High Temperature Material Laws of High Strength (S460) Steelfire-research.group.shef.ac.uk/steelinfire/downloads/... · 2007. 12. 22. · Fire load „Airplane“- Paintshop according

Institute for Steel Structures and Fracture MechanicsInstitute for Steel Structures and Fracture Mechanics

High Temperature Material Laws of High Strength (S460) Steel

Prof. Dr.-Ing. Jörg LangeInstitute for Steel Structures

and Fracture MechanicsTechnische Universität Darmstadt

STAHLBAU

STAHLBAU



7,8

8,2

15,0 15,0 15,0 15,0

Penthouse

1981

BMW AG in Berlin


60,0

15,0

7,5 7,5 7,5 7,5 7,5 7,5 7,5 7,5 7,5 7,5 7,5 7,5 7,5 7,5 7,5 7,5

120,0

Tensile forces H resulting from sagging composite beams

Protected beams carrying compressive forces15,0

15,0

15,0

1,2

5

2,5

2,5

2,5

2,5

2,5

B

B

1,2

5

Unprotected beams sagging under fire

H H

Protected beams

Protected beams

Beams and girders “level above ground floor“

AA



Paint shop for Airbus A380 – Hamburg 2004


Frame of the main door

Door Airplane


Deflections under self weight and fire

Am/V mostly less than 30


Fire load „Airplane“- Paintshop according to DIN 18230-1 (May 1998)

Fire load for one A380 – painting area

Kind of fire load: Mass

(KG) m - Factor Heating value

(kWh/kg) Energy

contents (kWh)

Airplane – primary structure 153.000 1 8,63 1.320.390

Hydraulic Oil 1.400 1 9,8 13.720

Tires 1.100 1 12,2 13.420

Chairs 17.000 1 7,686 130.660

Additional plastic 39.200 1 12,2 478.240

Additional load inside building 7.900 1 10,0 79.000

Kerosine (after emptying) 400 1 11,7 4.680

Paint 600 1 9,0 5.400

Tools etc. 12.500 1 8,0 100.000 Sum 2.145.510

This results in a specific fire load qr = 273,4 kWh/m2, in an area of 7.848 m2.

= 17 kg/m² wood



Reduction of the yield strength of S460

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

0 100 200 300 400 500 600 700 800 900 1000

Θ [°C]

f y(Θ

) / f y(20°C) [-]

SFB 148 (1986): StE 47

Winter (1990): StE 460 TM

Arbed (1989): StE 460 TM

Outinen (2000): S460 M

EC3-1-2


Chemical composition

Fine grain built due to Nb, Ti, V

S460 N:

Final rolling at 900°C

S460 M:

Final rolling at 800°CAustenite cannot re-crystallize due to Niob

⇒ fine grain ferrite

⇒ reduction of carbon


S460 N

S460 M

Equal grain size(G = 8)

S460 N:Round grain, linear distribution of perlite (dark)

S460 M:Uneven distribution,Distorted grainless perlite (less carbon)


Test methods

σ

ε

εs

Θ= const

F

F

Steady State Tests(+ creep):

Θ = const.εs, εk, εth separated


σ

ε

εsεs + εk

Θ= const

F

F

Test methods




σ

ε

εsεs + εk

Θ

F = const

FΘ= const

F

F

Test methods

Transient State TestsΘ ≠ const

εs, εk and εth included




σ

ε

εsεs + εk

ε– εth = εs + εk

Θ

F = const

FΘ= const

F

F

Transient State TestsΘ ≠ const.

εs, εk and εth included



Test methods


S460N - direkter Vergleich stationär-instationär

0

50

100

150

200

250

300

350

400

450

500

0 0,5 1 1,5 2 2,5 3

Dehnung [%]

Sp

an

nu

ng

[N

/mm

²]

500°

600°

700°

800°

500-stat

600-stat

700-stat

800-stat

Comparison steady state tests – transient state test


Curve fitting using a nonlinear function

according to Anderberg (1983) and Rubert/Schaumann (1985)

fy,Θ

fp,Θ - c

εp,Θ εy,Θ εy,Θ + d

E0,Θ

EV,Θ

fp,Θ

d

a

b

c

εεεε

σσσσ

Ellipse:

cf)d(aa

bΘ,p

2Θ,y

2 −+ε−+ε−=σ


Analytical Stress-Strain-Relationship

Fitting of parameters

according to least square

method

λδ

δε−ε+ψ=

ΘΘΘΘ )()EE(a

,p,y,V,0

λδ

λ−+−ψ=

ΘΘΘΘ )ff()EE(b

,p,y,V,0

δ

−+−ε−ε−=

ΘΘΘΘΘΘΘ2

,p,y,p,y,p,y,V )ff()ff()(Ec

λ

ε−ε−−ε−ε=

ΘΘΘΘΘΘΘΘΘ2

,p,y,0,V,p,y,p,y,V )(EE)ff()(Ed

Hilfswerte )f;f;;;E;E(f,, ,p,y,p,y,V,0 ΘΘΘΘΘΘ εε=ψλδ

mit ΘΘΘ =ε ,0,p,p E/f

Θε≤ε ,p : Θε=σ ,0E

ΘΘ ε≤ε<ε ,y,p : cf)d(aa

b,p

2,y

2 −+ε−+ε−=σ ΘΘ

03,0,y ≤ε<ε Θ : ΘΘΘ ε−ε+=σ ,V,y,y E)(f

Geometry of the ellipse:


Examples for curve fitting

0

100

200

300

400

500

600

0 0,005 0,01 0,015 0,02 0,025 0,03

Dehnung [-]

Sp

an

nu

ng

[N

/mm

2]

200°C

500°C

700°C

mit Berücksichtigung

des Fließplateaus

S460 N


Analytical Stress-Strain-Curve for S460 N

0

50

100

150

200

250

300

350

400

450

500

0 0,005 0,01 0,015 0,02 0,025 0,03

Dehnung [-]

Sp

an

nu

ng

[N

/mm

2] 200°C

100°C

400°C

500°C

600°C

700°C

800°C900°C

300°C


0

50

100

150

200

250

300

350

400

450

500

0 0,005 0,01 0,015 0,02 0,025 0,03

Dehnung [-]

Sp

an

nu

ng

[N

/mm

2]

600°C

700°C

800°C

900°C

500°C400°C100°C

200°C 300°C

Analytical Stress-Strain-Curve for S460 M


Comparison of examples for S460 N und S460 M

0

50

100

150

200

250

300

350

400

450

500

0 0,005 0,01 0,015 0,02 0,025 0,03

Dehnung [-]

Sp

an

nu

ng

[N

/mm

2] 500°C

600°C

800°C

S460 NS460 MEC3-1-2


Comparison of results for S460 N und S460 M

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

1,1

0 100 200 300 400 500 600 700 800 900

Temperatur [°C]

Rt2

,0 /

fy(2

0°C

) [-

]

S460 N

S460 M

EC3-1-2

• increased strength of S460 M compared to S460 N

(yielding at higher temperatures)


Comparison to EC3-1-2

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

1,1

0 100 200 300 400 500 600 700 800 900

Temperatur [°C]

Rt2

,0 /

fy(2

0°C

) [-

]

S460 N

S460 M

EC3-1-2

• EC3-1-2 overestimates the S460 N

⇒ Will this lead to unsafe structures?


Ultimate Load Design

Calculation of the ultimate load at various temperatures and various slendernesses.Comparison of the new model to EC3-1-2

w0

N N

q0

V0

L = s

K

Θ Θ

w0= L/1000

q0 = 8 N w0 / L2

V0 = 4 N w0 / L

Nb,fi,Θ,Rk = ?


0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

0 20 40 60 80 100 120 140

λ = L/iy

κfi (

be

z.

au

f N

fi,8

00

°C,R

k,E

C3)

eigenes Werkstoffmodell - S460 N

Werkstoffmodell nach EC3-1-2

y

z

y

z

Calculation of Ultimate Load

800°C – Buckling perpendicular to y-axis (HEA 300)


Summary

• Higher strength of S460 M compared to S460 N

at 400°C ≤ Θ ≤ 900°C.

• Material laws according to EC3-1-2 are ok for

S460 M but not for S460 N.

Documents

High Temperature Material Laws of High Strength (S460) Steelfire-research.group.shef.ac.uk/steelinfire/downloads/... · 2007. 12. 22. · Fire load „Airplane“- Paintshop according