TThe Blast Load he Blast Load Response of Response of Honeycomb Sandwich Honeycomb Sandwich PanelsPanels

TThe Blast Load he Blast Load Response of Response of Honeycomb Sandwich Honeycomb Sandwich PanelsPanelsY. ChiY. Chi

Supervisors: Prof G. N. Nurick, Dr G. S. LangdonSupervisors: Prof G. N. Nurick, Dr G. S. Langdon

Blast Impact Survivability Research Unit (BISRU),Blast Impact Survivability Research Unit (BISRU),

University of Cape TownUniversity of Cape Town

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BackgroundBackground

• Passenger Aircraft SafetyLockerbie Plane Crash

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General Aim

In search of better In search of better protection against protection against blastblast

In search of better In search of better protection against protection against blastblast

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Specific Aims of This Study

• To determine the response of honeycomb sandwich panels to uniformly distributed air-blast loading.

• To investigate the effect of:• Core thickness

• Plate thickness

• Core material

• Core configuration

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Structure Under Investigation

Front face plate

Back face plate

Aluminium honeycomb core

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Presentation Structure

• Blast test configurationsVarious panel configurations have been proposed and tested

• Quasi-static testing on the componentsCharacterise the materials(mild steel plates and aluminium honeycombs)

• Blast testing on the sandwich panels

• Concluding remarks

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Experimental Setup

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Panel Configurations

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Dharmasena et al, 2007, in press

Background Knowledge

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Background Knowledge

Dharmasena et al, 2007, in press

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Honeycomb Material Characterisation

Jones, Structural impact

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Honeycomb Material Characterisation

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Background Knowledge

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Focus of Today

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Single-1.6: 1.6mm plate 29mm h/c

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Single-1.6: 1.6mm plate 29mm h/cFront plate deflection – 5.3Ns to 29.2Ns

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Mid-point deflection of the face plates and the honeycomb cores

Single-1.6: 1.6mm plate 29mm h/c

0

5

10

15

20

25

30

0 5 10 15 20 25 30 35 40 45 50

Impulse (Ns)

De

fle

cti

on

(m

m)

Single-1.6 Front Single-1.6 BackH/c Front surface H/c Back surfaceLinear (Single-1.6 Front) Linear (Single-1.6 Back)

Trendline of plate deflection Honeycomb

deflection

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Single-1.6: 1.6mm plate 29mm h/c

at the center

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Honeycomb Material Characterisation

Densification

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0

5

10

15

20

25

30

0 5 10 15 20 25 30 35 40 45 50

Impulse (Ns)

Cru

sh d

ista

nce

(m

m)

Honeycomb crush distance graph

Densification = 29.2Ns

Single-1.6: 1.6mm plate 29mm h/c

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Single-1.6: 1.6mm plate 29mm h/c

Back plate deflection – 5.3Ns to 36.8Ns

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11g

1.6mm

11g

1.0mm

Effect of Plate Thickness

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1.6mm vs 1.0mm Plate Thickness

0

5

10

15

20

25

30

0 5 10 15 20 25 30 35 40 45 50

Impulse (Ns)

De

fle

cti

on

(m

m)

Single-1.6 Front Single-1.6 BackSingle-1.0 Front Single-1.0 BackLinear (Single-1.6 Front) Linear (Single-1.6 Back)Linear (Single-1.0 Front) Linear (Single-1.0 Back)

Mid-point deflection of the face plates

Slide 24 © CSIR 2006 www.csir.co.za

1.6mm vs 1.0mm Plate Thickness

Honeycomb crush distance graph

0

5

10

15

20

25

30

0 5 10 15 20 25 30 35 40 45 50

Impulse (Ns)

Cru

sh d

ista

nce

(m

m)

Single-1.0 Single-1.6 Linear (Single-1.0) Linear (Single-1.6)

Densification

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Mid-point deflection of the face plates

1.6mm vs 1.0mm Plate Thickness

0

5

10

15

20

25

30

0 5 10 15 20 25 30 35 40 45 50

Impulse (Ns)

De

fle

cti

on

(m

m)

Single-1.6 Front Single-1.6 BackSingle-1.0 Front Single-1.0 BackLinear (Single-1.6 Front) Linear (Single-1.6 Back)Linear (Single-1.0 Front) Linear (Single-1.0 Back)

Densification Densification

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• For the effect of plate thickness:

A honeycomb sandwich panel with thinner face plates will have

higher front face plate deformation. This means the core will

densify at a lower impulse and transmit larger forces to the back

plate. This is generally undesirable.

• This, in conjunction with the effect of the core thickness, provides a detailed investigation of the response of honeycomb sandwich panels to blast loading.

• Further details will be available in my MSc thesis.

Concluding Remarks