Abaqus Example

(1)

FINITE ELEMENT ANALYSIS IN

**Siddhartha Ghosh* and**

* Assistant Professor, ** Research Scholar (PhD Student )

Department of Civil Engineering

Indian Institute of Technology, Bombay

ELEMENT ANALYSIS IN ABAQUS

Siddhartha Ghosh* and Swapnil B. Kharmale**

* Assistant Professor, ** Research Scholar (PhD Student )

Department of Civil Engineering

Indian Institute of Technology, Bombay

(2)

ABAQUS : General

ABAQUS is a

highly sophisticated

, general

designed primarily to model the behavior

externally applied loading.

Salient features of ABAQUS

Capabilities for both

static and dynamic

The ability to

account all types of nonlinearities

and geometric non-linearity

A

very extensive element library

, including

beam elements, shell and plate elements

A sophisticated capability to

model contact

Capabilities

to model a number of

vibrations, coupled fluid/structure interactions,

and so on.

(From:www.abaqus.comand and www.engin.brown.edu/courses/en

ABAQUS : General

general purpose finite element program,

behavior of solids and structures under

dynamic problems

nonlinearities

viz.

material non-linearity

including a full set of continuum elements,

elements

contact between solids

of phenomena of interest

, including

interactions, acoustics, buckling problems,

(3)

ABAQUS : General

The ABAQUS suite consists of three core products:

• ABAQUS/Standard,

For traditional implicit finite element

thermal, all powered with the widest range

options

• ABAQUS/Explicit

For transient dynamics and quasi-static

appropriate in many applications such

manufacturing processes.

and

• ABAQUS/CAE

(

C

omplete

A

baqus

E

nvironment)

It provides a complete modelling and visualization

analysis products. It has direct access

and visualization

ABAQUS : General

The ABAQUS suite consists of three core products:

analyses such as static, dynamics,

range of contact and nonlinear material

static analyses using an explicit approach

such as drop test, crushing and many

nvironment)

visualization environment for ABAQUS

access to CAD models, advanced meshing

(4)

ABAQUS : General

Here we focus on ABAQUS/Standard

Command Line

Solver Structure

ABAQUS STANDARD

Now we will model and analysis a single story

ABAQUS/CAE

(Note that it could be possible to create the

discussed later)

ABAQUS : General

ABAQUS CAE

Solver Structure

ABAQUS STANDARD

story Steel Plate Shear Wall (SPSW1) through

(5)

ABAQUS/CAE Layout

Title bar

Context bar

Tool bar

You can start ABAQUS CAE from the START

abaqus cae in a Command window. Following figure

Message area Canvas & Drawing area Toolbox Area

ABAQUS/CAE Layout

Menu bar Tool bar

START menu or with a command line by typing

figure shows how an ABAQUS/CAE looks

View port

Message area

(6)

ABAQUS CAE modules

I)PREPROCESSING

• Part

–

Create individual parts

• Property

–

Create and assign material properties

• Assembly

–

Create and place all parts instances

• Step

–

Define all analysis steps and the results you want

• Interaction

–

Define any contact information

• Interaction

–

Define any contact information

• Load

-

Define and place all loads and boundary conditions

• Mesh

–

Define your nodes and elements

II)ANALYSIS

• Job

–

Submit your job for analysis

III)POSTPROCESSING

• Visualization

-

View your results

ABAQUS CAE modules

Create and assign material properties

Create and place all parts instances

Define all analysis steps and the results you want

Define any contact information

Define and place all loads and boundary conditions

Define your nodes and elements

(7)

3-Dimensional FEM Problem

(Pushover Analysis of SPSW)

T

o start learning ABAQUS CAE

single story Steel Plate Shear

includes geometric nonlinearity

during fabrication). The specimen

load (Non-linear static pushover analysis)

Problem Statement

To find the ultimate load carrying

story steel plate shear wall (SPSW

analysis.

Dimensional FEM Problem

(Pushover Analysis of SPSW)

we will work through modelling a

Wall (SPSW1) specimen which

(initial out-of-plane deformations

is subjected to monotonic lateral

analysis)

carrying capacity (Lateral load) of single

(SPSW1) by non-linear static push over

(8)

Details of SPSW

Details of SPSW1

(9)

(10)

Selection of Element for Modelling SPSW

Infill Panel

Element

Boundary Element

By using

Selection of Element for Modelling SPSW1

By using 3-Dimensional Shell

(11)

PART MODULE

− Create a new part as Infill_Panel

3-D planar

Type : Deformable Basic feature: shell

Approximate size: 6x6

(Note :- ABAQUS follows consistent unit so be specific to keep same unit. Here we kept SI units i.e. m for length N for force etc)

(12)

Part:-

Infill_Panel

The following picture shows how a Part

Infill_Panel

(13)

− Create another new part as Boundary_Element

3-D planar

Type : Deformable Basic feature: wire Approximate size: 6 x6

(14)

Infill_Panel

and Boundary_Element

ABAQUS/CAE

Boundary_Element

Parts in

ABAQUS/CAE

(15)

We will add the material Steel and give it values

Stress = 2.0E+08N/m2_{,Plastic strain=0} _{(Note that} steel)

We will create section called Shellsection

Shell/Homogenous and assign a thickness of 0.0025

Assign material to this section

Property Module

values E= 2.0E+11N/m2 _{Poisson's ratio ν= 0.3, Yield} that elastically-perfectly plastic relationship is used for Shellsection and give it category of Shell ,Continuous

0025m with thickness integration point 5

(16)

Also create section called Boundarysection_col

Boundarysection_bea and give it category of Beam

Create profile namely Columns and Beams

shaped cross section

Assign same material to this section also

Property Module (Continued)

I-Section profile for Columns

I-Section profile for Beams

Boundarysection_col and

Beam

using

I-Section profile for Beams

(17)

Assign Shellsection to part named Infill_Panel

Assign Boundarysection_col and Boundarysection_bea

to part named Bounary_Element

Property Module (Continued)

Assembly Module

Now we will create two independent instances using

parts

Infill_Panel

and

Boundary_Element

Its easy to mesh the assembly as a whole using

independent instances

Infill_Panel

Boundarysection_bea with Columns and Beams profile

Property Module (Continued)

Assembly Module

Now we will create two independent instances using

Boundary_Element

(18)

Step Module

By default there is a

Initial Step

in Abaqus (i.e.

Boundary Conditions

We will add a step after system made initial step

The procedure type is

General

and type is

nonlinearity is on to account for large deformations

Keep the Output Request as preselected (By Default)

Step Module

. System made step) which is used to define the

called

Transverse load

is

Static

. The

nlgeom=Yes

means geometric

deformations

(19)

Step Module (Continued)

After step called

Transverse Load

create a next

The procedure type is

General

and type is

geometric nonlineaarity is on to account for large

Step Module (Continued)

next analysis step

Lateral Load

is

Static Riks

. Again

nlgeom=Yes

means

large deformations

(20)

Interaction Module

In this module we will define the contact between two independent part namely

and

Boundary_Element

Create surface

Infill_Panel_Master

in part

Infill_Panel

Interaction Module

In this module we will define the contact between two independent part namely

Infill_Panel

(21)

Similarly create surface

Boundary_Element_Slave

Once these surfaces are created we can provide contact between them through

Interaction module

Selection of Master surface

Boundary_Element_Slave

in part

Boundary_Element

Once these surfaces are created we can provide contact between them through

(22)

Selection of Slave surface

(23)

Interaction between two parts namely

(24)

Creating Boundary Conditions in Initial Step

Create boundary conditions in Initial step (System made step)

There are two type of Boundary conditions for this problem namely

Bottom extreme nodes are fixed (U1=U2=U3

Edges are restrained in z-direction (U3=0)

Creating Boundary Conditions in Initial Step

Create boundary conditions in Initial step (System made step)

There are two type of Boundary conditions for this problem namely

3=UR1=UR2=UR3=0)

(25)

(26)

Edges are restrained in z

(27)

Mesh Module

Now we will mesh the assembly

Before that we will assign the shell element to

Infill_Panel

Also assign the beam element to

Boundary_Element

Mesh Module

Infill_Panel

part. The shell element is

S4R

(28)

(29)

(30)

Mesh Module (Continued)

After assigning proper element to each of part next

Here we are using mesh of 20x20 for Infill_Panel

element into 20 parts. So for whole assembly

mesh

Mesh Module (Continued)

next step is

seeding.

Infill_Panel part and we will discritize each boundary

(31)

Meshing of whole Assembly of SPSW

Meshing of whole Assembly of SPSW1

(32)

Load Module

STEP:- Transverse Load

:- Apply a concentrated load (named as

node in negative z-direction (i.e. Along 3-axis)

Load Module

(33)

Load Module (Continue)

STEP:- Lateral Load

:- Apply a concentrated load (named as

TOPNODES

in positive x-direction (i.e. Along 1-axis).

Remember here we kept the displacement contro

as load control during initial part of analysis

Load Module (Continue)

Apply a concentrated load (named as

CFORCE-2

)of

1000N

at the

axis).

(34)

Job Module

We will create a job called

SPSW1

Once this has been created just submit the job.

The analysis should only take a couple of minutes.

Job Module

Once this has been created just submit the job.

(35)

Here you have an option to

select

analysis

viz

Full

analysis

or

Explicit analysis

or

Restart

Submitting job after elapsed

time

(36)

Visualization Module (Post processing)

−

Once your analysis is complete we want to

−

First we will see the

deformed shape

(

Remember this step is created to have initial out deformed shape is somewhat similar to buckling of

Visualization Module (Post processing)

to see the results.

shape of SPSW1

in

Step Transverse Load.

out-of plane deformation (due to fabrications). So the of plate )

(37)

−

Now we will see the

deformed shape

(This step is static push over . Here out of plane deformations load, and the buckling along the compression diagonal

shape of SPSW1 at the end of analysis)

Visualization Module (Continued)

shape of SPSW1

in

Step Lateral Load.

deformations start increasing with increase in lateral diagonal can be very clearly seen from the deformed

(38)

Visualization Module (Continued)

−

If we look at

Von Mises stress distribution

Visualization Module (Continued)

(39)

Visualization Module (Continued)

Here we will create X-Y plot

First plot is of

Horizontal component of Total

increment

Creating X

Visualization Module (Continued)

Force developed at bottom extreme node vs

(40)

Visualization Module (Continued)

Selection of bottom extreme nodes to create X

Visualization Module (Continued)

(41)

Visualization Module (Continued)

(42)

Similarly create plot of

Horizontal displacement (U1) of top node

Visualization Module (Continued)

Horizontal displacement (U1) of top node vs increment

Visualization Module (Continued)

(43)

− Now we will create a plot of Base shear (which force developed at extreme bottom nodes displacement of Top node

Visualization Module (Continued)

(which is sum of horizontal component of total nodes (which are fixed support)) and lateral

(44)

About ABAQUS Command line use (Input file creation )

Note:-

All models are called

input files

.

•An

input file

has two sections;

Model

and

•The

Model

section contains all the information

the history section.

•The

History

section is what you do to the

•The

History

section is what you do to the

•Input files have a .

inp

extension and can be

Now we will discuss how to create the

file and then we will run it through

through ABAQUS CAE

About ABAQUS Command line use (Input file creation )

History

information about the model and comes before

model. You work on the model in

Steps

.

model. You work on the model in

Steps

.

be created in any ASCII (text) editor.

the model SPSW1 through an input

through windows command prompt or

(45)

Simple Input File (Model Section)

**The lines starting with ** (2 asterisks)

**ABAQUS solver. Other lines beginning with

******************************************************************************

*Heading SPSW1

*Preprint, echo=YES, model=YES, history=YES,

******************************************************************************

**The *PREPRINT key controls what information **SPSWl.dat. Here, we have asked ABAQUS

**SPSWl.dat file is rather large as a consequence **you can set all the options to NO to reduce

******************************************************************************

** (Creating geometry of model)

****************************************************************************** ****************************************************************************** ** PARTS

*Part, name=PART-1-1

******************************************************************************

** (Defining the control node coordinate)

****************************************************************************** *NODE 1, 0., 0., 0. 21, 3, 0. 0. *NGEN, nset=bottom 1, 21, 1 ******************************************************************************

**(nset=bottom is a node set which contains **interval of 1)

****************************************************************************** *NCOPY, CHANGE NUMBER=420, OLD SET=bottom,

0, 3, 0

Simple Input File (Model Section)

asterisks) commented and are ignored ** by the with a single * denotes an ABAQUS keyword.

******************************************************************************

history=YES, contact=YES

******************************************************************************

information is printed to the file named to print out absolutely everything. The consequence. Once the input file is correct, reduce the size of the file.)

****************************************************************************** ****************************************************************************** ****************************************************************************** ****************************************************************************** ****************************************************************************** ******************************************************************************

contains node started from 1 to 21 with an

****************************************************************************** SET=bottom, SHIFT, new set=top

(46)

*NFILL bottom, top, 20, 21 *Element, type=S4R 1, 1, 2, 23, 22 21, 22, 23, 44, 43 ******************************************************************************

**(Generating the intermediate shell elements

****************************************************************************** *ELGEN, elset=bottom 1, 20, 1, 1 *ELGEN 21, 20, 1, 1, 19, 21, 20 ******************************************************************************

** (Creating master elements by using *Element

****************************************************************************** *Element, type=B31 *Element, type=B31 500, 1, 2 1000, 421, 422 1500, 1, 22 2000, 21, 42 *ELGEN, elset=beam 500, 20, 1 1000, 20, 1 1500, 20, 21 2000, 20, 21 ******************************************************************************

**(By using *Elset command one can made **will be helpful while assigning material **etc.)

****************************************************************************** ******************************************************************************

elements in increment through *ELGEN command)

******************************************************************************

*Element command.)

******************************************************************************

different set or group of element which material properties,boundary conditions,loading

(47)

*Elset, elset=BEAM 500, 501, 502, 503, 504, 505, 506, 513, 514, 515 516, 517, 518, 519, 1000, 1001, 1002 1009, 1010, 1011 1012, 1013, 1014, 1015, 1016, 1017, 1018 1505, 1506, 1507 1508, 1509, 1510, 1511, 1512, 1513, 1514 2001, 2002, 2003 2004, 2005, 2006, 2007, 2008, 2009, 2010 2017, 2018, 2019

*Nset, nset=_PICKEDSET2, internal, generate

1, 441, 1

*Elset, elset=_I1, internal, generate

1, 400, 1

500, 519, 1

1000, 1019, 1

1500, 1519, 1

2000, 2019, 1

** Region: (Section-1-_I1:Picked) *Elset, elset=_I1, internal, generate

1, 400, 1

** Section: Section-1-_I1

*Shell Section, elset=_I1, material=Steel 0.0025, 5

******************************************************************************

**(*Shell section command will create shell no. of integration point)

****************************************************************************** , 507, 508, 509, 510, 511, 512, 1002, 1003, 1004, 1005, 1006, 1007, 1008, 1018, 1019, 1500, 1501, 1502, 1503, 1504, 1514, 1515, 1516, 1517, 1518, 1519, 2000, 2010, 2011, 2012, 2013, 2014, 2015, 2016, generate ******************************************************************************

section having thickness =0.0025m with 5

(48)

** Region: (Section-2-_I5:Picked), (Beam *Elset, elset=_I5, internal, generate

500, 519, 1

** Section: Section-2-_I5 Profile: Profile

******************************************************************************

** (*Beam section command will create beam

****************************************************************************** *Beam Section, elset=_I5, material=Steel,

0.0381, 0.0762, 0.059182, 0.059182, 0.006604 0.,0.,1.

1000, 1019, 1

** Section: Section-3-_I2 Profile: Profile

*Beam Section, elset=_I2, material=Steel, *Beam Section, elset=_I2, material=Steel, 0.0381, 0.0762, 0.059182, 0.059182, 0.006604 0.,0.,1.

1500, 1519, 1

** Section: Section-4-_I3 Profile: Profile

*Beam Section, elset=_I3, material=Steel, 0.0381, 0.0762, 0.059182, 0.059182, 0.006604 0.,0.,-1.

2000, 2019, 1

(Beam Orientation:Picked) Profile-1

******************************************************************************

beam of I-cross section)

****************************************************************************** material=Steel, temperature=GRADIENTS, section=I

006604, 0.006604, 0.004318 (Beam Orientation:Picked)

Profile-2

material=Steel, temperature=GRADIENTS, section=I material=Steel, temperature=GRADIENTS, section=I

006604, 0.006604, 0.004318 (Beam Orientation:Picked)

Profile-3

material=Steel, temperature=GRADIENTS, section=I 006604, 0.006604, 0.004318

(49)

** Section: Section-5-_I4 Profile: Profile *Beam Section, elset=_I4, material=Steel, 0.0381, 0.0762, 0.059182, 0.059182, 0.006604 0.,0.,-1.

*End Part

******************************************************************************

** (Used to assemble the different individual part is used.)

****************************************************************************** ** ASSEMBLY

*Assembly, name=Assembly

*Instance, name=PART-1-1, part=PART-1-1 *End Instance

**

*Nset, nset=topnode, instance=PART-1-1 431

431

*Nset, nset=_PICKEDSET11, internal, instance=PART 421, 422, 423, 424, 425, 426, 427, 428

441

*Nset, nset=_PICKEDSET13, internal, instance=PART 221,

*Nset, nset=_PickedSet8, internal, instance=PART 1, 21

*Nset, nset=_PickedSet9, internal, instance=PART

2, 3, 4, 5, 6, 7, 8, 9, 10 18, 19, 20, 22, 42, 43, 63, 64, 168, 169, 189, 190, 210, 211, 231, 232, 336, 337, 357, 358, 378, 379, 399, 400, 428, 429, 430, 431, 432, 433, 434, 435, Profile-4

material=Steel, temperature=GRADIENTS, section=I 006604, 0.006604, 0.004318

******************************************************************************

individual parts here in current problem only one

****************************************************************************** instance=PART-1-1 428, 434, 435, 436, 437, 438, 439, 440, instance=PART-1-1 instance=PART-1-1 instance=PART-1-1 10, 11, 12, 13, 14, 15, 16, 17 84, 85, 105, 106, 126, 127, 147, 148 252, 253, 273, 274, 294, 295, 315, 316 420, 421, 422, 423, 424, 425, 426, 427 436, 437, 438, 439, 440, 441

(50)

*Nset, nset=_PickedSet10, internal, instance=PART 2, 3, 4, 5, 6, 7, 8, 9, 10 18, 19, 20, 421, 422, 423, 424, 425, 426 434, 435, 436, 437, 438, 439, 440, 441 *End Assembly ******************************************************************************

** (With this Geometry of model ends)

****************************************************************************** ** MATERIALS

******************************************************************************

** (*Material command is used to define **different component of model It include **material) ****************************************************************************** *Material, name=Steel *Elastic 2.0e+11, 0.3 2.0e+11, 0.3 *Plastic 2.50+08, 0. ****************************************************************************** ** BOUNDARY CONDITIONS ******************************************************************************

** (*Boundary command is used to create appropriate

****************************************************************************** ** Name: Disp-BC-1 Type: Symmetry/Antisymmetry/Encastre

*Boundary

_PickedSet8, ENCASTRE

** Name: Disp-BC-2 Type: Displacement/Rotation *Boundary _PickedSet9, 3, 3 *Boundary _PickedSet10, 2, 2 instance=PART-1-1 10, 11, 12, 13, 14, 15, 16, 17 426, 427, 428, 429, 430, 431, 432, 433 ****************************************************************************** ****************************************************************************** ******************************************************************************

define material which has been used to include all engineering properties of

******************************************************************************

****************************************************************************** ******************************************************************************

appropriate boundary **conditions)

****************************************************************************** Antisymmetry/Encastre

(51)

** STEP: Transverse load

******************************************************************************

** (*Step command is used to create

**General, Static Riks, Dynamic, Dynamic

one can define corresponding loading on model)

****************************************************************************** *Step, name="Transverse load ", nlgeom=YES

******************************************************************************

**(nlgeom=YES means geometric nonlinearity **deformations)

****************************************************************************** *Static

1., 1., 1e-05, 1. ** LOADS

Simple Input File (History Section)

** LOADS

** Name: CFORCE-1 Type: Concentrated force

******************************************************************************

**(*Cload command is used for concentrated node i.e._PICKEDSET13 in negative z-direction plate ) ****************************************************************************** *Cload _PICKEDSET13, 3, -2. ** ** OUTPUT REQUESTS

*Restart, write, frequency=0

******************************************************************************

**(*Restart command in ABAQUS allows multi **frequency=n that means saving the output

**directly give output at end of step without

**frequency=0 means to save output for each interval)

****************************************************************************** ******************************************************************************

different analysis step like Static

Explicit etc. In each analysis **step model)

****************************************************************************** nlgeom=YES

******************************************************************************

nonlinearity is on to account for large

******************************************************************************

Simple Input File (History Section)

force

******************************************************************************

load. A load of 2N is applied at middle direction to initiate initial imperfection in

******************************************************************************

multi step analysis. Here one can use after n interval,frequency =overlay means without saving intermediate increment result,

interval)

(52)

** FIELD OUTPUT: F-Output-1 *Output, field

*Node Output CF, RF, TF, U

** FIELD OUTPUT: F-Output-2

*Element Output, directions=YES

E, ESF1, MISESMAX, NFORC, PE, PEEQ, S, SE, ** HISTORY OUTPUT: H-Output-1

*Output, history, variable=PRESELECT *End Step

****************************************************************************** ** STEP: Lateral load

*Step, name="Lateral load", nlgeom=YES,

******************************************************************************

**(In “Static Riks” step 0.1 indicate initial

**period of step 1e-10 indicate minimum

**maximum time increment allowed 20 indicates

**topnode, 1, 0.05 indicates the displacement **x- directional displacement reached up

****************************************************************************** *Static, riks

0.1, 100., 1e-10, 1., 20., topnode, 1, 0 ** LOADS

** Name: CFORCE-2 Type: Concentrated force

******************************************************************************

**(A load of 10000N is applied at

**positive x-direction for static pushover

****************************************************************************** *Cload _PICKEDSET11, 1, 10000. SE, SEE, SF ****************************************************************************** inc=10000 ******************************************************************************

initial time increment 100 indicate time

minimum time increment allowed 1 indicate

indicates load proportionality factor, displacement control means stop analysis when

up to 0.05m)

****************************************************************************** 0.05

force

******************************************************************************

top edge nodes i.e._PICKEDSET11 in pushover analysis.)

(53)

** OUTPUT REQUESTS

*Restart, write, frequency=0 ** FIELD OUTPUT: F-Output-3 *Output, field

*Node Output CF, RF, TF, U

** FIELD OUTPUT: F-Output-4

**************************************************************************

** (Field output will give the selected

************************************************************************** *Element Output, directions=YES

E, EE, ESF1, IE, MISESMAX, NFORC, PE, ** HISTORY OUTPUT: H-Output-2

*Output, history, variable=PRESELECT *End Step

To run

ABAQUS Input File on Command Prompt

• At the command line

abaqus job=filename int

(say SPSW)

**************************************************************************

selected output)

************************************************************************** PEEQ, S, SF

ABAQUS Input File on Command Prompt

(say SPSW)

(54)

Output Files created during running an Analysis

Following files were created during running

C:\Temp\Tutorial\SPSW1)

SPSW1.odb:-Out put database file which contains all for given job.

SPSW1.dat:-This file contains all kinds of information

In particular, if ABAQUS encounters any problems during will be written to this file.

SPSW1.log:- You will see some information about

execution. You should also see that the file ends with ABAQUS JOB SPSW1 COMPLETED ABAQUS JOB SPSW1 COMPLETED

SPSW1.res:-The file named SPSW1.res is called a

file contains full information about the analysis. The restart element mesh, or contours of stress, displacement, etc

SPSW1.sta:-This file is continuously updated by ABAQUS

computation has been completed.

SPSW1.msg:-The file named SPSW1.msg contains

used, the iterative process, and the tolerances that solution has converged.

SPSW1.fil:-The file named SPSW4.fil is called a `results

file contains data that were specifically requested in the

Output Files created during running an Analysis

an analysis in a directory of job file (say

all requested field output and history output database

information about the computations that ABAQUS has done. during the computation, error and warning messages

about the time it took to for ABAQUS to complete with

`restart file’ (the file always has .res extension). This restart file is most useful if you want to plot the finite etc

ABAQUS as it runs, and tells you how much of the

contains much more information concerning the increments that ABAQUS has applied to determine whether a

`results file’ (the file always has a .fil extension). This the ABAQUS input file.