Carbon Fiber Parts Performance In Crash SITUATIONS · (Dynamic, LS-DYNA®) DESIGN OPTIMISATION...

© 2016 by Plasan 1

Carbon Fiber Parts

Performance In Crash

SITUATIONS -

CAN WE PREDICT IT?

Commercial Division of Plasan Sasa

© 2016 by Plasan 2 © 2016 by Plasan

ABOUT THE AUTHORS

D.Sc - Technion - Israel Institute of technology

Head of the simulation and survivability team, Plasan

Specialities:

High strain rate dynamic simulation- Crash, Blast, Penetration

FE Analysis, Discrete Element simulation, Multi body Simulations

Soil Dynamics

Mechanics of materials

Dr Zvika Asaf

PhD – Ben Gurion University of the Negev

Senior R&D engineer, Plasan

Dr Vadim Favorksy


World’s leading designer and supplier of lightweight composite/ metal-composite vehicle bodies

ABOUT PLASAN


ABOUT PLASAN

International company with R&D and manufacturing facilities in Israel, US, and France plus broader partner network

© 2016 by Plasan 5 Plasan Proprietary Information

THE PROBLEM

But what happens After failure? Crash – High rate dynamic phenomena – 10-100 milliseconds

Design with composite in elastic regime is well known and understood


PLASAN EXPERIENCE WITH HIGH RATE DYNAMIC – BLAST STRUCTURE INTERACTION

THE MODEL BLAST TEST

• A mine blast is essentially the same as a crash impact, just from underneath

• Hybrid III dummies • Simulation calibrated by physical testing


COMPOSITE MATERIALS IN MINE BLAST CONVERTING STEEL CAB TO COMPOSITE CAB

SIMULATION RESULTS WITH STEEL DEFLECTOR

E-glass Cab 260 kg Steel Cab 586 kg E-glass with Aluminium frame Cab 280 kg


E-GLASS MODEL CALIBRATION

Properties verification

MTS tension test

THE DESIGN

• Very different from behaviour of metals • Anisotropic material • Properties in one direction not necessarily

shared in others • Many variables (fibre, orientation, resin,

production process) • FE model at level of fibres • Interlaminar relationships • Modes of failure


LAMINATED COMPOSITE - FAILURE IN BENDING

The delamination process


E-GLASS BALSA-WOOD STRUCTURE

3-POINT BENDING, 100 MM/SEC

SIMULATION

CONTACT FORCE – COMPARISON

TEST


BLAST TEST RESULTS –COMPOSITE CABIN E-GLASS WITH ALUMINIUM FRAME CAB

POST BLAST


E-GLASS WITH BALSA CAB

POST BLAST

BLAST TEST RESULTS –COMPOSITE CABIN


MODELING LAMINATED COMPOSITE AGAINST BALLISTIC THREAT

TEST

PROJECTILE

SIMULATION

First shot Second shot

FRONT VIEW

cut_dynima.avi


CARBON COMPOSITES CRASH MODELING

Force

[kN]

Displacement [1E-3m]

Velocity [m/s]

Steady state forces -20000 N

Braking Forces -120000 N


THREE POINT BENDING DROP TEST

Force

[kN]

Middle Crack


Optimisation Parameters Tuning

Angles Optimisation

(Static, OptiStruct®)

Validation of the results

(Dynamic, LS-DYNA®)

DESIGN OPTIMISATION FLOWCHART

Problem

Definition

(Materials,

Manufacturing

Constraints

etc.)

Thickness

Optimisation


Validation of the results


No

Yes

Satisfying

results No

Fine Tuning


Satisfying

results Parameters

Tuning

No

Yes End

Yes

Topological

Optimisation


Satisfying

results

Optimisation

Parameters

Tuning


TOPOLOGICAL OPTIMISATION – THE MODEL

The Optimisation was performed with OptiStruct®


TOPOLOGICAL OPTIMISATION – LOAD CASES

Load Y

Fixed Boundary

Distributed Force

Load Y


TOPOLOGICAL OPTIMISATION – RESULTS


LAYUP AND ANGLE OPTIMISATION

The beam was divided into 13 regions (see the figure). Each region was built from 4 sub-plies having [0/45/90/-

45] lay-up – First Path

The optimisation variables in this stage were the thicknesses of the sub-plies (13*4 variables)

Visualisation of the Walls’

Thicknesses

30 26

11

2

3

6

4

5

12

10

7

9 27


OPTIMISATION FOR MANUFACTURING AND COST CONSTRAINTS

The beam was divided into 2 regions (see the figure). Each region was built from 4 sub-plies

Visualisation of the Walls’

Thicknesses

2

1


PLASAN MODEL AFTER OPTIMISATION – RESULTS

Material: UD Carbon

Mass: 8.0 kg (34% reduction)

Fmax ≈ 75 kN;

Ref. Fmax ≈ 47 kN;

Material: Aluminium

Mass: 11.2


COMPARISON BETWEEN DESIGNS

0

10

20

30

40

50

60

70

80

0 50 100 150 200

Reference Aluminum DesignCarbon Plasan

Ap

plie

d F

orc

e, kN

Displacement, mm

Energy Absorbed: Reference Aluminium (12.2kg): 6.3kJ Plasan Carbon (8.0kg): 10.2 kJ

© 2016 by Plasan 24 Plasan Proprietary Information © 2016 by Plasan

FULL COMPOSITE FRAME

© 2016 by Plasan 24

SCHEMATIC VIEW FOR ILLUSTRATIVE PURPOSES ONLY


OVERVIEW OF THE NUMERICAL MODEL

COMPOSITE BEAMS

ALUMINIUM CONNECTIONS

COMPOSITE SKINS


ROOF CRUSH – FMVSS 216

Local buckling: F = 8 [ton] @ 40mm Global buckling: F = 9 [ton] @ 60mm


SIDE POLE IMPACT - FMVSS 214

Side pole crash test is detailed in FMVSS 214. The car is moving at 20 MPH on a line passing through the driver head COG, at 75° from the longitudinal centreline. The crash is between the car and a rigid pole of Ø10”


RESULTS OF THE ANALYSIS

The frame absorbed the crash energy without penetration into the occupants volume


FRONTAL IMPACT - FEA VIDEO

Frontal Crash force


CONCLUSIONS

Potential 30% weight saving to aluminium

Basic design concepts must

be changed

FEA is part of design for cost

process

Composite crash is

predictable

Carbon Fiber Parts Performance In Crash SITUATIONS · (Dynamic, LS-DYNA®) DESIGN OPTIMISATION...

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