Influence of Material Strength on Ultimate Strength of ...
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Influence of Variation in Material Strength on Ultimate
Strength of
Stainless Steel Plates
under In-Plane Bending and Compression
Satoshi NARA
Osaka University
Yasuhiro MIYAZAKI Nagaoka National College of Technology
4th Internatonal Experts Seminar
6-7 December 2012, Ascot, UK
I saw Brocken spectre (Brocken bow) on the River Thames
just before landing to Heathrow.
Brocken spectre (Brocken bow)
at the top of a mountain
in an airplane
Japanese believes it is a sign of happiness. In fact, I met
Prof. Camotim, Prof. Rasmussen, Dr.Jandera supervised by
Prof. Machacek, and Dr.Rossi from University of Liege
where I had stayed and been hosted by Prof. Maquoi for
one year.
Outline of presentation
1 Background of the research
2 Material properties
3 Numerical analysis
4 Results and discussion
5 Conclusion
1.Background of the research
Stonecutters Bridge wikipedia: http://en.wikipedia.org/wiki/Stonecutters_Bridge
•Stainless steel has high
corrosion resistance
•Stainless steel bridge saves
costs and labor for
maintenance and
management
Design standards for steel and composite structures, in
which stainless steel is defined as a kind of structural steel,
has published by JSCE(Japan Society of Civil Engineers).
Two design standards has already specified by JSSC
(Japan Society of Steel Construction),
- for general building structures(1995),
- for light-weight stainless steel structures(2005).
The third design draft for civil structures is now in
preparation, and will be introduced in the JSCE design
standards.
However, 1) Expensive costs
Government pays construction costs of civil structures,
There are few who believe in low Life Cycle Costs(LCC). 2) No design standards for civil structures except for special ones
No alternatives to select stainless steel,
Small market still continues.
Moreover, 3) Circumstances of design codes
0.1% proof stress?
which is regulated by design standards for building structures,
0.2% proof stress?
which is specified by the Japan Industry Standards(JIS).
stainless steel design
method
•initial imperfection
•material properties unadapted
Simply supported stainless steel plate
ultimate strength
•uniaxial compression
•in-plane bending
Influence of variation in material
strength on ultimate strength
2.Material properties Type of stainless steel
Austenitic stainless steel
• SUS304
• SUS316
• SUS304N2
Ferritic stainless steel
• SUS410L
Duplex stainless steel
• SUS329J3L
Table 1 Statistical data of austenitic stainless steels
Table 2 5% and 95% fractile based on statistical data
Stress-strain model
Ramberg-Osgood curve
Where, ε and σ are strain and stress, respectively.
Fig.1 Stress-strain curves
Stre
ss
σ
(MP
a)
Strain ε
SUS329J3L_max
SUS329J3L_min
SUS329J3L_exp
SUS410L_max
SUS410L_min
SUS410L_expStr
ess
σ(M
Pa)
Fig.2 Stress-strain curves
3.Numerical analysis
Analytical plate models
Initial deflection
W0max : maximum value of initial deflection(=b/250)
a , b: unloading and loading length
Plate slenderness
k: buckling coefficient 4.0 for under uniaxial
compression, 23.9 for under in-plane bending
Uniaxial compression 4.Results and discussion
Fig.5 Comparison of ultimate compressive strength normarized
by the minimum proof stress
or
SUS410L_mat
SUS329J3L_mat
SUS410L_max
SUS329J3L_max
σ0.2
σ0.2_min
Fig.6 Comparison of ultimate compressive strength normarized
by the minimum proof stress
In-plane bending
Fig.8 Comparison of ultimate in-plane bending strength normarized
by the minimum proof stress
σ0.2
σ0.2_min
or
SUS410L_mat
SUS329J3L_mat
SUS410L_max
SUS329J3L_max
or
σ0.2
σ0.2_min
Mu
M0.2_min
Fig.9 Comparison of ultimate in-plane bending strength normarized
by the minimum proof stress
5. Conclusion (1) 95%
fractile of material strengths of
(1) SUS304, SUS316 and SUS304N2 based on
(2) statistical data is more than 97% of proof stress
0.2% specified by JIS.
(3) The maximum 0.2% proof stress is from 1.49 to
1.70 times higher than the minimum one, however,
the ultimate compressive and in-plane bending
strength of the plates with the maximum 0.2% proof
stress are 12% and 15% higher than those with the
minimum one, respectively.
Thank you for your kind attention!
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