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Numerical Modeling of Duplex Stainless
Steel Structures
Priscila das N. Pereira
William M. Pereira
Isabella Pinheiro Gueiros
Luciano Rodrigues Ornelas de Lima
Pedro Colmar Gonçalves da Silva Vellasco
José Guilherme Santos da Silva
Structural Engin. Department - UERJ – Rio de Janeiro, Brasil
August 31 to September 2011
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FCTUC - Portugal
June 22-24. 2008
Chicago. USA
Summary
Introduction
Objectives & Methodology
Design Codes Recommendations
Numerical Model
Parametric Analysis
Results Analysis & Discussion
Concluding Remarks
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June 22-24. 2008
Chicago. USA
Introduction
Stainless steel various types of
constructions high corrosion resistance,
durability, fire resistance, ease of maintenance,
appearance and aesthetics
Cost reduction less need for structure
maintenance & increase in its capacity to
dissipate impact loads stainless steel
structure reliability
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FCTUC - Portugal
June 22-24. 2008
Chicago. USA
Introduction
Arco de Malizia, Italy
Piove di Sacco, Italy
Stainless steel structures examples
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June 22-24. 2008
Chicago. USA
Objectives / Methodology
Development of a numerical model based on FEM
Evaluate LTB Beams Behaviour
RHS Tubular Joint Resistance
imperfection introduction
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FCTUC - Portugal
June 22-24. 2008
Chicago. USA
Design Rules
Duplex Stainless Steel Beams Eurocode 3
Particular case non-symmetrical patterns different
bending moment diagrams
ULS LTB based on Mcr
• kz rotation end conditions
• kw warping end conditions
• zg relation between load application point and shear centre
• zj degree of assymmetry of the cross section
g2
2
g2
Z
2
T
2
z
Z
W
2
W
z
2
z
Z
2
1cr zCzC
IE
IG)Lk(
I
C
k
k
)Lk(
IECM
Geometrical characteristics updated for
Castellar beam properties
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June 22-24. 2008
Chicago. USA
Design Rules
RHS Tubular Joints Eurocode 3, CIDECT & Feng
& Young Formulation
Eurocode 3
CIDECT
Feng & Young
5M
11
2
00yn
Rd,1 /1.4sen
.2
sen.1
t.f.kN
i
2
00y
fu
*
1sen
t.f.Q.QN
1
4
sen.1
.2Q
i
u 1C
f n1Q
1,1.N.N 1Anp1 0
0A
t100
b1
5M
11
2
00yn
1 /1.4sen
.2
sen.1
t.f.kN
ULS
- c
hord
face
failu
re
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June 22-24. 2008
Chicago. USA
Design Rules
Deformation limit proposed by Lu et al. T Joints
Serviceability limit (Ns) Ds = 0.01d0
Ultimate strength (Nu) Du = 0.03d0
If Nu/Ns ≤ 1.5 Nu
If Nu/Ns > 1.5 Ns
P
D 1%d0 3%d0
Ns
Nu
D
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June 22-24. 2008
Chicago. USA
Numerical Models
Beams shell elements SHELL181
beam member plates mid-surfaces
Material multi-linear s x e
Geometrical Non-linearity (Updated Lagrangian) (Identification of yielded points)
imperfection introduction
eigenvalue analysis
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June 22-24. 2008
Chicago. USA
Numerical Models
Imperfection Considerations
Load step 1
Eigenvector for 1st buckling
mode
Application of imperfection
factor based on EC3 limits
Load step 2
Nonlinear analysis
material and geometrical
nonlinearities 0
10
20
30
40
50
60
70
0 5 10 15 20 25
app
lied
be
nd
ing
mo
me
nt
[kN
]
vertical displcament [mm]
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FCTUC - Portugal
June 22-24. 2008
Chicago. USA
Numerical Models
RHS Joints shell elements SHELL281
beam member plates mid-surfaces
Material multi-linear s x e
Geometrical Non-linearity (Updated Lagrangian) (Identification of yielded points)
X
Feng & Young
Experiments
Section (h x b x t) E sp s0.1 sy= s0.2 s0.5 s1.0 su ef (%)
Chord 160x80x3 208000 167 481 536 570 595 766 40 Brace 40x40x2 216000 164 633 707 748 780 827 29
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Chicago. USA
Numerical Model Calibration
Experimental results Feng &Young
0
20
40
60
80
100
120
0 5 10 15 20 25 30 35 40
Load
[kN
]
Displacement [mm]
Numerical
Experimental
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June 22-24. 2008
Chicago. USA
Parametrical Analysis
Duplex stainless steel beams – LTB
W300x150 welded profile → 300mm height,
160mm flange width, 9.5mm flange thickness
&4.7mm web thickness
8 span lengths → from 1 to 8m corresponding →
lLT between 0.57 & 3.15
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June 22-24. 2008
Chicago. USA
Parametrical Analysis
Duplex stainless steel beams – LTB
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
M/Mpl
lLT
Eurocode 3
Numerical - Ansys
Numerical versus Eurocode 3
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June 22-24. 2008
Chicago. USA
Parametrical Analysis
Duplex stainless steel beams – LTB
0
10
20
30
40
50
60
70
0 5 10 15 20 25
app
lied
be
nd
ing
mo
me
nt
[kN
]
vertical displcament [mm]
Ultimate bending moment = 57.64 kN.m
von Mises stress distribution (in MPa) →
observed → plastic bending moment
resistance → not reached in this case,
i.e., 479.61 kN.m
Adopted yield stress for → duplex
stainless steel → 526.68 MPa
7m span
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June 22-24. 2008
Chicago. USA
Parametrical Analysis
RHS duplex stainless steel joints
Model ID
Geometry
Chord Brace β 2
h0 b0 t0 h1 b1 t1
1 160.5 80.6 2.96 40.1 40.3 1.96 0.50 27.23
2 160.5 80.6 3.26 40.1 40.3 1.96 0.50 24.72
3 160.5 100.6 2.96 40.1 40.3 1.96 0.40 33.99
4 160.5 100.6 3.26 40.1 40.3 1.96 0.40 30.86
5 160.5 120.6 2.96 40.1 40.3 1.96 0.33 40.74
6 160.5 120.6 3.26 40.1 40.3 1.96 0.33 36.99
7 160.5 140.6 2.96 40.1 40.3 1.96 0.29 47.50
8 160.5 140.6 3.26 40.1 40.3 1.96 0.29 43.13
9 160.5 150.6 2.96 40.1 40.3 1.96 0.27 50.88
10 160.5 150.6 3.26 40.1 40.3 1.96 0.27 46.20
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Parametrical Analysis
RHS duplex stainless steel joints
Model
ID Nu Ns Nu/Ns Ndef N1,Rd N1
* N1np
1 47.4 32.4 1.5 47.4 35.6 32.3 28.7 0.8 0.7 0.6
2 59.1 41.0 1.4 59.1 43.1 39.2 36.1 0.7 0.7 0.6
3 30.7 18.1 1.7 27.1 30.2 27.5 22.2 1.1 1.0 0.8
4 38.0 22.9 1.7 34.4 36.6 33.3 28.1 1.1 1.0 0.8
5 23.3 12.2 1.9 18.2 27.5 24.9 18.1 1.5 1.4 1.0
6 29.2 15.6 1.9 23.4 33.3 30.3 23.3 1.4 1.3 1.0
7 19.5 8.8 2.2 13.3 25.7 23.4 15.0 1.9 1.8 1.1
8 24.4 11.5 2.1 17.3 31.2 28.4 19.7 1.8 1.6 1.1
9 18.2 7.7 2.3 11.6 25.1 22.8 13.7 2.2 2.0 1.2
10 22.7 10.1 2.2 15.2 30.4 27.7 18.2 2.0 1.8 1.2
def
Rd,1
N
N
def
*
1
N
N
def
np1
N
N
EC3 CIDECT Feng & Young
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June 22-24. 2008
Chicago. USA
Final Remarks
Present paper → evaluation → lateral buckling
capacity of duplex stainless steel beams → &
resistance → tubular T joints between RHS
members → constituted → duplex stainless steel
Results → discussed & compared → stress
distribution, force-displacement curves, etc.
Numerical & analytical curves → LTB beams
analysis → Eurocode 3 equations related → these
ULS for carbon steel beams → can also be used for
duplex stainless steel profiles
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FCTUC - Portugal
June 22-24. 2008
Chicago. USA
Final Remarks
RHS joints, → new CIDECT formulation → better
approximation → numerical results → when
compared with Eurocode 3 results
When these two values → compared with the Feng
and Young values, → concluded → this formulation
presented → better results → when compared →
two first ones.
Acknowledgements: CAPES, CNPq, FAPERJ and
UERJ financial support provided to enable the
development of this work
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June 22-24. 2008
Chicago. USA
Acknowledgements
Thanks for your attention
Contacts: [email protected] and [email protected]