Introduction to Samcef Bacon command -...

11-01-2013<author> LMS Samtech

Introduction to Samcef Bacon command

Liege 17 April 2013

Crouzier Régis LMS Samtech

LMS Samtech Division Copyright LMS International - 2013

Chapters

� Chapter 1: What is Bacon ?

� Chapter 2: Language syntax

� Chapter 3: What is a model ?

� Chapter 4: The mesh

� Chapter 5: Groups of nodes/elements/…

� Chapter 6: Mathematical model

� Chapter 7: Material

� Chapter 8: Physical properties

� Chapter 9: Loads and boundary conditions

� Chapter 10: Pre-processing, check data

� Chapter 11: Post-processing

2


(I1) What is Bacon ?

� Bacon is the pre & post processing module of the Samcef suite.

� It reads instructions from the keyboard or a bank file.

� The instructions are structured in a command language.

� How to start Bacon from a terminal/ Dos shell :

samcef ba name y|n 1|2|3

name name of the problem -> bank file=name.dat

y|n use or not optional files

1|2|3 foreground | background |batch execution

3


(I2) Bacon as pre-processing module

Others …

BACON

Bank Files

FEM data

IGES cad

Keyboard

Name.sdb

Name.samANALYSIS(ASEF,…)

Name_xx.u18Neutral file

Nastran Bulk

Name.spy

4


(I3) Bacon as post-processing module

Excel.csv

BACON

Bank Files

Keyboard

Name.sdb

Name_xx.u18

FAC

Name_xx.fac

Name_xx.des

ImageJpeg, ps

Name.spy

5


(I4) Bacon most important related files

� *.spy Spy file (MODE M)

*.sam Prepared data for computation

*.dat Bank file

*.sdb Database

*_yy.des & *_yy.fac Prepared results files (produced by the FAC program)

bacon.ini Initialisation file (located in the home directory; "bank file" like)

6


(L1) Language syntax

� .NOEUDS I 1 X 10.0 Y (44*12) Z (/myz)

�MODE LECTURE 512

� max 512 characters per input line (see $)

� lowercase or UPERCASE, no matter...

A point in column 1

3 significant characters

Parameters Values

Start in column 1

4 significant characters

Mixed of French and English in the names of the commands & parameters.

7


(L2) Language syntax

� For each command, a set of allowed parameters

� Some parameters have default values, other not !

� See online help for more details

� A blank between the command name and the 1st parameter:

� .NOE I 1 ....

� .NOEI 1

� A blank between a parameter and its value :

� .NOE I 1 X 10

� Other extra blanks are ignored

8


(L3) Syntax command: special characters

� &� comment the whole line

• This is a commented line &

• .NOE I 1 X ...

� !� comment the end of the line

• .NOE I 1 X ... ! my first point

� ;� split line

• .NOE I 1 X 1 ; vi ; I 2 X 2

� $� continuation line ; to divide a input line greater than 512 characters or to give a better

layout to a bank file

• .NOE I 1 $X 1 $Y 1

� (..)

� expression to evaluate

• .NOE I 1 X (44*32)

9


(L4a) 1st type of command: . XXX

� Point in column 1

� Standard command.

� When invoke :

� close the previous command,

� flush data created/modified/computed

� and then....

� (Nearly all of these commands do it)

(a) load the mesh

(b) initialize internal data

Time consuming !

10


(L4b) Some important .XXX commands

� .NOE, .MAI, .EXT, .CMA Manual mesh

.POINT, .DROITE....

.GENCAD meshing

.MAT, .AEL Material definition

.PHP Physical properties

.CLM, .CLT Loads & Boundary conditions

.SUBCASE, .SAM Computation strategy managment

.SAUVE BANQUE Saving the model in a structured format

.FIN Preparing the model for computation

11


(L5a) 2nd type of command: ABC

� No point in column 1

� Command keyname must start in column 1

INPUT Read bank file INPUT "mesh1.dat”

RETURN (CLOSE)

Stop reading and return to the calling file

.NOE ...

...RETURN

EXIT Stop reading and returned to the keyboard

.NOE ...

...EXIT

GRAP Graphic attribute GRAP NOE

12


(L5b) 2nd type of command: continued

� ABRE Abbreviationdefinition

ABRE "/myz” "33.33”

MODE Operating mode MODE LECTURE 256

ASSIGN I/O file assignation

TITRE TITLE TITRE "Hello World”

....

13


(L6a) INPUT and the bank files

� What are bank files ?

� Bank files are «<name>.dat» files where models (or part of models) are described.

� They are loaded through the INPUT command.

BACON

INPUT.NOM "file.dat" .NOM & .NOE ...………EXIT

file.dat

optional«jump to» point

14


(L6b) INPUT and bank files (continued)

� Cascading INPUT

BACON

INPUT.NOM "file"

.NOM (optional)INPUT "FILE2"……INPUT "FILE3"…

…

EXIT

………RETURN

………RETURN CLOSE

file.dat file2.dat

file3.dat


(L6c) INPUT .... (continued)

� INPUT "..... " FILTRE

� FILTRE: ignore keywords define in the MODE FILTRE "...." command

� By default, ignore "VISUALISE;DPOINT;DIGIT"

� Usefull when reading a spy file:

• INPUT "geo.spy" FILTRE

� INPUT "..." ONLY

� Restrict reading action to specific commands

A current loaded bank file cannot be edited while BACON is running

16


(L7a) Two different bank files

� Your own «freely structured» bank file

The Bacon structured bank file; defined fixed format

.NOE I 1 X 1.5 ....

...

.MAI I 1 ...

....

.NOE I 11 ...

...

. MAT I 1 ..

...

.MAI I 100 ...

...

.NOE I 1 X 1.5000E00...I 11 ......

.MAI I 1 N .......I 100 .......

.MAT I 1 ...

17


(L7b) bank files in Sfield

�

18


(L7c) bank files in Sfield

�

19


(L8a) ABRE: defining abbreviations

�ABRE "/ myabre" "value"

� ABRE "/myx" "33.33".NOE I 1 X /myx

Keyword Definition

Abbreviation tag

Field locator Unique for all abbreviationsUse / or % only

The definition is a string, even if it only contains a

number

Use " or ' only." preserves the case

20


(L8b) ABRE: use

� The abbreviation is evaluated when used

� ABRE "/myx" "33.33".....NOE I 11 X /myx...INPUT "a.dat"....NOE I 1000 X /myx

ABRE "/myx" "33.33"ABRE "/mytt" "/myx-33"....NOE I ... Y (/mytt+2.1)

…ABRE "/myx" "44" ………RETURN a.dat

33.33

44

Question: what does /mytt content here ?

21


It's now to you to play

�

22


(Ex1a) 1st exercice

� Build a 5 X 5 elements XY squared mesh

� The plate has a size of 1000*1000 mm

� Build the geometry using the command : .point, .droite

� Build the mesh at degree 1using the command : .cont, .dom, .gen

See online doc for details about the commands

23


(Ex2a) 2nd exercice

� Same as exercice 1 but parameterize through abbreviations the points coordinates:

Using Abbreviations.

24


(L10a) Force evaluation of abbreviations

� Why ?

� We saw that abbreviations are only evaluated when used.

� Sometimes it may interesting to evaluate it and to continue themodel with the new value

• ABRE "/myabre" "/a+/b-/c........"

• ABRE "/myabre" " ' '/myabre' "

� Sometimes, force evaluation is compulsory

� ABRE "/myvalue1" "1.1"

� ABRE "/myvalue" "2.2+/myvalue"

� ECHO "This is /myvalue"

� Echo "This ' '/myvalue' "

This is /myvalue

This is 3.3

' '/myabre'

Single quotes !

25


(L10b) Force evaluation of abbreviations

� .DEL.*

� ABRE "/DX" "1.0"

� ABRE "/DY" "1.0"

� ABRE "/MYABRE" "/DX -3*/DY"

� ABRE "/MYABRE"

� .NOE I 1 X (/MYABRE)

� ABRE "/MYABRE" "''/MYABRE'"� ABRE "/MYABRE"

/DX - 3*DY

X = -2.0

-2.0

26


(L11) Mathematical operations in (...)

� Basic: +, -, *, /, :, **

� Math SIN sine function

COS cosine function

TAN tangent function

ASIN inverse sine function

ACOS inverse cosine function

ATAN inverse tangent function

LOG logarithm (base 10)

LN neperian logarithm

ABS absolute valueINT integer part

NINT nearest-integer function

SQR square root

MIN minimum value

MAX maximum value

PI the 3.1415... constant

MOD(a,b) modulo function

SIGN(a,b) abs(a) with sign of b

27


(L14) The spy file

� <problem_name>.spy

� Records every action

� Driven by MODE M <value>

� MODE M -1 ! spy file disable

� MODE M 1 ! reduced spy file (INPUT keystroke ignored, ...)

� MODE M 2 ! full spy file (default)

The spy file cannot be edited while BACON is running

28


(L15a) MODE TRACE

� Log information in an external text file

� MODE TRACE "trace.txt"...LIST...ECHO "..."...MODE TRACE 0...MODE TRACE......MODE TRACE 0CLOSE "trace.txt"

Start log

Switch log on/off

Close log file

29


(L15b) MODE TRACE (continued)

� !***TRACE Bacon number 1 on file (42)***

Trace file : 42 - /directory/file.txt"

!***TRACE Bacon number 2 on file (42)***

### NODES 1 AND 2 ###

!***TRACE Bacon number 3 on file (42)***

I 1 X 1.00000E+00 Y 1.00000E+00

I 2 X 2.00000E+00 Y 2.00000E+00

Number of listed nodes = 2

Each command have its own format for listing data

Not all commands can list data !

30


End of first part

�

31


(MO1) What is a model ?

� A model contains

� a mesh

� a mathematical model for the elements behavior

� materials & physical properties

� loads & boundary conditions

� a computation strategy

� Except for beams, no units system has to be set up.

You have to ensure a consistent units system by your own


(ME1) The mesh: automatic mesher

�

Points.POI .3PO Surfaces

.PLAN .RULED.COONS .NURBS

Line Domain .DOM

Open Contour .CON

Close Contour .CON

Surface Domain .DOM

Volume Domain .FACE .VPEAU .DOM .BOX

Mesher.GEN

Lines.DRO .3DR .ARC .3ARC .SPL

.3SPL .ELL .LIM .3LI


(ME2) The mesh: automatic mesher (continued)

� + basic tools too manipulate CAD entities

� + several mesher in .GEN

� Pavor, triangle

� transfinite

� LUI

� ...


(ME3) Tools to improve the mesh

� .LIS: improve automatic meshing

� .EXT: extruding a 2D mesh

� .CMA copying/moving meshes


(GR1) Groups

� Groups of nodes, elements, faces

� .SEL GROUP <id> <type_keyword> (NOM "...")<selection>

� Ex: .SEL GROUP 8 MAILLES NOM "myfirstgroup"

No blend !

NOEUDS for nodesMAILLES for elements

FACES for faces

There is no way to select edges of

volumes

edges of 2D elements are selected with theFACES keyword


(GR2) Groups (continued)

� <selection>

� I - J - K - ! loop on ids

� BOITE ... ! box

� TOUT

� ORIENTATION ...

� Example

• .SEL GROUP 1 MAILLBOITE CYLINDER 4 4 RAYON 5

GROUPE 2 NOEUDSTRANSFORM 1


(GR3) Groups (continued)

� Group edition

� UNION, DIFFERENCE, ...

� TRANSFORM from one type to another

� add / remove individual entities

� ...etc


(HYP1) Mathematical model: .HYP

� .HYP <keyword><selection><selection>......

Keyword

MINDlin 21 22 28 29 8 46 47

VOLUmic 151 22 57 58 8 46 47

One keyword for one family of elements

SAMCEF element type id

Topology


(HYP2) .HYP (continued)

� <selection>

� I - J - K -

� ATT -

� GROUP –

� Example: .HYP VOLUME

� volume T8, T46, T47

� membrane T57, T58

� rod



� Example: .HYP MINDLIN (shells)

� T28 et T29

� .AEL EXCE -

Exce>0



�


(MAT1) Material

�

� .MAT I <id> (NOM "...")<behaviour>


(MAT2) Material (continued)

� <behaviour>: example

� BEHAV "Elastic"

YT - ! Young modulus

NT - ! Poisson ratio

A - ! Thermal expansion coefficient

KIRCHOFF (BIOT) (CAUCHY) ! Stress / strain measurement

......

� Attached to elements

� .AEL <elements_selections> MAT <matid> or "<mat_name>"


(PHY1) Physical properties

� .PHP: to define thicknesses of shells and membranes

� PHP THICK <elements_selection> VALUE <thickness_value>

� <elements_selection>

• I - J - K - explicit list

• TOUT

• GROUP group_id or GROUP "group_name"

• ATT cells attributes

• ...

� <thickness_value>

• one average thickness on the element

or

• as many thicknesses as element's vertices


(PHY2) Physical properties (continued)

� Exemple

� PHP THICK GROUP "bottom" VALUE 1.12

� LIST, VI, .. facilities to control the data



� Element axes basics: .FRAME + .AEL .. FRAME ...

� (A) Volume:

� default axes =structural axes

� Tuned axis: .FRAME . .. + AEL .. FRAME -



� (B) Shell

� Default axes:

� 1st axis = edge 1->2 of the element

� 3rd axis = the normal to the element

� 2nd axis = cross product of the two above

� Tuned axes: .FRAME . .. + AEL .. FRAME - THETA -



� (C) Volumic shells

� (D) Composite

� see online help

� .FRAME I - TYPE - ORIGIN - - - V1 .. V2 .. V3 ..

Type of frame: cartesian, cylindrical, ... Axes definition:- cosine- points- nodes

- ..


(LBC1) Loads & Boundary conditions

� .CLM/.CLT

� .CLM <what> <where> <values>

� Check: VI, LIST, ...

Type of loads:- pressure (PRESS)- nodal loads (CHA)

- ...

Type of boundary conditions:- clamps (FIX)

- prescribed displ. (DEP)- ...

Support:NOEUDS

ELEMENTSFACESGROUP

....

Values:VAL - NC -

VAL - TIME -VAL NF - TIME

Check in the online help which load an type of

element is able to undergo: CLM/CLT commands do

not check it !


(LBC3) Loads & Boundary conditions

� Local axes on nodes

� .AXL I - FRAME -

� Nodal forces applied on nodesfollow local axes definition


(DES1) Pre-Processing – Check data

� Check the mesh : .DES

� Check the mesh

• Select elements by groups

• Selection by type (quadrangle – triangle –hexa –penta …..)

� Check axl / isotropic material /….

� Visualise mesh (see grap command)

� Check boundary conditions : .CLM/.CLT



�


(Ex3a) 3rd exercise

� Load the "ex03-mesh.dat" file and defines:

� a MINDLIN hypothesis to all the elements

� a simple Elastic material (Young and Poisson's ratio) using the given abbreviations; attached this material to all the elements

� a thickness for all the elements using the given abbreviations

� Tip: use online help for all the commands parameters


(Ex3b) 3rd exercice

� .HYP MINDLIN

� .MAT I 1

� BEHAV "Elastic"

� Yt (/Young)

� Nt (/nu)

� .SEL GROUP "E_All" MAILLE TOUT

� .PHP GROUP "E_All" THICK VAL (/T)

� .AEL GROUP "E_All" MAT 1


(Ex4a) 4th exercice

� Use the completed exercice 3 bank file to define the boundary condition:

� all the nodes on the edges of the plate must be clamped

� Tip: use .SEL BOITE to define a group of nodes for eachedge and use .SEL UNION to merge the 4 elementarygroups into a new one

� Define the load: a uniform pressure (see abbreviation) pushing on all the elements

� Pay attention to the normal to the shells - toward which a positive pressurewill act- to setup the correct sign of the pressure


(Ex4b) LBCs

� .SEL

� GROUP "Left" NOEUD boite stru xi 0 yi 0 xs 0 ys /Ly

� GROUP "Right" NOEUD boite stru xi /Lx yi 0 xs /Lx ys /Ly

� GROUP "Bottom" NOEUD boite stru xi 0 yi 0 xs /Lx ys 0

� GROUP "Up" NOEUD boite stru xi 0 yi /Ly xs /Lx ys /Ly

� GROUP "Boundary" UNION "Left" "Right" "Bottom" "Up"

� .CLM GROUP "Boundary" FIX COMP 1 2 3 4 5 6

� .CLM GROUP "E_All" PRES VAL (-/Press) NC 1


End of second part

�


(POST1) Post-processing

Excel.csv

BACON

Bank Files

Keyboard

Name.sdb

Name_xx.u18

FAC

Name_xx.fac

Name_xx.des

ImageJpeg, ps

Name.spy


(POST2): Post-processing

� After the computation, the FAC program is launched to create two results files

� <problem_name_xx.des> & <problem_name_xx.fac>

� xx is a two characters shortcut of the launched computation program:

• "as" for ASEF, "me" for MECANO, ..


(POST3): Post-processing

� (1) Reload the database

� .DOC DB "<problem_name.sdb>

� (2) Attached the results files

� ASSIGN FAC "problem_name_xx"

� Two main commands for post

� .DES

• classical structural results

� .VIF

• time/frequency results curves


(DES1): a result = code + references

� In .DES, a result is defined by a code and some references

� the CODE is the label of a result

� the REFERENCES are couple of attributes attached to the code; theydefined to which loadcase/frequency/timestep/complex_phase...the code is attached to

• Example, after a static computation with two loadcases, we have,for instance, the following displacements results

code 163 reference 4 1

code 163 reference 4 2

163 means displacements4 means loadcase

1st loadcase

2nd loadcase


(DES2) Example of codes

� 163 Displacements

1411 At nodes by elements (extrapolated) stresses

1310 At nodes by elements (extrapolated) Vonmises equivalent stress

3310 By elements Vonmises equivalent stress

1511 Thermal conductive flux (vector at nodes by elements)


(DES3): Different types of codes

� By nodes

� scalar: temperature, ..

� vector: speed, ..

� displacements

� By elements

� scalar: Vonmises, composite criteria, ..

� vector: thermal flux, ..

� tensor: mean stress/strain tensor, ..

� At nodes by elements

� scalar: extrapolated Vonmises, ..

� tensor: extrapolated stresses/strains, ..

Depending on the run analysis, a set of default results code is generated


(DES4): Code 1xxx, 3xxx ??

� 1435 Stress tensor obtained by extrapolating stresses from Gauss Points to nodes. We have a tensor at nodes by element

3435 Mean Stress tensor: from Gauss Points stresses and using Gauss Points Weights, we compute a true mean value. We have a tensor by element

1331 Vonmises equivalent stress obtained by extrapolating VM stresses from Gauss Points to nodes. We have a scalar at nodes by element

3331 Mean Vonmises equivalent stress: from Gauss Points VMs and using Gauss Points Weights, we compute a true mean value. We have a scalar by element


(DES5a): Code 1xxx vs 3xxx

�

Bending clamped shell


(DES5b): Code 1xxx vs 3xxx

�

Rough stresses computed at Gauss points and extrapolated to nodes, then Vonmises

criteria

--> discontinuities

Rough Vonmises criteria computed at Gauss points and extrapolated to nodes

--> discontinuities


(DES5C): Code 1xxx vs 3xxx

�

Rough VonMises computed at Gauss points), then a mean value computed at the center of

the element

Rough stresses computed at Gauss points), then a mean value computed at the center of

the element, then VonMises criteria

show that mean stress in the middle of the structure is computed as nearly zero


(DES6) Examples of references

�

� A code can handled several couples of referencesif needed

4 loadcase

8 timestep

11 Fourier analysis

6 vibration eigenmode

...

Transient analyses use 'timestep'

instead of 'time' for accessing results


(DES7): Loading a result code

� CODE xxx REFERENCE r n (k l ...)

� example : code 163 ref 4 2

� as long as they are not changed, references remain activefor every code reloaded

� For each reloaded code, there is a set of parameters to extract derivated results, like module of the displacements, amplitude of a vector, criteria on a stress tensor, ...

� but it is quite impossible here to describe all of them


(DES8a): ISO and DISCONTINUITY

� ISO: to transform element average values to nodal values

� DISC: to smooth extrapolated values

ISO 1

ISO 0

DISC 0

DISC 1


(DES8b): ISO and DISCONTINUITY

�

SCALAR / NODE / ELEMENT SCALAR / ELEMENT

SCALAR / NODE

ISO 0

MOYENNE

ISO

DISC 0

DISC


(DES9): Sections

� SECTION

L1

L2

L3

L4

SECTION LIGNE 1 2 3 4

LSECTION …

SECTIONNearest nodes

(from cad)

LSECTION …Projection on shell or

interpolation in the volume for n points


(DES10): Operations on codes

� Operations on codes

� DEPL COMP 1 MEMO 1DEPL COMP 2 MEMO 2OPERATION "$1-$2"

� CODE - REF - - FACTEUR aCODE - REF - - FACTEUR B ADDITION

Operations on scalar at nodesor

scalar at nodes by elements.Result will always be a

scalar at nodes by elements

To combine two codes as

a * code_1 + b * code_2


(DES11) Reduced list of elements

� In a model in which several types of elements are mixed (for instance shells & volumes),results codes are attached to a reduced list (set) of elements.

� For instance, upper skin stress tensor is only attached to theshells, volumic stress tensor to volumes, ..

� These reduced are automatically handled when a code is reloaded.

� As a consequence, reloaded code is only displayed on relevantelements while others are transparent


(SAI1): Results selection

� .SAI ARCHIVE <where> STYPE <result_code>

� <where> can be an element selection, a node selection orSTRUCTURE

� <result_code>

� example

• .SAI ARCHIVE STRUCTURE STYPE 1411



�


(Exe7): Post-processing

� Model:

� square 400mm X 400mm Mindlin shells plate (16 elements on each side)

� thickness of 2 mm

� Classical steel material (Yt=210000 MPA)

� Structure clamped on its edges

� Uniform pressure of 0.01 Pa on the whole structure

� (.SAI) Force archiving following results:

• (stress tensors) 1431, 1435, 1436, 3431, 3435, 3436

• (vonmises) 1310, 1331, 1332, 3310, 3331, 3332

� ASEF computation


(Exe7) Post-processing

�

� code 163 mod depl;vi



�

� grap div clot 2 vert; grap selec clot 1; code 3331; vigrap selec clot 2; code 1435;vonmises;vi



�

moyenne



�

iso



�

� grap reset cloture; code 1435; vonmises; vi



�

� discont 0; vi



� liste desc


(Exe8): Adding new results codes

�


�


�

These are the default computed stress results


�


End of 4th part

�

11-01-2013<author> LMS Samtech

Thank you

Introduction to Samcef Bacon command -...

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