Nonlinear Modeling With OpenSees

 Nonlinear Modeling with OpenSees SE220 Fall 2015 Instructor: Professor il!erto Mos"ueda

#utorial !$ %lire&a Sare!anha '( San )iego Material used for this presentation are mostly from OpenSees website/command manuals and SE201B Lecture Notes by rof! "onte!

OpenSees •

OpenSees is a software fra*ewor+ for !uilding finite ele*ent applications in structural and geotechnical s$ste*s,

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#hese applications run on !oth se"uential- parallel- and distri!uted co*puter s$ste*s,

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% fra*ewor+ IS a set of cooperating software co*ponents for !uilding applications in a specific do*ain,

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#he OpenSees fra*ewor+ is written pri*aril$ in the o!.ect oriented language (// though other languages na*el$ ( and Fortran are also used,

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Eisting Softwares short co*es: •

 E*!edding of co*putational procedures in codes *a+es it difficult to eperi*ent 3integration sche*es- algorith*s- sol4ers and ta+e ad4antage of co*puting technolog$ 3Parallel 6 rid (o*puting

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7(losed8source9wasis the nor*- whereas other fields ha4e adopted 7open8 source9software for co**unitiesof users, (losed source is an i*pedi*ent to new research, No sharing of code- !uilding upon others ideas,

)ownload and Install OpenSees 6 #cl http:opensees,!er+ele$,edu

%fter downloading the #cl#+ eecuta!le $ou will need to run it to install t he );;(annot find tcl?5,dll>- $ou ha4e s+ipped this step and *ust reinstall tcl, Note that $ou wil pro!a!l$ ha4e to uninstall the 4ersion $ou .ust installed first,

#cl

OpenSees Interpreters •

#he OpenSees interpreters are tcl interpreters which ha4e !een etended to include co**ands for finite ele*ent anal$sis: 1, Modeling @create nodes- ele*ents- loads and constraints 2, %nal$sis @specif$ the anal$sis procedure, A, Output specification @specif$ what it is $ou want to *onitor during the anal$sis,

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Being interpreters- this *eans that the files $ou create and su!*it to the OpenSees interpreters are not input files, Cou are creating and su!*itting PDOD%MS,

Main %!stractions in OpenSees Fra*ewor+ 

OpenSees i+i

hat is a )o*ainG

Material

Materials

Steel02 Material 88 iuffrH8Menegotto8Pinto Model with Isotropic Strain ardening

Model co**and

#russ Ea*ple

h$ Nonlinear %nal$sis

#ransfor*ation

Building Model 8 #ransfor*ation

Force Based and )isplace*ent Based

Integration Points

P)elta ra4it$ (olu*n

hat is an %nal$sisG

%nal$sis

%nal$sis •

(onstraint co**and #he (onstraint andler o!.ect deter*ines how the constraint e"uations are enforced in the anal$sis, (onstraint e"uations enforce a specified 4alue for a )OF- or a relationship !etween )OFs,

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 Nu*!erer co**and #he )OFNu*!erer o!.ect deter*ines the *apping !etween e"uation nu*!ers and degrees8of8 freedo* 88 how degrees8of8freedo* are nu*!ered,

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S$ste* co**and #his co**and is used to construct the ;inearSOE and ;inearSol4er o!.ects to store and sol4e the s$ste*  of e"uations in the anal$sis

 8 to specif$ how *atri e"uation J' K D is stored and sol4ed

%nal$sis •

#est co**and (ertain Solution %lgorith* o!.ects re"uire a (on4ergence #est o!.ect to deter*ine if con4ergence has !een achie4ed at the end of an iteration step

%nal$sis •

%lgorith* co**and #his co**and is used to construct a Solution %lgorith* o!.ect- which deter*ines the se"uence of steps ta+en to sol4e the non8linear e"uation

%nal$sis •

Integrator co**and

%nal$sis •

 New*ar+ integrator 

%nal$sis •

 New*ar+ integrator 

%nal$sis 8 Static

%nal$sis 8 #ransient

%nal$&e (o**and

Ea*ple %nal$sis

Ea*ple @ )isplace*ent (ontrol

Ea*ple @ #ransient %nal$sis

Eigen4alue %nal$sis

Output Options

Decorder Options

Etras •

'sing OpenSees in Batch Mode •

(alling OpenSees fro* a *atla! script

L in4o+e Matla! OpenSees opsScript,tcl

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Parallel processing using OpenSeesSp

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Sensiti4it$- Delia!ilit$ and Opti*i&ation %nal$sis http:opensees,!er+ele$,eduwi+iinde,phpSensiti4it$%nal$sis http:opensees,!er+ele$,eduOpenSeeswor+shopsOpenSees)a$s2011B5MS,pdf  http: .aguar,ucsd,eduOpenSees,ht*l

OpenSees Desource •

Message Board http:opensees,!er+ele$,educo**unit$inde,php

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etting Started Manual http:opensees,!er+ele$,eduwi+iinde,phpettingStarted

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(o**and Manual http:opensees,!er+ele$,eduwi+iinde,php(o**andManual

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'ser Ea*ples http:opensees,!er+ele$,eduwi+iinde,phpEa*ples

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OpenSees or+shops)a$s http:opensees,!er+ele$,eduwi+iinde,phpOpenSees)a$s2011

(onclusion •

OpenSees is a powerful tool for perfor*ing FE anal$sis

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It NEE)S contri!utions fro* others to grow

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OpenSees ;IJE %NC si*ulation tool re"uires the user to understand the theor$ and li*itations

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OpenSees 3if features are full$ utili&ed will allow $ou to generate *odels faster and *ore accuratel$ than $ou could with a 'I and will allow $ou to o!tain infor*ation on the 'ncertaint$ using parallel co*puting resources that is the do*inant co*puter architecture a4aila!le toda$,

 Notes •

OpenSees is pri*aril$ a research tool at this ti*e- !ut fairl$ sta!le and is used in professional practice

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%s with an$ nonlinear anal$sis- it re"uires careful consideration of *odel and interpretation of results

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It is under continual de4elop*ent !$ students- facult$ and other researchers

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'ser interface de4elop*ent lags !ehind co*putational technolog$

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It is not !ullet8proof 

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 %n in4est*ent of ti*e and learning is re"uired

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#he OpenSees open-source community  re"uires contri!utions for the co**unit$ to succeed,

%s+ these "uestion fro* $ourself !efore *odeling •

)ata: eo*etr$ and *aterial properties e,g,- set span 100 node 1 span 0

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hat +ind of Material Model are $ou going to use G e,g,- elastic- Steel01- (oncrete01- 

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hat +ind of ele*ents are $ou going to useG e,g,- truss- &ero;ength- dispBea*(olu*n- forceBea*(olu*n -

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hat t$pe of constraintsG e,g,- fi- e"ual)OF- 

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hat +ind of loads or ecitationG e,g,- pattern

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hat +ind of anal$sis are $ou going to perfor*G e,g,- anal$sis Static

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hat +ind of response do $ou want to *onitorrecordG e,g,- recorder- 

Building Model 8 eo*etr$

OpenSees doesn’t have a built-in units! Use consistent units!

Building Model

1 1(

node $nodeTag (ndm $coords) node $nodeTag $xcor $ycor 

2

&

'

( 1)

Building Model 8 (onstraints S (single point constraint)

 (multiple points constraint)

" #inge connection (beteen truss elements and gravity column nodes)

Building Model 8 Materials

Building Model 8 sections   

" section properties (%&S' manual)

Building Model 8 #ransfor*ation " eometric *onlinearity

Building Model 8 Ele*ents

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 !ea*ithinges ele*ent o!.ect is !ased on the non8iterati4e 3or iterati4e flei!ilit$ for*ulation- and considers plasticit$ to !e concentrated o4er specified hinge lengths at the ele*ent ends,

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 Note- the !ea*ithinges ele*ent locali&e plastic hinging at the ele*ent ends onl$,

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#his t$pe of ele*ent di4ides the ele*ent in three parts: •

two hinges at the ends-

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and a linear8elastic region in the *iddle,

#he hinges are defined !$ assigning to each a pre4iousl$8defined section, #he length of the each hinge is also specified !$ the user:

Building Model @ Bea*ithinges Ele*ent &ntegration points

#he !ea*ithinges ele*ent used here has four elastic sections and two fi!er section at the end, #herefore for output in specif$ing secNu*: secNu*K1: hinge at node i secNu*K: hinge at node .

Building Model 8 Ele*ents

Building Model @ Mass and ra4it$ ;oads

Building Model @ ra4it$ %nal$sis

Building Model @ Eigen4alue anal$sis

Building Model @ )a*ping

Building Model @ EQ ecitation

Building Model @ #ransient %nal$sis

Building Model @ Decorders 3outputs

Decorders •

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 Nodes:

Ele*ents:

'se: 'se eit to finish and wipe !efore running the net one,

Pusho4er %nal$sis •

Pattern

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)isplace*ent (ontrolIntergrator 

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;oad (ontrolIntergrator 

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%dapti4e Pusho4erG •

De"uires 7eigen anal$sis9 during pusho4er anal$sis

Duau*o+o Ele*ents

Duau*o+o Ele*ents

Duau*o+o Ele*ents

Duau*o+o Ele*ents

Duau*o+o Ele*ents

Duau*o+o Ele*ents

Plastic hinge &one and rotation capacities