asif usmani school of engineering, university of edinburgh with...
TRANSCRIPT
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Developing for Modelling Structures in Fire
Asif Usmani
School of Engineering, University of Edinburgh
with thanks to,Jian Zhang, Jian Jiang, Yaqiang Jiang and Panagiotis Kot sovinos
Steel in Fire forum, 12 April 2011
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Why OpenSees?
♦ Difficult to continuously maintain, update and re-use research codes
♦ Commercial software expensive and restricted
♦ OpenSees is free, and
– a good platform to test ideas and make implementations available
– uses modern programming paradigms with greater granularity
– excellent structural/geotechnical analysis capabilities developing all the time
– HPC version
– excellent wiki with lots of help for users including many example scripts
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OpenSees Abstractions
DomainModelBuilder Analysis
Recorder
Constructs the objects in the model and adds them to the domain.
Monitors user defined parameters in the model during the analysis
Moves the model from state at time tto state at time t + ∆∆∆∆t
Holds the state of the model at time t and (t + ∆∆∆∆t)i
Source: Frank McKenna (PEER/UC Berkeley)
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Domain
Domain
Element Node TimeSeriesMP_Constraint SP_Constraint LoadPattern
ElementalLoad NodalLoad SP_ConstraintTrussZeroLengthElasticBeamColumnNonlinearBeamColumn(force, displacement)BeamWithHingesQuad(std, bbar, enhanced, u-p)ShellBrick(std, bbar, 20node, u-p, u-p-U)JointGenericClientExperimentalElement
ConstantLinearRectangularSinePath
Source: Frank McKenna (PEER/UC Berkeley)
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Material
Source: Frank McKenna (PEER/UC Berkeley)
Material
UniaxialMaterial nDMaterial section
ElasticElasticPPHardeningConcreteSteelHystereticPY-TZ-QZParallelSeriesGapFatigueMaterial
ElasticJ2TemplateElasto-PlastoFluidSolidPorousPressureMultiYield(dependent, independent)
ElasticFiber
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Addition of “SiF” capability
♦ Objectives– All development consistent with OpenSees OOP and modular structure
– Enable SiF analysis including fire and heat transfer calculations– Enable SiF analysis on “damaged” model after earthquake analysis
CFD dataLocal / movingZoneParametricStandardFiresFlux orTemp. q(t) q(t) q(z,t) q(x,y,z,t) q(x,y,z,t)
Hea
t Tra
nsfe
r Sla
bB
eam
Col
umn
T(z,t) T(z,t) T(z,t) T(x,y,z,t) T(x,y,z,t)
T(y,z,t)T(x,z,t)
T(y,z,t)T(x,z,t)
T(y,z,t)T(x,z,t) T(x,y,z,t)
T(x,y,z,t)
T(x,y,t) T(x,y,t) T(x,y,z,t) T(x,y,z,t) T(x,y,z,t)
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New thermo-mechanical classes
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New heat transfer classes
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Thermal benchmarks
Phase change benchmark
0.00 0.02 0.04 0.06 0.08 0.100
10
20
30
40
50
60 Analytical Solution 4-noded, dt = 2s 8-noded, dt = 2s
T /
°C
x / m
T = 100 sinπt
40
◦CT = 100 sin
πt
40
◦C
T = 0◦CT = 0
◦C
x = 0.0mx = 0.0m x = 0.1mx = 0.1mx = 0.08mx = 0.08m
(a) geometry and boundary conditions
(b) FE discretised mesh
0 20 40 60 80-30
-20
-10
0
10
20
30
40
Analytical Solution 4-noded, dt =2s 8-noded, dt = 2s
T /
°C
t / s
Transient boundary condition benchmark
600
550
50045
0
400
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
0.1
0.2
0.3
300
400
500
600
Testing local fire
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Thermo-mechanical Benchmark 1
1 2 3
1 2
0T∆ ≠ 0T∆ =
1m 1m
0.1m
0.1m
1 2 3
1 2
0T∆ ≠ 0T∆ =
1m 1m
0.1m
0.1m
2.8e8
σ
ε
E0
Esh
T=400
2.8e8
σ
ε
E0
Esh
T=400
Left half of steel restrained beam subjected to a uniform temperature increment, ∆T = 1000oC
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0 100 200 300 400 500 600 700 800 9000.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
Did
plac
emen
t (m
m)
Temperature (oC)
ABAQUS OpenSees
0 100 200 300 400 500 600 700 800 9000
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
Temperature (oC)
ABAQUS OpenSees
Str
ess
(MP
a)
1 2 3
1 2
0T∆ ≠ 0T∆ =1 2 3
1 2
0T∆ ≠ 0T∆ =
u
Benchmark 1 result
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6m0.1m
0.2mKr Kr
Kt6m
0.1m
0.2mKr Kr
Kt
0 200 400 600 800 10000.0
5.0x104
1.0x105
1.5x105
2.0x105
Mod
ulus
of e
last
icity
(M
Pa)
Temperature (oC)
Ttop=0
Tbot=100oC-1000oC
Single beam subjected to uniformly distributed load and thermal gradient
Height of section
Temperature distribution
UDL=1kN/m
Thermo-mechanical Benchmark 2
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Free end Spring end Pin end
0 200 400 600 800 10000
2
4
6
8
10
12
Hor
izon
tal d
ispl
acem
ent (
mm
)
Temperature at the bottom of the beam (oC)
ABAQUS-Free end ABAQUS-Spring end OpenSees-Free end OpenSees-Spring end
0 200 400 600 800 10000
50
100
150
200
250
300
350
Temperature at the bottom of the beam (oC)
Def
lect
ion
at m
id-s
pan(
mm
)
ABAQUS - free end ABAQUS - Spring end ABAQUS - Pin end OpenSees - free end OpenSees - Spring end OpenSees - Pin end
Benchmark 2 results
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0 200 400 600 800 1000
-1800
-1600
-1400
-1200
-1000
-800
-600
-400
-200
0
ABAQUS - Spring end ABAQUS - Pin end OpenSees - Spring end OpenSees - Pin end
Temperature at the bottom of the beam (oC)
Axi
al fo
rce
(KN
)
0 200 400 600 800 10000
50
100
150
200
250
Temperature at the bottom of the beam (oC)
ABAQUS - free end ABAQUS - Spring end ABAQUS - Pin end OpenSees - free end OpenSees - Spring end OpenSees - Pin end
Mom
ent a
t mid
-spa
n (K
N.m
)
Benchmark 2 results
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0 200 400 600 800 1000 1200
0
50
100
150
200
250
300
Temperature at the bottom of the beam ( oC)
Def
lect
ion
at m
id-s
pan(
mm
)
ABAQUS - Pin end ABAQUS - Spring end ABAQUS - Fix end OpenSees - Pin end OpenSees - Spring end OpenSees - Fix end
0 200 400 600 800 10000
20
40
60
80
100
120
140
160
180
200
Temperature at the bottom of the beam (oC)
Rot
atio
n of
the
end
(10-
3 rad
)
ABAQUS - Pin end ABAQUS - Spring end OpenSees - Pin end OpenSees - Spring end
Pin end Spring end Fix end
Benchmark 2 results
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0 200 400 600 800 1000
-10000
-8000
-6000
-4000
-2000
0
ABAQUS - Pin end ABAQUS - Spring end ABAQUS - Fix end OpenSees - Pin end OpenSees - Spring end OpenSees - Fix end
Temperature at the bottom of the beam (oC)
Axi
al fo
rce
(KN
)
0 200 400 600 800 1000 1200
-300
-200
-100
0
100
200
300
Temperature at the bottom of the beam (oC)
ABAQUS - Pin end
ABAQUS - Spring end
ABAQUS - Fix end
OpenSees - Pin end
OpenSees - Spring end
OpenSees - Fix endM
omen
t at m
id-s
pan
(KN
.m)
Benchmark 2 results
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0 200 400 600 800 1000 1200
-250
-200
-150
-100
-50
0
50
100
150
200
250
300
350
Mom
ent o
f bea
m a
t mid
-spa
n (K
N.m
)
Temperature at the bottom of the beam (oC)
Kr=0 Kr=3e6 Kr=1.5e7 Kr=3e7 Kr=3e8 Kr=3e9 Kr=Infinite
Kr KrKr Kr
Benchmark 2 results
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F1 F2
1240
1170
v4
u2
F1=112kN
F2=28kN
F1 F2
1240
1170
v4
u2
F1=112kN
F2=28kN
0 100 200 300 400 500 600
0
5
10
15
20
25
30
35
40
45
Dis
plac
emen
t (m
m)
Temperature (oC)
EHR Frame u2: Test v4: Test u2: OpenSees v4: OpenSees
0 100 200 300 400 500 600
5
10
15
20
25
30
35
40
45
Temperature (oC)
Dis
plac
emen
t (m
m)
ZSR Frame u1: Test u2: Test u1: OpenSees u2: OpenSees
EHR Frame ZSR Frame
Rubert and Schaumann, Fire Safety Journal, 10, 173-184, 1986
Validation problem 1
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3000
1500
1300
Raft top Raft top
500
Ventilationopening
Fire level/Topof beam
Typical column,300 x 300
Plinth beam,230 x 230
Footing,1100 x 1100 x 500
Bricked box container filledwith sand with fuel tray on top
(level with the top of beam)
Roof slab120 thk
Roof beam230 x 230
Steel framingsystem
Simulated gravityloading of 2nd and 3rdabove floor
Superimposed live loadon floor 1
Extendedcolumn
Reactionwall
4300
5000
Hydraulicjack
Thermocouples at fivedifferent elevation levelsin three plan locations offire compartment
Validation problem 2
Full scale test of damagedRC frame subjected to fireIIT Roorkee, India (UKIERI funding)
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2D frame model & cyclic loading
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Response over 13 cycles
-200 -100 0 100 200
-300
-200
-100
0
100
200
300
Horizontal dsiplacement (mm)
Tot
al R
eact
ion
For
ce (
kN)
node1
1 23
displacement – force curve of control node 1
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-80 -60 -40 -20 0 20 40 60 80-300
-200
-100
0
100
200
300
App
lied
For
ce (
kN)
Horizontal Dsiplacement (mm)
node 1
1 2
3
Comparison with test (5 cycles)
-350
-250
-150
-50
50
150
250
350
-100 -80 -60 -40 -20 0 20 40 60 80 100
Load
(KN
)
Displacement (mm)
Load-Displacement Plot for Roorkee Frame
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Fire loading
0 200 400 600 800 1000
-140
-130
-120
-110
-100
-90
-80
-70
-60
Hor
izon
tal d
ispl
acem
ent (
mm
)
Temperature at the edge of the beam toward fire (C)
node1 node2
1 23
0 200 400 600 800 1000
-30
-25
-20
-15
-10
-5
0
5
Mid
-spa
n de
flect
ion
(mm
)
Temperature at the edge of the beam toward fire (C)
node 3
1 23
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Residual strength testing
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Final remarks
♦ 2D-3D truss and 2D beam-column element completed and tested
♦ New C++ OOP heat transfer code completed and tested
♦ Work progressing on 3D beam-column, shell and 3D heat transfer
♦ Interfacing fire-heat transfer-structural analysis should begin soon
♦ Fully functional capability expected by summer 2012
♦ All code (after exhaustive testing and benchmarking) will be offered to be included in OpenSees official release for free open-source access
♦ OpenSees is becoming a “community code” for the earthquake engineering, it makes sense for it to be adopted by the SiF community as well
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0 200 400 600 800 1000
0
50
100
150
200
250
300
Def
lect
ion
at m
id-s
pan
(mm
)
Temperature at the bottom of beam (oC)
Theory - UDL only OpenSees - UDL only Theory - UDL+T,y OpenSees - UDL+T,y
0 200 400 600 800 1000
0
5
10
15
20
Def
lect
ion
at m
id-s
pan
(mm
)
Temperature at the bottom of beam (oC)
Theory - UDL only OpenSees - UDL only
Benchmark 2 results