites, 183–219
recycled composites, 213–18
short-fibre recycled composites, 213–16
woven recycled composites, 216–18
two-dimensional woven composites, 203–12
analytical modelling, 208
experimental observations, 203–7
numerical modelling, 209–12
fibre kinking, 214
analytical modelling, 196–201
failure envelopes predicted by a finite fracture mechanics based criterion, 202
model development under pure longitudinal compression, 199
results for kink-band formation under pure longitudinal compression, 200
experimental observations, 184–90
combined in-plane shear and longitudinal compression failure envelopes, 188–9
fibre fracture during kink-band formation, 186
kink-band formation in notched unidirectional composites, 185
shear-driven fibre compressive failure in cross-ply single edge notch specimen, 190
through the thickness kink-band formation in cross-ply compact compression specimens, 187
numerical modelling, 191–5, 196–7
failure envelope generated by FE micromechanical models and kink band, 195
failure envelopes generated by FE micromechanical compared to experimental data, 196–7
fibre deflection during kink-band propagation, 194
micromechanical FE models, 192
sequence of events for fibre kinking from FE micromechanical models, 193
unidirectional plies, 184–203
failure modes in unidirectional composites in longitudinal compression, 184
fibre misalignment, 33
fibre-reinforced plastics
environmental induced failure, 393–440
chemical agents and degradation mechanisms, 395–414
environmental conditioning and testing, 414–25
future trends., 431–3
modelling and predictive analysis, 425–30
optimising chemical resistance and prevention of failure, 430–1
fibre scissoring, 153
fibre splitting, 187, 201
fibre wash, 40–1
fibre waviness, 33
fibre wrinkling, 33
filament wood composites, 303
finite element method (FEM), 209
fixed-time conditioning, 416–17
flammability, 79
flexural strength, 162–3
fluidised bed, 355–6
folding mode, 383
four-point end-notched flexure (4ENF), 115–16
fracture, 376–7
mode I fracture toughness of SMC-R, 377
fracture toughness testing
interlaminar fracture toughness testing, 111–17
ply-level fracture toughness testing, 119–25
polymer matrix composites, 110–26
ply-level fracture mechanisms from continuous fibre-reinforced composites, 111
standardised test methods for measurement of fracture toughness, 112
translaminar fracture toughness testing, 117–19
fragmentation mode, 383

G

GLARE (glass-aluminium-reinforced epoxy), 266
glass transition temperature, 428
global buckling, 89–94, 325
computed buckling load vs heating time for sandwich panel, 93
computed buckling load vs heating time for single skin panel, 92
Green-Lagrange strain, 100
ground-based damage, 246
gycolysis, 357

H

heat distortion temperature, 415
high-energy radiation, 413
honeycomb-sandwich structures, 239
hybrid composites, 265
hydrolysis, 356–7

I

Illinois Institute of Technology Research Institute (IITRI), 140
impact damage, 53
impact loads, 230
in-plane mechanical testing, 134–66
compression, 140–9, 150
assembled and disassembled Wyoming CLC jig, 143
Celanese and IITRI jigs schematic, 141
compression results for T300/914 CFRP, 147, 148
compression test results for T300/914
CFRP specimens waisted on all four surfaces, 149
compressive stress-strain curve, 146
disassembled compression jigs, 142
end-tab bonding arrangement for the reverse chamfer specimen, 145
failed compression specimens waisted on all four faces, 150
failure, 146–9
load introduction methods for compression tests, 140
parallel-sided compression specimen, 147
reverse chamfered specimen, 145
specimen configuration, 143–5
specimen configurations for ASTM D3410M, ICSTM and ASTM D695, 144
strain measurement, 145–6
stress-strain curve for T300/914 CFRP, 149
types of test, 140–3
various compression jigs to the same scale, 141
flexure, 161–6
failure modes, 165–6
four-point flexure arrangement, 163
recommended specimen dimensions, 164
schematic of possible failure modes, 165
specimen dimensions and testing arrangement, 164–5
three-point flexure arrangement, 162
variation of normal stress and shear stress in flexure test, 163
shear, 149–61
ASTM V-notched beam shear jig with specimen, 155
failure modes for the V-notched beam test, 157
hoop-wound thin-walled cylindrical specimen, 151
schematic of 10 ° off-axis specimen, 154
schematic of the ±45 ° tensile specimen, 152
shear stress-strain curve for the ±45 ° specimen, 153
shear stress vs deflection for UD specimen, 158
three-rail shear jig and specimen, 159
torsion of a thin-walled tube, 149–52
two- and three-rail shear tests, 158–60
two-rail shear jig and specimen, 159
uniaxial tension of a ±45 ° laminate, 152–3
uniaxial tension of a 10 ° off-axis laminate, 154
V-notched beam (Iosipescu) shear test method, 155–8
V-notched beam specimen, 155
V-notched rail shear, 160–1
V-notched rail shear test specimen, 161
tension, 135–9
data reduction, 138–9
failure, 139
grips and specimen alignment, 135–6
principal directions and stress components for an orthotropic material, 135
specimen for checking testing machine alignment, 136
specimens, 136–8
strain measurement, 138
tensile specimen for 0 ° and 90 ° aligned reinforcement, 137
tensile specimens for non-0 ° reinforcement, 137
tensile stress-strain plot for UD T300/914, 139
in-service conditions, 370–1
inclined waisted shear specimen (IWS), 171–2, 173
indentation damage, 54
interlaminar fracture, 110
interlaminar fracture toughness testing, 111–17
mixed mode I/II testing, 116–17
mixed mode bending, 116–17
MMB specimen configuration, 117
mode I testing, 112–14
determination of correction factor for modified beam theory, 114
determination of m for critical strain energy release rate, 114
double cantilever beam, 112–14
double cantilever beam specimen, 113
mode II testing, 114–16
ELS specimen configuration, 115
end-loaded split, 114–15
4ENF specimen configuration, 116
four-point end-notched flexure, 115–16
International Standards Organisation (ISO), 130, 395
intralaminar fracture, 110–11
Iosipescu test, 160, 169, 170
ISO 62, 417
ISO 178, 164
ISO 14125, 164
ISO 14126, 140
ISO 14129, 152
ISO 20340, 424
ISO 12215 standard, 306
isolated bundles, 216
isophthalic neo-pentyl glycol (NPG), 398

J

J-integral, 105

K

Kevlar 49, 241, 401
kink-band formation, 184
kinking theory, 197

L

laminate material testing, 306
laminate theory, 93
LaRC05, 210
fibre kinking criterion, 201
LaRC matrix failure criterion, 198
large-scale bridging (LSB), 120
‘Lightning Protection of Structure’, 234
lightning strike, 234–7
Lockheed L-1011, 230
LS-DYNA, 387

M

macro-scale models, 208
‘make and test’ philosophy, 3
manufacturing defects
approaches to minimise impact, 46–9
controlling out defects, 47–8
designing out ‘defects’, 46–7
honeycomb core sandwich panel inspection, 49
in-process inspection, 48–9
avoidable defects in continuous fibre composites, 39–41
fibre wrinkling in corner of an autoclave moulded prepreg part, 41
gross fibre misalignment caused by mould loading forces, 40
gross fibre misalignment generated by minor lay-up error, 40
one potential lay-up defect generation mechanism, 39
out-of-plane fibre waviness caused by RTM preform manufacture process, 40
basic requirements, 26–7
cause of failure in polymer matrix composites, 26–51
future trends, 49–51
design of reinforcements and matrices that are less pronesensitive to defects, 49–50
managing variability in materials and processing, 50–1
impact of fibre misalignment defects on strength, 41–6
failed sample showing multiple delaminations, 44
failure initiation under transverse tension of defective corner moulding, 45
impact of defects on flexural strength, 42
misorientation of the plies in test samples, 43
ply wrinkling in test samples, 44
misaligned, wavy and wrinkled reinforcements, 33–46
avoidable defects in continuous fibres composites, 35
parts of complex geometry with no obvious fibre direction datum, 34
unavoidable factors in continuous fibre composites, 34–5
residual stresses and geometrical distortions, 29–31
thermally induced resin cracking in 3D woven block of composite, 31
sources of variability and defects in composite mouldings, 27–9
materials, 27–8
moulding processes, 28–9
unavoidable factors, 35–9
fibre waviness in prepreg, 36
impact of woven cloth drape on tow geometry, 38
tow edge shapes in a tow steered laminate, 38
variability in fibre direction, 37
voidage and delaminations on in-plane and out-of-plane properties, 32–3
loading rig to generate a transverse tensile stress in a corner region, 33
marine structures
failure of composite materials for surface vessels, 306–22
laminate material testing, 306
sandwich core behaviour, 306–8
structural tests, 308–22
failure of composite materials for underwater structures, 322–32
filament wound materials, 323–6
influence of impact on cylinder failure modes, 326–32
material types, 303–5
common marine composites, 304–5
polymer matrix composites failure
composite failures on racing yachts, 301
data from measurements of strains on multi-hull foil, 302
future trends, 333
modelling failure, 333
polymer matrix composites failure, 300–33
matrix microcracking, 191
McCartney’s theory, 17
mechanical impedance analysis (MIA), 287
mechanical recycling, 342–52
thermoplastic matrix composites, 345–52
effect of recycling and glass fibre length, 352
effects of reprocessing on polymer, reinforcement and other additives, 350
experimental variables in PET mechanical recycling research, 349
possible changes on polymer component, 346
properties of 30% GF PA66, 351
variables in recycling, 347
thermoset matrix composites, 342–5
flexural properties of recycling of SMC to BMC, 343
weight percentages of glass, filler and resin fractions, 344
mechanical testing
biaxial in-plane testing, 172–5
biaxial in-plane Arcan test, 175
cruciform specimens, 174
off-axis specimens, 174–5
tubular specimens, 172–4
in-plane testing, 134–66
compression, 140–9
flexure, 161–6
shear, 149–61
tension, 135–9
key issues, 130–4
end-tab arrangement on test material subpanel, 131
fibre volume fraction, 132
pre-test records, 134
size effects, 134
specimen alignment, 132–3
specimen conditioning, 132
specimen preparation, 130–2
strain measurement, 133–4
stress state, 132
out-of-plane testing, 166–72
shear testing, 169–72
tension and compression testing, 166–9
polymer matrix composites strength and stiffness testing, 129–77
triaxial testing, 175–6
constrained out-of-plane compression, 176
cruciform specimens, 175–6
meso-scale models, 208
microbuckling theory, 196
micromechanics models
MiG-29 composite vertical stabiliser inspection, 290
MIL-STD-464, 234
military applications
ballistic testing of blades under tension load, 283–5
blade after hit (inlet hole), 285
blade after hit (outlet hole), 285
second stage of experiment, 283
ballistic testing of blades without any tension applied, 281–3
blade after test, 282
change in bullet velocity after spar penetration, 283
outlet hole – roving penetration, 282
implications for preventing failure, 285, 287–93
data processing, 288–9
examples of data processing, 289–93
flaw size comparison in the disbond area for F-16 jet fighter, 292
flaw size comparison in the disbond area for MiG-29, 293
image processing of composite horizontal stabiliser inspection results, 292
image processing of MIA inspection results, 291
image processing of MiG-29 composite vertical stabiliser inspection results, 294
stress distribution in the bondline, 287
polymer matrix composites failure, 279–98
ballistic damage, 280–5
tests of residual strength and residual stiffness, 284, 286
final damage in residual strength test, 286
stiffness of the blades before and after the test, 286
trends in modelling composite failures, 293, 295–8
node shaking, 297
randomisation of material properties, 296–7
stacked shell, 297–8
mixed mode bending (MMB), 116–17
mixture rule, 82
MLT model, 387–8
modified beam theory, 113
moisture, 237–41
moisture degradation, 395–401
glass transition temperature of epoxy resin, 397
osmotic blistering of GRP boat hull, 398
SEM image of poor and good adhesion between fibre and matrix, 396
tensile properties of hot/wet conditioned [02/902]S cross-ply laminates, 400
tensile properties of hot/wet conditioned unidirectional laminates, 400

N

NASA Composite Wing Program, 259
National Business Aviation Association (NBAA), 247
natural composites, 359–61
node shaking, 297
Nomex honeycombs, 314
nominal stress tensor, 296
nonwoven carbon tissues (NWCT), 251
normalised energy release rate, 124

O

osmosis blistering, 398
out-of-plane mechanical testing, 166–72
shear testing, 169–72
Arcan jig, 172, 173
double notch compression test, 170–1
inclined waisted shear specimen, 171–2, 173
Iosipescu test, 169, 170
IWS specimen and jig arrangement, 173
schematic of double notch compression test, 171
schematic of inclined waisted shear specimen, 172
schematic of short beam shear test, 171
shear stress components and specimen configurations, 170
short beam shear test, 169
tension and compression testing, 166–9
axial loading, 166–7
flexural loading, 167–9
interlaminar tensile test in flexure, 168
interlaminar tensile tests, 168
loading jig for tension testing throughthickness specimens, 167
through-thickness flexure specimen, 168
through-thickness tension and compression, 166

P

Pareto approach, 259
Paris power law, 379
photo-oxidation, 411–13
picture frame tests, 308
Piola–Kirchhoff stress, 100
plastic micro-buckling, 98–102
axial load vs axial displacement, 101
micromechanical deformation kinematics based on crystal plasticity theory, 99
resolved shear stress on slip system vs fire-heating time, 101
plastic waste disposal, 341
plastics recycling, 338
ply drops, 45
ply-level fracture toughness testing, 119–25
fibre dominated failure modes, 122–6
compact compression, 124–5
compact compression specimen, 125
compact tension, 122–4
compact tension specimen, 123
four-point bend, 125–6
four-point bend specimen, 126
mode I fibre compressive failure, 124–6
mode I fibre tensile failure, 122–4
matrix dominated failure modes, 119–22
DCB loaded with pure moments, 120–1
four-point bend, 121–2
four-point bend specimen, 122
mode I longitudinal intralaminar matrix failure, 120–1
mode I transverse intralaminar matrix failure, 121–2
unidirectional DCB specimen loaded with pure moments, 120
Polish Air Force Institute of Technology, 281
polymer matrix composite
failure in automotive and transport applications, 368–90
automotive and road transportation applications, 369
common in-service conditions causing failure, 370–1
composites for crashworthy structures, 382–8
future trends, 389–90
implications of preventing failure, 388–9
sheet moulding compound composites, 371–82
failure in defence applications, 279–98
ballistic damage, 280–5
implications for preventing failure, 285–93
trends in modelling composite failures in military applications, 293–8
failure in marine and offshore applications, 300–33
future trends, 333
material types, 303–5
modelling failure, 333
surface vessels, 306–22
underwater structures, 322–32
failure mechanisms considerations in design of aerospace structures, 227–71
design considerations, 229
designing for damage in composites, 248
materials-based approaches, 248–55
structural considerations, 229–48
structures-based approaches, 255–66
fibre-dominated compressive failure, 183–219
physics of fibre kinking in unidirectional plies, 184–203
recycled composites, 213–18
two-dimensional woven composites, 203–12
low and medium velocity impact as a cause of failure, 53–74
computational models, 71–3
future trends, 73–4
impact damage, 54–7
impact response, 57–66
strength and stability after impact, 66–71
manufacturing defects as cause of failure, 26–51
approaches to minimise the impact of manufacturing defects, 46–9
future trends, 49–51
misaligned, wavy and wrinkled reinforcements, 33–46
residual stresses and geometrical distortions, 29–31
sources of variability and defects in composite mouldings, 27–9
voidage and delaminations, 32–3
progress in failure criteria, 3–22
aims of the first World-Wide Failure Exercise, 5–7
current activities, 17–22
description of available models, 9
design problems solved, 9–17
gaps identified, 17
setting up test problems, 7–9
recycling, 337–67
future strategies, 359–61
mechanical recycling, 342–52
plastic waste disposal, 341
problems of reuse, 340–1
properties of recovered fibres, 358–9
recovery, 339–40
recovery techniques, 352–8
recycled carbon fibre in fluffy form, 358
reuse, 339
strength and stiffness testing, 129–77
biaxial in-plane testing, 172–5
in-plane testing, 134–66
key issues, 130–4
out-of-plane testing, 166–72
triaxial testing, 175–6
structural integrity of panels in fire, 79–106
global buckling, 89–94
material behaviour at elevated temperature, 86–9
other aspects of structural integrity in fire, 102–6
plastic micro-buckling, 98–102
sandwich panels skin wrinkling, 94–8
temperature distribution, 81–6
toughness testing, 110–26
interlaminar fracture toughness testing, 111–17
ply-level fracture toughness testing, 119–25
translaminar fracture toughness testing, 117–19
printed circuit board (PCB), 131
progressive crushing, 387–8
progressive failure analysis, 296
PRSEUS, 263
pyrolysis, 354–5
example of polymer behaviour, 355
PZL W-3 Sokol blade, 281

Q

quasi-isotropic plate stiffness, 61

R

R-curve effects, 119
recovery, 339–40
processes for biomass, energy and materials, 340
recovery techniques, 352–8
chemical recycling, 353–6
depolymerisation technologies, 356–8
thermal conversion methods, 352–3
recycled composites, 213–18
short-fibre recycled composites, 213–16
compressive failure of short fibre rCFRPs with fibre bundles, 215
recycled composite with multiscale structure consisting of fibre bundles, 214
woven recycled composites, 216–18
mechanical response of woven rCFRP, 217
recycling, 339
decision tree, 338
future strategies, 359–61
comparison of properties, 360
filler and nanoparticulates, 361
natural composites, 359–61
self-reinforcing materials, 361
mechanical recycling, 342–52
properties of recovered fibres, 358–9
thermoplastic matrix composites, 345–52
thermoset matrix composites, 342–5
polymer matrix composites, 337–67
plastic waste disposal, 341
problems of reuse, 340–1
recovery, 339–40
reuse, 339
recovery techniques, 352–8
chemical recycling, 353–6
depolymerisation technologies, 356–8
thermal conversion methods, 352–3
reduced compact compression test set-up (rCC), 206
region of interest (RoI), 288
resin film infusion (RFI), 252
resin infusion under flexible tooling (RIFT), 131
resin transfer moulding (RTM), 252
reuse, 339
problems of reuse in polymer composites, 340–1

S

S-2 glass, 403
sandwich concept, 303
sandwich core behaviour, 306–8
sandwich panels skin wrinkling, 94–8
wrinkling model in combined thermal-mechanical condition, 95
wrinkling stress vs fire-heating time, 97
shear banding, 218
shear-driven fibre compressive failure, 187–9
shear loading, 140
sheet moulding compound, 342
sheet moulding compound composites, 371–82
effect of stress concentration, 375–6
damage formation in SMC-R plate, 376
environmental effects, 381–2
tensile strength of SMC-R, 382
fatigue, 377–80
fatigue strength of SMC-R composites, 378
modulus degradation during fatigue cycling, 379
S-N diagrams of SMC-R25 and SMC-R65, 378
fibre orientation, 371
fracture, 376–7
mode I fracture toughness of SMC-R, 377
impact, 380–1
damage on the back side of impacted SMC-R panel, 381
post-impact residual tensile properties, 380
properties of various composites, 372
tensile characteristics, 373–5
knit line formation, 374
SMC-R25 and SMC-R65 composites tensile stress-strain diagrams, 373
tensile strength variation, 375
Weibull parameters for strengths of SMC-R28 and SMC-R50, 375
short beam shear test, 169
signal processing, 293
signal-to-noise ratio (SNR), 289
simple trigonometric scaling, 240
skin wrinkling, 94
SMC-C20R30, 374–5
SMC-R25, 373
SMC-R50, 374
SMC-R65, 373
solvolysis, 356
spalling, 58
splaying mode, 383
spring-in, 30
stacked shell method, 297–8
stacking, 204
static fatigue, 407
static fatigue tests, 422
Stefan-Boltzmann constant, 83
stiffnesses, 129
strain energy release rate, 112
strain gauges, 133
structural fire integrity
global buckling, 89–94
computed buckling load vs heating time for sandwich panel, 93
computed buckling load vs heating time for single skin panel, 92
material behaviour at elevated temperature, 86–9
power form model of degradation with respect to temperature rise, 87
simplified power form model of degradation, 88
other aspects, 102–6
design of structural fire integrity, 105–6
failures induced by debonding, delamination and cracking, 104–5
plastic micro-buckling, 98–102
axial load vs axial displacement, 101
micromechanical deformation kinematics based on crystal plasticity theory, 99
resolved shear stress on slip system vs fire-heating time, 101
polymer matrix composite panels, 79–106
sandwich panels skin wrinkling, 94–8
wrinkling model in combined thermal-mechanical condition, 95
wrinkling stress vs fire-heating time, 97
temperature distribution, 81–6
temperature distribution and simplified temperature model for sandwich panels, 86
temperature-time response of the laminate, 84
thermal-mechanical model for composite panels, 82
thermal distortion, 102–4
influence of ratio of skin thickness to core thickness to non-dimensional curvature, 103
stress at the interface between unexposed skin and core, 104
supercritical water, 357
surface vessels
composite materials failure, 306–22
laminate material testing, 306
sandwich core behaviour, 306–8
shear tests on core materials, 307
structural tests, 308–22
assemblies, 314–16
boat drop test, 315
bonded stiffener assembly, 319
compression tests on high modulus composites, 322
drop weight impact, 313
hard impact, 310–13
hard impact damage, 313
in-plane shear, 308–10
in-plane shear test, 311
lateral pressure loading of panels, 308
medicine ball soft impact test, 316
PVC foam core shear failure in sandwich under lateral pressure loading, 310
sandwich in-plane shear failures, 312
sandwich soft impact failure modes, 318
simulation of mast loading, 317–22
soft impact, 314
soft impact on aluminium honeycomb core sandwich panel, 317
tests on laminate and sandwich panels under transverse pressure, 309
top hat pull-off at 1 m/s, 320–1
Z-pins insertion in overlaminated region, 320
syngas, 353
syntactic foams, 302, 304
failure, 329–32
properties, 329

T

‘T’ root section, 31
takeoff and landing loads, 230
tangent modulus method, 105
thermal ageing, 415–16
thermal conversion methods, 352–3
combustion, 352–3
thermal cycling, 397
thermal distortion, 102–4
influence of ratio of skin thickness to core thickness to non-dimensional curvature, 103
stress at the interface between unexposed skin and core, 104
thermal gravimetric analysis (TGA), 88, 416
thermal softening, 80
thermal spiking, 410–11
thermo-chemical recycling process, 213
thermo-oxidation, 410–11
SEM image of high temperature degraded woven CFRP laminate, 411
thermolysis, 354
thermoplastic interleaves, 251
thermoplastic matrix composites, 345–52
thermoset interleaves, 251
thermoset matrix composites, 342–5
translaminar fracture, 111
translaminar fracture toughness testing, 117–19
mode I, 117–19
eccentrically loaded single-edge-notch tension, 117–19
ECT recommended specimen dimensions, 118
typical load-displacement plot for ECT specimen, 119
triaxial testing, 175–6
constrained out-of-plane compression, 176
out-of-plane compression of constrained specimen, 176
cruciform specimens, 175–6
Twaron, 241
two-dimensional signal value evaluation, 293
two-dimensional woven composites
analytical modelling, 208, 209–10
description and comparison between analytical and experimental results, 209–10
compressive failure, 203–12
experimental observations, 203–7
detail of a tow failed by kinking in a twill specimen, 205
idealised laminate with different stacking configurations, 206
location of the failure relative to crimp region centre, 204
longitudinal compression of a 2 × 2 twill composite, 207
tows fail individually with significant out-of-plane movement, 205
numerical modelling, 209–12
finite element model used, 211

U

UCSD multi-axial fire test apparatus, 92
‘unambiguous manufacturing instruction sets’, 47
underwater structures
composite materials failure, 322–32
failure of filament wound materials, 323–6, 327
composite cylinders under hydrostatic pressure loading, 323
defects in carbon composite cylinders, 327
imploded glass and carbon reinforced composite tubes after pressure testing, 324
internal hoop strain measurements indicating Mode 2 buckling, 325, 326
local failure at tube end due to stress concentration, 324
influence of impact on cylinder failure modes, 326–32
change in implosion failure mode after impact, 328
failure of syntactic foams, 329–32
glass spheres used in syntactic foams, 330–1
impact damage in carbon/epoxy tube, 328
macrosphere syntactic foams, 331
mechanical response of syntactic foams under hydrostatic pressure loading, 332
syntactic foams properties, 329
UV radiation, 411–13

V

vacuum-assisted resin transfer moulding (VARTM), 252
Vant’Hoff equation, 425
Vectran, 241
velocity impact
cause of failure in polymer matrix composites, 53–74
issues of impact on composites, 54
computational models, 71–3
future trends, 73–4
impact damage, 54–7
damage types in impacted fibre reinforced laminates, 55
distribution of delaminations for a 48-ply and 16-ply laminate, 57
distribution through the thickness, 56
fibre damage in a 16-ply and 48-ply laminate, 57
impact response, 57–66
response and delaminations due to 10 J impact, 59
types, 57–9
wave phenomena and response types during impact, 58
large mass impact, 60–3, 64
delamination threshold load for various layups and plate geometries, 62
effect of fibre fracture on delamination size, 64
measured load and deflection histories during impact, 64
predicted and measured load vs deflection during impact, 63
structural model, 60
small mass impact, 64–6
structural model, 65
strength and stability after impact, 66–71
averaged apparent compressive stress-strain curves, 71
damage width and panel properties on buckling strain, 68
damage width and panel properties on panel buckling strain, 68
damage zones and variation of material properties at two impact energies, 70
experimental delamination size vs velocity and theory, 66
relation between local strains and local stiffness, 69
tensile stress-strain curves, 70
thickness and material on compressive strength after impact, 67
virtual crack closure technique (VCCT), 298
virtual testing, 177
voidage, 32

W

waisting, 147–8
Weibull distribution, 375
Whitney–Nuismer point-stress failure criterion, 376
Winkler model, 94, 96
World-Wide Failure Exercise (WWFE), 3–22
current activities, 17–22
second exercise, 18–20
third exercise, 20–2
description of available models, 9
World-Wide Failure Exercise (WWFE-1)
aims, 5–7
diagram showing the adopted process, 6
stage I: establishing a framework, 5
stage II: part A, 5
stage III: part B, 5–7
design problems solved, 9–17
brief description of the approaches of the originators of failure theories, 11–12
failure progression in glass/epoxy laminate under uniaxial tension, 15
list of major issues addressed in the exercise, 13
predictions of selected cases, 10, 12
summary of failure theories benchmarked in WWFE-1, 10
theoretical predictions of 19 failure criteria and test data for test case 3, 14
various failure models used in WWFE-1, 16
gaps identified, 17
list of major issues addressed in the exercise, 13
setting up test problems, 7–9
details of the laminates and loading (test) cases used in the first exercise, 7
lamina and laminate coordinates and loading configurations, 8
World-Wide Failure Exercise-2 (WWFE-2), 17, 18–20
aims, 18
list of participants and their methodology involved, 19
methodologies used, 19–20
test cases, 18–19
World-Wide Failure Exercise-3 (WWFE-3), 17, 20–2
aims, 20
details of test cases used, 21
methodologies used, 22
test cases, 20–1
wrinkling stress, 96

X

X-33 cryogenic tank, 238

Z

Z-pinned joints, 260–2
Z-pins, 260–1, 316
Zylon, 241