Composite Design for Armoured Fighting Vehicles

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Aldous Wilson
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1 Composite Design for Armoured Fighting Vehicles A presentation to IOM 3 18 th March 2008 Dr Mark French QinetiQ Project Manager mafrench@qinetiq.com

Armour and Structural Design Research Areas of specialist

metallics Predictive performance and mobility analysis

and soft soil modelling Human and user interface Noise &

2 Armour and Structural Design Research Areas of specialist expert knowledge include: Structural design Composites and metallics Predictive performance and mobility analysis Dynamic structural analysis Ballistic and blast analysis Tyre and soft soil modelling Human and user interface Noise & Vibration modelling Lightweight solutions Composite and transparent armour 2

3 How can weight savings be achieved in vehicles 3 Retain the same capability with a lighter force Protection Volume Performance Cost signature Lower weight Composite materials Improved design 3

Permission from Jane's Information Group Handheld HEAT RPG-7 Basic round: 300mm

4 Key threat requirements for lightweight vehicles KPV 14.5mm HMG Standard round penetrates 38mm of steel at 100 m range Reproduced with Permission from Jane's Information Group Handheld HEAT RPG-7 Basic round: 300mm steel Advanced round: 700mm of steel 1.4m reinforced concrete 2m logs and earth RPG-29 tandem warhead 4

5 Improvised explosive devices IED threats 5

6 Improvised explosive devices IED threats 6

be hit Don t be penetrated Mitigate damage Metal hull

7 Survivability onion spall liner = composite structure Don t be there Don t be seen Don t be targeted Don t be hit Don t be penetrated Mitigate damage Metal hull Spall liner Spall cloud Photo: Copyright B J James 7

8 Composite Spall Liner (or Composite Hull) Point of weapon penetration I ArmourHull Spall Shield Armour Hull A composite hull eliminates the need for a separate spall liner - reducing weight Metallic Hull Armour System Composite Hull Armour System 8

9 Hull material options weight efficiency Material Ballistic function Structural function Spall mitigation Ferrous alloys Non-ferrous alloy Glass composites Polymer fibre composites Carbon fibre composites Medium Medium Low High High Low Medium Medium High High Medium High Medium High Medium Aim is to integrate materials into an optimised solution using modelling tools! 9

10 Identify the structural requirement 10

11 Design tools- Dynamic models for structural design & mobility ADAMS model Tyre soil model ACAVP vehicle Dynamic modelling to identify load cases Optimisation of individual components such as suspension Mobility prediction over varying terrains ADAMS model Provides vibration performance assessment ADAMS model suspension 11

12 Why use carbon fibre composites compared to baseline steel Increased Material properties mechanical relative properties to the same for mass same of weight steel compared to E-glass, S2- glass, steel and aluminium Relative performance Bending stiffness Bending strength In plane stiffness In plane strength Steel Titanium Aluminium CFRP S2-glass QI E-glass QI CFRP 28x bending stiffness for the same weight of steel CFRP 10x bending strength for the same weight of steel A CFRP panel of the same mass as steel is 5 times the thickness Bending stiffness related to thickness cubed 12

13 Composite design - hull structure and components Mass optimisation of AFV hull to minimise structural mass Composite demonstrators Composite suspension arm 13

FEA Structural model optimisation 14 Standard FE model Define all loadcases Knife edge, 10G drop, racking, impact, track shear (Magnitudes derived from ADAMS )

14 FEA Structural model optimisation 14 Standard FE model Define all loadcases Knife edge, 10G drop, racking, impact, track shear (Magnitudes derived from ADAMS ) Apply constraints of minimum and maximum wall thickness E.g. surfaces can be specified for ballistic requirement Define targets of strength, stiffness and mass 14

Frontal impact / 10G vertical 2G knife edge 2G racking

15 Structural optimisation Identification material thickness MATERIAL THICKNESS 10G drop / turret mass 10G drop Frontal impact / 10G vertical 2G knife edge 2G racking Structure optimised to satisfy all loads in single analysis run 15

16 The CAFV EUROPA Consortium A consortium has 6 nations and contains 16 leading defence primes and technology suppliers Programme prime aim - Design guidelines WEAG for military platforms of CFRP UK Lead Industrial Company QinetiQ plc UK subcontracts BAES & VT Denmark RISO France Thales Italy Otomelara Netherlands TNO Norway FFI Sub-contract Sub-contract Sub-contract Sub-contract Sub-contract 16

17 EUROPA Application cases Den RISO PA6 Tenax-12k HTS %vf Norway (sides and roof section, BV206) Italy OTO MALARA - GG630T-DT epoxy T700 FFI Compare thermoplastic versus thermosets FFI (side/corner section of an AFV) Sandwich CFRP thickness 5mm (skins) and 40mm total Tenax UTS k / LY3505/xb3403 epoxy 17

French application case Suspension/floor Over

support Left assembled crossbar sheath Assembled

torsion bar flange Zoltek P35 / LY 564 22962

18 French application case Suspension/floor Over mould metallic suspension mounts Left bearing support Left assembled crossbar sheath Assembled crossbar Panhard Torsion bar flange support Right torsion bar flange Zoltek P35 / LY epoxy DET/CEP Application: VBL torsion bar anchoring supports 18

19 UK Manufacture and mechanical testing 3D Tufting Needle Thread Laid-up plies UK investigating hybrid carbon, E & S2 glass Loops 19

20 Fibre composite ballistic - mechanism Number of energy absorbing mechanisms (composite different to bare fabric ) Shear Tensile Back Crushing Front Fibre failure surfaces 20

(optional) Allows projectile pieces to turn and/or separate Composite Absorber Absorbs

21 An armour system mechanism Hard outer layer breaks or deflects round prior to striking composite Disrupter Slows, breaks, deforms, erodes, and/or turns projectile Spacer (optional) Allows projectile pieces to turn and/or separate Composite Absorber Absorbs residual fragments, energy Use combination of testing with modelling to define optimised armour configuration 21

22 Commercial vehicle testing with optimisation via modelling Ballistic impact into armoured glass using Autodyn Ballistic impact and blast testing 22

Mine blast small and large scale testing Plate 2m by 2m explosive Test rig 800 by 800 panels Panel L2A1 detonator (tip located at charge centroid) PE4 Charge Polystyrene mounting M20-300 mm shank

23 Mine blast small and large scale testing Plate 2m by 2m explosive Test rig 800 by 800 panels Panel L2A1 detonator (tip located at charge centroid) PE4 Charge Polystyrene mounting M mm shank bolt Top frame Stiffener Crush block and mounting Pendine block Table frame (120 x 120 x 15mm mild steel-equal angle) Develop blast modelling of composites using small and large scale testing Trial representation lower hull floor to validate modelling Side View Steel beam section 23

24 Comparison of S2, steel and E glass failures 24

Blast modelling identification of failure Small scale testing must be arranged to

distance between the explosive charge and the panel to reproduce the loading from a

$Modelling of composite to identify loading to cause delamination and fibre fracture$

25 Blast modelling identification of failure Small scale testing must be arranged to try to reproduce large scale testing conditions Modelling used to identify the distance between the explosive charge and the panel to reproduce the loading from a mine placed below the bottom of a vehicle. Modelling of composite to identify loading to cause delamination and fibre fracture explosive explosive Delamination Fracture Fibre fracture through the laminate was identified as failure i.e no longer gas tight 25

26 Modelling : Predicting Delamination Solid Elements: Quarter Symmetry Model 40µs 50µs 60µs Stress wave induced delamination Deflection induced delamination 1ms 26

Mine blast modelling Integration of ADAMS,

loading on hull floor Vehicle-scale mine

flush mine / steel pot (generate vehicle

identify spine load and predicted injury

27 Mine blast modelling Integration of ADAMS, AUTODYN & LS-DYNA Generation of dynamic loading on hull floor Vehicle-scale mine blast response of plate equivalent to a flush mine / steel pot (generate vehicle acceleration data) Occupant accelerations to identify spine load and predicted injury Vehicle mine blast response (generate seat acceleration data) 27

28 Conclusion Programmes such as Europa have provided detailed information on the value of composites including carbon fibre composites (CFC) for armoured vehicles Testing to date has demonstrated that composites have great potential to reduce the weight of future vehicles Good design tools are essential to optimise performance against design criteria, structural, ballistic and blast 28 Future AFVs will need to be mix of materials to maximise system performance 28

29 Latest armour testing & UK low-cost concept video Thank you Questions 29

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