Fall 2002 Ben Schafer thin-walled structures research group.
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Transcript of Fall 2002 Ben Schafer thin-walled structures research group.
Fall 2002Ben Schafer
thin-walled structures research group
Testing of cold-formed steel beams
• Jack Spangler• Jim Kelly• Cheng Yu• …most of the CE Grads• Sam Phillips• Liakos Ariston• Tim Ruth• Andrew Myers• …other CE undergrads• Michael Manness, Jr.
Cold-formed steel beamscheng yu
• Testing– first tests with definitive
separation of modes– upper and lower bound
flexural capacities– experimental evidence for
new design methods• FE Modeling
– parametric studies– moment gradient effect– influence of restraint
• Significant design impact
Distortional
Local
EA/GA and member optimizationsam phillips
Special: 2 hour “Short Course”Thursday September 26, 2002
1:00pm to 3:00pmShaffer Hall Room 101
Evolutionary Computation and Civil/Structural Engineering:A Look Back and a Look Forward
Assoc. Prof. Chris Foley Marquette University
collapse of thin-walled membersbadri hiriyur
Pxm
Px
Pcrx
o
xP̂
P
Pm
PPcr
o
P̂
P
Pm
PPcr
o
P̂
P
Pcrx
Pcr
P
Pxm
P m
(d) example full model response
(b) unstable sway mode
P
k
kx
kx
F
x
Fy
k
M
y
L/2
L/2
P
k
kx
kx
F
x
Fy
k
M
y
L/2
L/2
(a)bar-spring model (c) stable local mode
collapse of corrugated plastic pipe
X
Y
Z
V1L21C10
s y m m e t r y a lo n g e d g e s e n f o r c e d
s y m m e t r y e n f o r c e da t s p r in g l in e
s y m m e t r y e n f o r c e da t c r o w n
c r o s s - s e c t io n
l in e r
c r e s t
v a l le y
X
Y Z
V1G4
Output Set: Step 1, Inc 19Deformed(1.354): Total Translation
generalized beam theorypuneet bajpai
Unifies the conventional theories
Better understanding of structural principles
Economical method of analysis
Capability to consider individual buckling modes and select combinations of them
Applicable to linear analysis (First-order GBT), linear stability analysis (General second-order GBT), or bifurcation problems
q VWVB VD GVCE kjiijk
ji
kkkkkk '''''''' )(
Basic equation of second-order theory :
where, E = Young’s modulus, G = shear modulus,
BDC kkk ,, = section properties applicable to mode k,
Vk = generalized deformation in mode k
qk
= distributed load applicable to mode k,
= three dimensional array of second-order terms, which includes coupling terms ijk
Stochastic post-bucklingjie li, prof. lori graham
/c = 1 + a + b2 + …,
V = cV0 + (acV0 + V1) + (bcV0 + V2)2 + …
covered wooden bridgesdylan lamar (u of ark), erika stoddard, steve buonopane
Pine Grove Bridge - Lancaster Co., PA
Brown Bridge - Rutland Co., VT
Reliability and advanced analysissteve buonopane, prof. tak igusa
Ziemian frame testbed problem Strength at first plastic hinge
no correlationto ult. strength
Ultimate Strength (via Adv. Anal.) Failure probability estimation
Solver efficiency for reliability and optimizationzailong wan, prof. dan naiman, prof. tak igusa
{F}=[Kt]{d}
[Kt]=
buildingbasic geom.basic loads
perf. criteria
building realization(s)input
MASTANinterface
deterministic response study seek efficiency through
topology
•symm.•pos-def.•sparse•topology unchanging
wind on low-rise buildingsprof. nick jones
Hurricane Loss ReductionWind and Structural Engineering Initiative
through National Institute of Standards and Technology
Building and Fire Research LaboratoryGaithersburg, Maryland