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Bridge aeroelasticity simulation by using

ANSYS software

Gergely Szabó

Pont Terv Ltd.

Budapest, Hungary

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Bridge stuctures

• Bridge types

– Simple beam

– Truss

– Arc

– Suspension

– Cable supported

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Bridge structures

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Bridge structures

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Bridge structures

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Bridge structures

• Dynamic load types

– Vehicle

– Pedestrian

– Earthquake

– Wind

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Aeroelasticity

• Tacoma flutter

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Aeroelasticity

• 3D airplane instability

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Background

• Structural dynamics (CSD)

• Fluid dynamics (CFD)

• Fluid-structure interaction (FSI)

• Instabilities

– Flutter

– Divergence

– Galopping

– Vortex shedding

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Railway bridge

• FEM model of the bridge

• Load model

• Dynamic simulation

• Dynamic displacements

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Railway bridge

• Bridge structure

C ross section

5000/2=2500

C rossgirder

Ba llast bed

35

13

00

35

35

600

C able

M ain g irder540

Arc

S ide v iew

35

52000/2=26000

540

52000/4=13000

90

00

K

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Railway bridge

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Railway bridge

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Railway bridge

• 1st mode shape

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• Displacement, stress field

Railway bridge

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Railway bridge

• Rolling train

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Railway bridge

• Displacements

-0,05

-0,04

-0,03

-0,02

-0,01

0

0,01

0,02

0,03

0,04

0,05

0 50 100 150 200 250 300 350 400 450 500

Place of the first wheel [m]

UY

[m

]

v=15 m/s

v=30 m/s

v=45 m/s

v=60 m=s

v=90 m/s

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Oscillating flat plate

• Theodorsen flat plate theory

• Time dependent forces and moments

• Reduced velocities (Ured; U, omega, B)

• Flutter derivatives (H1-4, A1-4)

• CFD model

• Validation of the CFD simulation

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Oscillating flat plate

• CFD mesh

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Oscillating flat plate

• Comparison

-0,80

-0,60

-0,40

-0,20

0,00

0,20

0,40

0,60

0,80

0,00 0,05 0,10 0,15 0,20 0,25 0,30 0,35 0,40 0,45 0,50

t [s]

Fy

[N

]

Fy_inviscid

Fy_Reynolds

Fy_Theodorsen

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Bridge deck

• Bridge over the Tisza river

• Wind tunnel tests

• Forced vibration method

• CFD simulation

• Comparison

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Bridge deck

• CFD mesh

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Bridge deck

• Velocity contour

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Bridge deck

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Bridge deck

• Comparison

-0,20

-0,15

-0,10

-0,05

0,00

0,05

0,10

1,00 1,10 1,20 1,30 1,40 1,50 1,60 1,70 1,80 1,90 2,00

t [s]

M [

Nm

]

FLUENT

MEASUREMENT

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3D aeroelastic bridge model

• Full aeroelastic wind tunnel model

• FEM approximation for the mechanics

• Rough mesh for the fluid flow

• Simple turbulence model

• Coupling of the fields

• Comparison

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3D aeroelastic bridge model

• FEM approximation

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3D aeroelastic bridge model

• Dynamic mode shapes of the bridge

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3D aeroelastic bridge model

• CFD mesh

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3D aeroelastic bridge model

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3D aeroelastic bridge model

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3D aeroelastic bridge model

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Objectives

• Full aeroelastic wind tunnel model

• Measurements

• Critical wind speed

• More detailed CFD and CSD models

• Validation

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Thank you for your attention!