Learning Forum

[n66134267]

When simulating an RC blast door using SALE (ALE–FSI) in LS-DYNA,

the time-history trend of the door deflection matches the literature, but the peak displacement is significantly smaller.

	Peak deflection
Literature	3.47 mm
My model	< 2.0 mm

So the response shape is correct, but the amplitude is underestimated.

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Model summary

Geometry

• RC door thickness: 100 mm

• Door location: z = 0–0.1 m

• ALE domain: z = -0.6–3.4 m

• Door rear surface initially touching the frame

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Explosive

• TNT: 0.15 kg

• Half model with symmetry plane at x = 0

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ALE mesh

10 mm

 

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Concrete

MAT_072R3 (KCC)
f'c ≈ 19.7 MPa

 

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Reinforcement

 

MAT_PLASTIC_KINEMATIC
E = 200 GPa
ETAN = 1e9 Pa

Embedded using: CONSTRAINED_BEAM_IN_SOLID_PENALTY

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Solid elements

ELFORM = 1

 

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FSI coupling

 

ALE_STRUCTURED_FSI
LSTRSID = 1
(part set includes parts 1,2,3,4,5,11)
PFAC = 1
FLIP = 0

 

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Contact

Door–frame interaction:

 

CONTACT_AUTOMATIC_SURFACE_TO_SURFACE

 

Frame is located behind the door and initially touching the door rear surface.

Friction:

FS = 0.2
FD = 0.15

 

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Tests already performed

ALE backside domain

 

z = -0.6 → -0.3

 

No noticeable effect.

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Beam–solid coupling parameters

Adjusted penalty parameters → no noticeable effect

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Frame-wall connection

Removing shared nodes → response trend became worse

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Question

In ALE–FSI blast simulations, when:

• pressure history appears reasonable

• displacement time-history trend matches literature

• but peak displacement is underestimated

what are the most common causes?

In particular, I would like to ask:

Could the door–frame initial contact (rear surface initially touching the frame) act as an early support condition and reduce the door bending deformation?

Any suggestions or similar experiences would be greatly appreciated.

[Nanda]

Hello User,

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Regards,

Nanda.

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[ErKo]

 

Hi

Perhaps DChen has some feedback?

Alsos perhaps contact the authors of this paper (Dynamic response of blast doors enhanced by enclosed-space...) to get more info on the FE model they did.

All the best

Erko