141
The Open-Source Approach for Computational Modeling and Simulation
for Earthquake Engineering: History, Accomplishments, and Future Needs
.4
Gregory L. Fenves ¿
Cockrell School of Engineering The University of Texas at Austin
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National Autonomous University of Mexico
Mexíco City, Feb. 5, 2015 c
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Fundamentals Are Timeless 38
C. FLIOaBILIrÍ OF A i-p I'1BBa
Considering the slice as the basic elenent of the 1-O camber,
the sarne 000rdinate transformation procese discussed aboye can be
used te c1cu1tta the flexibjljty of any arbitrary 1-D member.
To demonetrate the procedure, the flexjbjljty of a straight, Uaiforni
bar will be evaluated.
1. Unifona Bar y
-
ELAflC PRCPTI.Ç
A-nAI P(cg
- L -------__
(L\ OL
Kc 4 flne first step ja any flexibility cnolysjs is the seleetion of
the forne systen for whjch the fiexlbility is desired. Ifthebarjs
te be used ja structure lying and loaded in one plane, the three forces
ahovn ja the sketch wouJ.d be saltable.
The flexibillty of the bar may now be cbtaned by su=ing up
the internet york ja all Slices of length dx caused by unit values
of these external jorcas, thus F = . 1 (bi)Tf1b 1 JL(bs)Tfsbsdx The
alice flexibiljty f 5 is given in Eq. 13. The jorge tran5formatjoa matrix b5 represente the fornes ja the arbitrary slice at position
"x" causeci by unit values of the externel meniber fornes, thus
P 1 0 0
mz O1- p
M o o o (15)
y MI y L L -JBar y
T o o Oj
nr alice
S 5 = b5R (15a)
Noy ja Calcndatisg the Internet work of t:e &ljce at position "X"
Ray Clough, UC Berkeley, 1960s
PLEKURAL
/ ELt)flt.
But Software Evolves Slow1y
1 Category 1 Command
Basic k
Gcometry
larc
circic
1 spline
lcurv,2, 1, 2,3, 0. 0000 4 04084 0.00000000000 0000e+0 1. 000000000000000e+O 1. 000000000000000e+O 1. 000000000000000e+Ü 1. 000000000000000e+ioü 1.0000000 00000000e+000
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Simulation State-of-the-Art
0 "The Good" - Linear structural analysis routine - Good commercial software widely
used and ¡ntegrated with BlM - Nonlinear static analysis becoming important - Performance methods becoming more widely
used, e.g. ATC 58
9 "The Bad" - Linear analysís with equivalent latera 1 loads is not simulation - Nonlinear static analysis uses very simplified models;
it is not simulation - "Performance criteria" not thoroughly investigated, e.g.
FEMA 356, nor modeis adequately developed - Long way to go in including uncertainty quantification
rs ro
and the Ug1y
• Many non linear analysis methods based on concepts from 1980s at often software architecture from 1970-1980s
• Underinvestment in research in simulation, and what ¡s done is not well organized Poor Iinkages between fundamental experimental studies and modeling; ¡nsufficient validation and verification of models
• Simulation modeis, methods, and computational procedures in earthquake engineering have not kept up with rapid advances in computing hardware, software engineering, databases, network communicatíons - Limited interaction with computer science - Inadequate education of students in computing
Observations on Historical Situation
with Simulation Software
• Tight binding of modeis in research and commercial codes is an impediment to new research and implementation of modeis for professional practice.
• Embedding of computational procedures in codes makes it difficult to experiment and take advantage of computing technology:
- Parallel and distributed computers
- Computational grids
- Now, cloud computing
• "Closed-source" ¡s the norm, whereas other fields have adopted "open-source" software for communities users.
Simulation Needs in Earthquake Engineering
• Performance-based engineering depends on evaluation of damage and estimate of consequences
• Rational, validated modeis of behavior of structural and geotechnical materlais, components and systems are needed for simulating performance
• Simulation applications: - Assessment of performance - Design using parameterized modeis, including
optimization with performance constraints - Reliability-based desígn - Regional loss estimation and disaster planning
• Additional applications include structural and system health monitoring for control and operations
Simulation Has Transformed
Other Engineering and Science Fie1ds £ • Computational chemisiry,
Simulation- Based computational bioiogy Englneering Science
• F\/1 a te r ¡ a 1 s ci e 11 ce, p a rt ¡ c u 1 a rl y a t Sinn,lo,io,, nano-scale
• Computational fluid dynamics S.dE,g,ong
- Aerodynamics - Building interior environment - Virtual wind tunnels
• Aircraftdesign • Automotive design • U.S. nuclear weapons stewardship
(ASCI, PSAAP)
fN
Vision for Earthquake Engineering Simulation (2007)
NEES
Computational modeling and simulation is central to the vision of NEES to transform the development of new earthquake engineering solutions from being primarily based on experiments to a balanced use of simulation and experimentation using computational modeis validated by experimental data.
A close integration of modern computational modeis and simulation software with other NEES applications and services will provide the earthquake engineering community, and broad engineering users, new capabilities for developing innovative and cost-effective solutions.
NEES George E. Brown. Jr
Network for Earthquake Engineerrng Simuiation
a -1: (op n riu Te±icic.rv V:ir cf tIe 3.rdfDtec:'r; c'EE". la:.
Information Technology within the George E. Brown, Jr. Network for Earthquake Engineering Simulation:
A Vision for an Integrated Community
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09
Software Frarnework
• A framework is a set of cooperating software components for buiiding appIications in a specific domain
• Aframework dictates the architecture of the appiication - it represents the design decisions common to the appiication domain
• A frameworks is based on the assumption that an architecture wili work for most appiications within the domain
• Loose-coupiing of components within the framework is essentiai for extensibiiity and re-usability for appiications
• Exam pies: Visualization (GLUT), Hadoop, Googie Apps, • A framework ¡s not a "code"
o
.
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Open System for Earthquake Engineering Simulation P.tcific 1trtIlthIht Iiigincenng Res..trc h Cc fltcr
• OpenSees has been under development by PEER since 1998. NEES supported 2005-2014. PEER since then.
• Windows application downloaded over 10,000 times a year.
• Parallel Applications utilize over 1,000,000 CPU hours on NSF XSEDE compute resources yearly.
• Open-source and royalty free license for non-commercial use and and interna 1 commercial use.
• License must be obtained for software developers including OpenSees code in their applications.
o Written in C++, C and Fortran
(C++ being the main language)
http://opensees.berkeley.edu
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HOME
OpenSees 2.45 Released OPENSEESWIXI
HSAGE BoRD \'ersion 2.4.5 of tieOe,Sees binarv ¡s now avatiable for Jownioad. Fere is the chanqe loo
OpenSees Days Iy June 19-1 211, 215
)OWN LOAD An Opensees Days workshop will be heid at the Ce -npus of the Ulihersity of Sa eno in Fiscioro, to
SOLRCE CODE corsttu:e a meeting point 'or researzhers and practitioners Qn topics elev a nt tD rnodding, aralvsis and
clesign in the ficicis of structural and earthquake engineeriig. Deadi nes to relnemDer: BUG REPORT
• 31 Deceínter 2014 - Aostract submissicn
• 1 March 2015 . Papar submision
• 15 Ma-ch 2015 Early bird egis:ration
For rrore inforna:icxi, please coosult the arochure.
Search Survey — OpenSees rvIissing Pieces Ir cuSIornzethe
tO 5_C We are conducting a sJrvey to tdenty prabems ans shortcominc associated with OpenSees. 'lease help
by lIIinç c*Jt the sicoy.
OpenSces Days 2011
NEES ard PEER hs:ed this years :wo dab evelt 00 Sep:ernber 2526 at the Richmoid fleld Stat on, liC
Berkeley. The prsetatiDns are now avai ¿tble onhine and can te 'ound .her3
'I .' ' pP .enSces in the CIouds!
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United States 264,504 ..
a China 138,279 r%)
= Irar 80,406
11 Italy 61,838
S. 1'1 Canada 52,019 •3J%)
India 39,757 34%)
• Japan 31,569 21%)
United Kinpdom 30,081 6%)
íE Greece 28,644 i%)
;. South Korea 23,567 3%)
0 Turkey 17,957
Germany 12,957 2%)
0 Taiwan 12,380 6%)
14, a New Zealard 10,691
L. Cnie 10,507 Í%)
Portuga 10,297 3%)
Australa 8,865 .3%)
El Hong Kong 7,948 1%)
(not set) 7,939 1%)
.. France 7,098 2%)
El Mexico 6,272 vv)
= Spain 6,216
Pageviews
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Visits
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OpenSees Woridwilde Usage (2014)
1
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OpenSees Approach to Simulation
c Basic approach: - Modular software design for
implementing and integrating modeling, numerical methods, and IT for scalable, robust simulation
- Focus on capabilities needed for performance-based engineering
- Programmab!e interfaces 11 Most users: a "code" for nonlinear
analysis. Fully scriptab!e. • Generaily: a software framework for
developing simulation applications.
Structural Modeling and Simulation
Non-ductile RC frames and calíbration of
buliding code provisions
C. Haselton, G. Delerlein, Stanford -
Joints with both bond-slip springs and shear springs
fl..
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1 Column base ond-sIip springs
Corotational geometric
transformations
- 11 JU 11 1
UC San Diego, 2008
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Examples of OpenSees Applications
• Parametric studies to examine relationship between intensity and damage for PBEE and design procedures
• Computational reliability for PBEE
• Soil-structure-foundation interaction
• Spatial distribution of damage
• Simulation of bridge performance
Conceptual Approach for Simulation
Algorit 1
Solvers nework, ParaIIe sualization, compu com putation
nent, system
1
Simulation Software Architecture
Traditional Code Fra mework of Components
User Interface
Input Language
Base Code
Compute Technology
Applícation Program Interface (API)
Software Depends on Expressiveness
of Language and Power of Processor(s)
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What is Object-Oriented
SM411I4LK-80
Programming?
• Object-oriented programs are composed of objects that bind data and operators on data
• Objects are operated upon by sending messages to it. The public ¡nterface defines the operations on an object
• Object's internal state is encapsulated ¡n the object. The implementation is private
• Classes define the software behavior of objects. • Classes and their objects are designed to represent
key abstractions • A programmer should be able to use a class through
the interface independently of the implementation
Object-Oriented Finite Element
Frametwork r14'Iltvcl I' nil 4 E 1v In4IIt P rogralnllki ng:
Fra IIk4'\<)rk-i for i IIi Iv-i-. A l!.!pri 1 IIH4 a 11(1 Pa ial tul
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Structural Modeis as Aggregation Pattern
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Analysis Class for Simulation
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Example of Analysis Class
El ernent
u p
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p = af q
715 Linear
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q2 ,t
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q=j aTscix q2,t
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e=av
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v1 q
Basic System
e lJ s S ection
Force
s=bq
y =fbbTedx
L e = ase s =fA'
Material
o = G(E )
No assumptions are made on section or material behavior; each level
in the hierarchy can be defined independently of other leveis
Form Follows Mechanics
acrdA
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Types of Behavior
Ip
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Vu = 125 kips
= 70 kips
V1 =4Bkips
1 2 3 4 5 6 Lateral Dispacernent (iri)
[n(er - 1asticity
• Ductile and brittle modes represented
• Soution method converges rapidly even with strong softening
160
140
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OpenSees Parallel Processing - NP3 NP4 ~ NP5 ~ NP7
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° 30,237 nodes • 1,140/280 linear/nonlinear BC elements * 81 linear shell elements • 23,556 solid brick elements • 1,806 zero-length elements
Click en a directory to enter that directory. Click en a file te display ita revision history and te çjet a chance te display diffs between revisions,
Current directory: [local] / OpenSees / SRC
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converenceTesti/
D coordTransformation/
O damaae/
O deta base,!
docZ o
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O handIr
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OpenSees as Open -Source Software
Open Source ls...
• Roadmap
• Architecture
• Program Interfaces (APFs)
• Code repository
— Checkout/in
— Branch/merge
— Versioning
• Release engineering
• Testing
• Validation & Verification
# set sorne variables
set gMotion el centro 2 D Steel Moment Frame set scale 1.
set roofWeight [expr 80*120.*72./l000.]; #kips;
set floorWeight [expr 95*120 . *71/1000 . 1; set nurnFrameResisting 2.0; #load resisting frames
set percentLoadFrame [expr 15 .1120 .] set dampRatio 0.03
set model 1 ROOF
set mode2 3
set Fy 60. 6
set E 30000. 5 set b 0.03
4
#setuprnylists 3
set floorOffsets {216. 150. 150. 150. 150. 150
set colOffsets {288. 288. 288.}; #inches 2
set colSizes {W30X173 W30X173 W27X11
Load: 95psftypical, roof8Opsf E=29 9 000 9 Fy=50.0, b =0.003 3% Rayleigh Damping lst and 3rd Modes
(1k) (1íi) W24 x 76
(1;),
6h Siory J W24 x 76
W27 x 94
1 W27x94 24 fi -
W30_x_99
n. 2nd Story
W30 x 99
setcoitxizes 1vvI4ÁI9 VV1'4AJi VV14Á1 ' ' •' - '' '' \'_•'
set bearnSizes {W30X99 W30X99 W27X94 W2/X94 W24X/b W24X/bÍ;
# build and run the model using standard template file source SteelMomentFrame2d_UniformExcitation.tcl
5ft
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Concrete Building Study 113 records, 4 intensities 3 hour a record, 1356 hours or 565 days.
Ran on 452 processors Qn XSEDE in Iess than 5 hours.
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set pid [getPIDJ set np [getNP] set count O; source parameters.tcl source ReadSMDFieNewFormaticI: foreach GMf Ile $...de (
foreach Factcrl248 $iFactorl248
if ([expr $count % $np] == $ph) {
set inFile $G.Md...nS.GMf'ie.AT2 set outFile $GM.d.ir/.$. .M.flç.g3; ReadSMDFileNewFormat Sin File $outFile dt nDts;
wipe sou rce GravityAn alysisS cripttc
loacCons: .::me 0.0; wipeAnalys is
source EQRecorder,tcl source EQAnaIyssScript.tcl
if($oko{ us "Process S.id $GMfiIe x $Factorl 248 FINSHED OK modelTime [getTirnejj'
} else Duts Process $GMfile x $Factorl248 FINSHED FAIL modeTíme [getTirne] desredTime S.a.xA..aJysi
}
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jprf Prof Xin-Zheng Lu
Tsinghua University
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How Does OpenSees Compare With Commercial Software?
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so 60
40
Shanghai Tower u
H632m, 124 stories u 53,006 nodes
u 88,089 elements
u 48,774 fiber beam elements u
39,315 multi-layer shell elements
u Memory used: 8.9GB
Similar Resul t -(Results
PGA 4O0g1
100
so
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with commercial applications the same íff model and analysis are the same)
Lessons and Observations
• Many see the benefits of exchanging research and ideas through software
• Success depends on ability of developers to understand abstractions in the software design
• "Not invented here" is sometimes an issue
• Computing education and experience of civil engineers makes the learning curve look steep
• Many users just want the code and are not interested in open-source
• Documentation is never good enough
• Long-term support of an organization is necessary
• Innovation is possible, but it takes long-term commitment
.
Using the Internet for Simulation (2001)
MOdl Bu\d
L Materiais lements
Other
o Solution Procedures
N.J
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Solvers (1)
> Compute Technology
Internet
API's Data bases
Schematic of Simulation in the Future (2002)
aci . modeis org
modelBuiiders cern
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buildingcode. org oomputatiori. com
usgs . gov
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Cloud Computing
Servers Virtua' Desktop Software Platform
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Cloud as Deployed Services
Sofare as a Service
(1) 4)
Platform as a Service
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Infrastructure as a Service
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Deployment modeis
Key Question for the Future
• How will nonlinear simulation modeis based on fundamentais be developed for use in performance-based design?
• How will validation, verification, and uncertainty quantification (VVUQ) be incorporated in earthquake engineering simulation?
• How will the earthquake engineering industry use
transformational cloud-based services?
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