Advanced Modeling in SAMCEFoss.jishulink.com/caenet/forums/upload/2014/12/16/396/...2005/08/11 · Contact problems (Type of contact, Algorithm description, data files, guide lines)

Advanced Modeling in SAMCEF

How to defines a FE problem with BACONExtended elements, Assembly, Advanced BC

March 2005

08/11/2005

Advanced Advanced Modelling in Modelling in

SAMCEFSAMCEF

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introduction! Lesson's objective

The goal of this lesson is to give an overview of most of the data necessary to make a FE model.

In principal we will see:" Structural elements and their properties" Special elements: their field of application and the related

macro commands" The boundary conditions" Post-processing

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Table of Contents

1. Element description1. 3d volume (integration, internal mode, mid-face node)2. 3d Mindlin shell (Drilling mode, curvature, excentricity,…)3. Beam element (1d mesh, .BEAM .BPR )4. Axi hypothesis , Plane strain, Plane stress, Generalized Axi,

Generalized Plane strain5. Super-element technique (.CSU .USU .RSU)

2. Assembly modelling, flexible elements and mesh joining1. Description and use of elements MCE (BUSH, RIGI, SPRI,

CNLI, PLAN, DIST, SPR1, HING, PRIF, MACR, POST)2. Joining of two mesh of different type or size (.STI .APS)3. Rivets modelling (.RI2)4. Macro commands (Rigid body .RBE Plane restriction .MPL)

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Table of Contents (cont)

3. Boundary conditions1. Conditions on nodes (CHA, FOL, DEP, … )3. Local axis (.AXL .FRA)4. Pressure, surface load of shells and volumes5. Visualisation and boundary conditions verification (I.e.

.CLM VI PRE ELEM TIME - VECT 0)6. Temperatures definition (.CLT)7. Mapping of pressure or other physical properties8. Pressure adjustment (.ADJ)9. Contact problems (Type of contact, Algorithm description,

data files, guide lines)

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Table of Contents (cont)

4. Post-processing1. Standard post-processing (.DES)2. Default and optional post-processing codes (.SAI)3. Results analysis (mean value, extrapolated values,

discontinuity, smoothing, …)4. Section in a volume, section along a line5. Use of .MNT for load balance (description and restrictions)6. Export of curve to Excel7. Result recovery with FEMPAD (SAMRES)

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Structural elements

! Structural element type are define by a mathematical hypothesis

! Function on this hypothesis and the geometrical topology the element type is given by

Example: among a lot of hypothesis, for 3d mesh

Keyword

MINDlin 21 22 28 29 8 46 47VOLUmic 151 22 57 58 8 46 47

.HYP keywords

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Structural elements

! By family: The volumes, type 8(11), 46(25), 47

.HYP VOLUME

.HYP COMPOSI VOLUME

Iso-parametric formulationDegree 1 or 2, possibility to have non uniform degreeFor hexahedron at degree 1, 9 additional incompatible modes are

added (better flexion) (To remove them: .AEL L 1)Tetrahedron at degree 1 are very poorBy default, 2x2x2 Gauss points for integration (To increase it

.AEL NG 3 3 3)For element in contact problem with degree 2, an additional node

is added in the middle of the face

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Structural elements

! By family: The membrane, type 57, 58

.HYP VOLUME

.HYP COMPOSI VOLUME

Iso-parametric formulationDegree 1 or 2, possibility to have non uniform degreeFor quadrilateral at degree 1, 4 additional incompatible modes are

added (better flexion) (To remove them: .AEL L 1)By default, 2x2 Gauss points for integration (To increase it

.AEL NG 3 3)Useful on the skin of volumes to improve stresses post-

processingBe careful with the mechanism

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Structural elements

! By family: The volume compatible rods 151

.HYP VOLUME

Iso-parametric formulation

Degree 1 or 2

Useful on the edges of volumes to improve stresses post-processing

Be careful with the mechanism

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Structural elements

! By family: The shells, type 28, 29

.HYP MINDLIN

Mindlin's shell theory

Mid-side nodes define the curvatures (no dof's on it)In the plane, 2x2 Gauss points for integration. In non-linear

material, through the thickness 5 GP (To increase it .AEL NG 2 2 10)

Possibility to offset the elementmid-plane (.AEL EXCE 10)

Be careful to the drilling dof's2 rigid body modes possible

Exce>0

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Structural elements

! By family: The rods and beams 21, 22

.HYP MINDLIN

Mindlin's shell theory

Compatible with Mindlin's shell element

Can be connected with volume elements (be careful with mechanism)

Mid-side nodes define the curvatures (no dof's on it)

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Structural elements

! By family: The 2d family 48(30),15,26

.HYP AXIS

MEMB BIDIM

…

Iso-parametric formulation

Degree 1 or 2, possibility to have non uniform degree

For quadrilateral at degree 1,4 additional incompatible modes are added (better flexion) (To remove them: .AEL L 1)

By default, 2x2 Gauss points for integration (To increase it .AEL NG 3 3)

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Structural elements

! The 2d family: several mathematical hypothesis.HYP AXIS GENE AXI

Tube under pressure Tube in torsionDisk in rotation 3 dof's per node

εεεεθθθθ = Ur / r σσσσθθθθ ≠≠≠≠ 0 εεεεθθθθ ≠≠≠≠ 0

Σ Σ Σ Σ Fr ≠≠≠≠ 0

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Structural elements

! The 2d family: several mathematical hypothesis.HYP MEMB BIDIM

General 2d membrane problems

σσσσz = 0 εεεεz = - ν ν ν ν ( εεεεx + εεεεy )

A thickness must be defined !

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Structural elements

! The 2d family: several mathematical hypothesis.HYP DEFO PLAN GENE DEFO PLAN

Infinite part (weight barrage) Long part Uz = Uz

εεεεz = 0 σσσσz = ν ν ν ν ( σσσσx + σσσσy ) Bending Uz = Cte * y

The thickness is equal to 1 εεεεz = Uz

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Structural elements

! The implicit degree 2" By default, Geometry degree and displacement field degree

are identical" To increase easily the accuracy, a mesh at degree 1 can

support degree 2 displacement fieldDof's are added to interface.SAM DEGRE 2 or .AEL DEGRE 2

" Must be taken into account in the boundary conditions.CLM CHA INT - - …

" Degree can be variable

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Structural elements

! Physical properties: ThicknessFor membrane or shell elements.PHP THICK element_selection VAL val

element_selection: I J K | ATT | GROUPE "…" | TOUT

Val: An average thicknessOne thickness by vertices

Check: VI or LIST

.PHP THICK TOUT VAL 1

THICK GROUPE "Hole" VAL 2

VI THICK

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Structural elements

! Physical properties: Thickness MappingGeneral feature for thickness, temperatures, pressure, …Needs 2 functions defined on nodes or points.FCT CREE FONCTION I 1

CREE VALEUR

POINT 1 2

ORDO 1 1

CREE FONCTION I 2

CREE VALEUR

POINT 4 5

ORDO 2 2

.PHP THICK TOUT MAP 1 2

VI THICK

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Structural elements! Physical properties: Element axis

" General rulesVolume Structural axisShell 1st axis from node 1 to node 2

" To change axis, use a predefined FRAME

" Other specific (old) rules .AEL LOCA COVO …" Useful for orthotropy or stress results

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Structural elements

! Physical properties: Beam definition" Mesh 1 d #### Rod elements

.NOE .MAI .DRO .CON OUVERT .DOM.GEN

" Give the orientation: rod #### Beam elements.BEAM "Element selection" "Orientation"

" Choose a unit system.UNIT (LENGTH) MM | METER | SI | …

" Define a beam profile.BPR NOM "myprofile" TYPE "I" dimensions

" Assign this profile to elements.AEL element_selection PROFIL "myprofile"

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Structural elements

! Physical properties: Beam definition" Mesh 1 d.POI I 1 X 0 Y 0.ARC CENTRE 1 RAYON 1000 ANGLE 0 120.CON I 1 LIGNE 1 OUVERT.DOM CONTOUR 1.GEN MAIL 1

" Give the orientation.BEAM TOUT DIR 0 0 1Element selection: I J K

GROUP "…"ATT –

Direction: NODE | POINT | CPOINTDIR - - - of Y(PLANZ) | PLANY – (- -)

Be careful to indefinite solutions

x

z

y

PLANZ

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Structural elements

! Physical properties: Beam definition" Define a beam profile.BPR UNITE 0.001 TYPE "U" FORMAT " H B TW TF "

NOM "PRO01" VALEUR 100 40 5 5

UNITE: Ratio between the unit length used and the meterTYPE: Several predefined profiles available

FORMAT: List of parameters (for repetitive input)

Etc.

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Structural elements

! Physical properties: Beam definition" Define a beam profileNOM: Gives a name to the profileVALEUR: Define profile dimensions

RemarkH- B- TW … Explicit dimension orAIRE- IT- IU- IV- ALPHA- YC- ZC- YM- ZM- AY- AZ-

Explicit section properties

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Structural elements

! Physical properties: Beam definition Remark (cont)" IMPORT CATALOG "…" Import profiles from files (ARBED)" Torsion inertia are approximated (ARBED,… formula's)" If non-linear material #### Integration Points" VI "PRO01" ;LIST "PRO01"

Aire/y : 375.000000000000Aire/z : 475.000000000000Iw : 187184175.459072

Caracteristiques d'un profil de poutre : ======================================

Nom : PRO01Unit : mmType : UDimensions : (H B TW TF R1 R2)100. 40. 5. 5. 0. 0.

Aire : 850.000000000000It : 7323.05054037006Iu : 1207083.33333333Iv : 119123.774509804Angle : 0.Centre G : 10.7352941176471 0.Centre M :-10.6426367794270 0.

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Structural elements

! Physical properties: Beam definition" Assign the profile to elements.AEL PROFILE "PRO01" EXCE ey ez

Gives the "element" positionIn the "profile" axes" Check.DES VP 2 | 1 VI

Equivalent inertias

GRAP ORI

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Structural elements

! Super-element: Principle

cTcrccrr

crccTcrrrrr

GKKGGKKKKK

1*

1*

−

−

−=

−=Nodes to

connect "R"

Nodes to condense "C"

Gc

Gr

Can be assembledMoved, Rotated

Can be connected to

other elementsMulti partners project

Also in dynamicNon-linear (rotation)

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Structural elements

! Super-element: 3 steps, File management

.CSUPCreation

ASEFDYNAM

Cre_xx.u18 Cre.u04,…

UseASEF

DYNAMMECANO

Uti_yy.u18.USUP

Cre.sdb

RestitASEF

DYNAM.RSUP

Uti.sdb

Res_xx.u18Res.sdb

"Optional" files

3 different names

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Structural elements

! Super-element: Generation .NOE .MAI Mesh, properties, BC, ….RET I J K

GROUP "…" (COMP -) Describe the boundary.CSU STATIQUE | DYNAMIQUE Set the "creation" variables

N - - Define a sketch to outlinePOINT - - the super-elementRET

VI

.DES RET VI

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Structural elements! Super-element: Use

.NOE .MAI Mesh, properties, BC, …

.USUP CHARGE DB "csu" Load the database

After that point boundary nodes are createdTX … RX … INIT …

CAS CHARGE k VALEUR J

CAS CHARGE 1 VALEUR "$1+$3-$2"

I – NOM "…" SAUVE Identify the super-element

VI

.DES VI

Define use load cases function of creation one

Sketch nodes

Nodes can be glued afterwards

Geometrical transformations can be applied

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Structural elements! Super-element: Back substitution

.RSUP CHARGE DB "usu" Load the databaseUSE "ASEF" … Indicate the module who used

I – NAME "…"

CAS CHARGE -TEMPS -MODE –…

! Remarks" Equilibrium of the use problem needs rigid body modes in

the super-element" The true potential energy is the sum of use problem and

internal load contributions (part of the restitution problem)

Which case to restitute

Which super element in the use problem to restitute

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Structural elements! Super-element: Import/Export

! BACON.INT NAS "…" Import NASTRAN super-element

(OP2,OP4)DMIG "…" Import NASTRAN super-element DMIGPESE "…" Import PERMAS super-element

(ARIANESPACE)

! POSTFAC.NEU Export PERMAS, ARIANESPACE,

ELFINI super-element

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Special elements

! Element library initiated by cinematic joins! Linear or non-linear constrains! Other special feature! Define explicitly by .MCE .MCC command or

implicitly by macro command (.STI .APS .RIV .RBE .MPL)

Example

.MCE I 1 BUSH N 1 2 GP 1

.MCC GP 1 BUSH KTX - KTY – KTZ -V11 1 V12 0 V13 0V21 0 V22 1 V23 0

Element type

Group id

Element properties

Element axis

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Special elements

! Non-linear constrain

.MCE I - CNLI N - - … GP –

.MCC GP 1 CNLI COMP - - …

COEF - - … (c)

COEF nf Function with $1 $2 …

DISP 1 AXL 1

To apply a right hand side:.CLM CHA ELEM I – CNLI VAL – NC - |TIME NF -

0====++++∑∑∑∑ sqiiαααα

As many terms in the constrain

By default Constrains are defined on positions in global axis !!

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Special elements! Joining of 2 meshes

" Different sizes: Fine mesh #### Coarse mesh" Different types: Shell elements #### volume elements

1. Different size: volume to volume or shell to shell" .STI GROUP Slave_node_group Master_group [PROJ]

" Slave: nodes (fine mesh) Master: faces or shell (coarse mesh)" Creates MAPP elements

ξ,ηξ,ηξ,ηξ,η

3 constrains on displacementsThe same constrains on rotationsOPT 2

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Special elements

! Joining of 2 meshes2. Different size: shell to shell.APS GROUP Slave_node_group Master_facet_group ROTATION

Slave: Nodes (fine mesh)Master: FACE group of shell (edge) (Coarse)

Generate SH3D elements

3 constrains on displacements3 constrains on rotations OPT 23dr degree function displacements

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Special elements

! Joining of 2 meshes3. Different type: Shell to volume

.APS GROUP Slave_node_group Master_facet_group

Slave: Nodes (volume)Master: FACE group of shell (edge)Generate SH3D elements

3 constrains on displacements OPT 1

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Special elements

! Joining of 2 meshes4. Different type: Shell to volume (classical solution)

Rotations of shells are not connected to volume dof'sUse dummy shells or beams to spread the stress !

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Special elements

! Rivet modeling

.RI2 GRA First_group GRB Second_groupPOINTS ... orLIGN- PITCH- | NRIV– Rivet locationKTR- KTZ- KRR- KRZ- Rivet stiffnessV1--- V2--- Rivet orientation (Default: along the line)

For each rivet: 2 MAPP elements OPT 21 BUSH element KTR- …

In the current version, in some cases (bending) efforts in rivets are overestimated

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Special elements

! Rigid body

.RBE [N -] GROUP Slave_nodes $ [OPT -] $[MAT Material_name]

Link a master node N to a group of slave nodes (N can be the 1st node of thegroup)

Generates n or (n-1) RIGI elements betweenthe master and the slave nodes

By default slave rotations are linked, to let it free: use OPT 3 (volume)For thermal effect, introduce a material MAT or an ALPHA coefficient

Master node has always 6 dof's, be careful with volume

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Special elements

! Planarity condition

.MPL [N -] GROUP Slave_nodes $ [OPT -] $DIR--- | DNOE-- | DPOI--

Impose planarity between node N and a group of slave nodes (N can be the 1st node of thegroup)

Generates n or (n-1) PLAN elements betweenthe master and the slave nodes

By default slave rotations are linked, to let it free: use OPT 1 (volume)

Master node has always 6 dof's, be careful with volume (slave and master)Useful in large rotation

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Special elements

! Surface conditions

.MDS N - GROUP Slave_nodesSURF RCYL- | RSH- | …V11- V12- … | …

Impose conditions between node N and a group of slave nodes

Generates n SURF elements betweenthe master and the slave nodes

A lot of surfaces available, even .FCT x(u,v) y(u.v) for general purpose

The slave rotations are freeMaster node has always 6 dof's, be careful with volumeUseful in large rotation

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Material properties

! Several material models are available

Non-linear material available in MECANO but also in linear modules

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Material properties

! Material definition, general syntax .MAT" .MAT I nummat NOM "name"

BEHA "Elastic" Behavior selection YT E NF nfE Young's modulus NT nu NF nfnu Poisson's ratio A al NF nfal Dilatation coefficient M M Density KIRC | BIOT | CAUC Selection of strain/Stress

measurement TREF Tref Reference temperature

If a parameter depends on the temperature, NF must be introduced on the same line !

Identification by name is useful for data structuringMaterial must be assigned to elements .AEL - MAT - | "…"

It can be visualized .DES MAT VI

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Material properties

! Material definition, othotropy or anisotropy" .MAT I nummat NOM "name"

BEHA "Elastic" Behavior selection YT Ex Ey Ez NF - - - Young's moduliG Gx Gy Gz NF - - - Shear moduliNT nx ny nz NF - - - Poisson's ratio A ax ay az NF - - - Thermal expansion coefficient

" .MAT YT h11 h21 h22 … $ 21 terms of the Hooke matrixNF … εεεεx εεεεy εεεεz γγγγxy γγγγyz γγγγxz

Properties in element axisIf a parameter depends on the temperature, NF must be introduced

on the same line !As many functions as coefficients

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Boundary conditions

! Nodal conditions.CLM CHA NOE 1 VAL 1 2 3 NC 1

Case idNOM "…"

TIME - | TIME NF -

Values: vector orCOMP – VAL -

SupportGROUP "…"

Type of BC: FIX

DEP prescribe displacement

• may be different by load case

• if function of time, may be defined/undefined

• For large rotations: HING

FOL Following force

• Non-symmetric stiffness

• Moments: always Non-sym

FOLCHA Only one definition

• To cumulate: ADDITION

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Boundary conditions

! Frame: General frame definition" For nodal boundary conditions" For element properties.FRAM I – TYPE – ORIGIN – V1 – V2 – V3 -

Type of frameCARTESIANCYLINDRICALSPHERICAL

Origin of framex y zNODE -POINT -

Axis orientationV1 x y zV1 NODE - From origin toV1 POINT –

Local Cartesianframe function of

the relative position to the

origin !!

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Boundary conditions

! Local axis on node.AXL I – AXE – DIRECTION

.AXL I – FRAME –

(No visualization!)

.AXL LIGNE 5

AXE 1 TANGENT

AXE 2 NORMAL

.DES AXL 1|2 VI

Nodes to treatI- J- K-GROUP "…"LIGNE -

Axis orientationx y zNODE - - (-)POINT - - (-)

• In non-linear analysis, local axis do not rotate with the structure

• Local axis should be perpendicular !?!

• In 2d only one axis is needed, in 3d 2 axes. The last is perpendicular.

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Boundary conditions

! Surface loads" 3d: Applied on volume face and shell" 2d: Applied on edge.CLM PRE FACE - - VAL –

Average value or 1 value by vertices

SupportMAIL –GROUP "…"

Type of load

PRE pressureSFxyz surface loadZLIQ ROG Hydrostatic press.

Pressure acts toward

the volumethe normal to the shell

Updated with structure deformation

Surface loads

Along a structural axis

Constant with structure deformation

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Boundary conditions

! Line loads

.CLM PRX MAIL - VAL –

Type of load

PRX PRY Linear PressureSFxyz line load

Pressure

In the beam axes

Updated with structure deformation

Line loads

Along a structural axis

Constant with structure deformation

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Boundary conditions

! Body loads" Inertia forces" Need a mass" Applied on the whole structure or on an element selectionACC VAL - - - Acceleration in structural axes (m/s2)ROT VAL - - - (CROT - - -)

Rotation in structural axes (rad/s)DROT VAL - - - Rotary acceleration (rad/s2)

Remark: Units" International system

m kg s (ρρρρ = kg/m3 E = N/m2)" Common system

mm T s (ρρρρ = kg/mm3 m/mm (T/mm3) E = N/mm2)

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Boundary conditions! Check loads

.CLM VI PRE FACE TIME -

The type of load must be defined

The type of support must be defined

For time dependent values

The instant must be definedIf 1 item is selected, y=f(t)

VECT

VECT 0Useful to checkthe orientation of shell elements

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Boundary conditions! Thermal loads and temperature definition

Thermal loads must induce thermal strains (Duhamel's problem)If thermal strains are equal to α ∆α ∆α ∆α ∆T, if H is the Hooke matrixσσσσtherm = H α ∆α ∆α ∆α ∆T at 0 mechanical strain. Thermal loads are ∫∫∫∫ σσσσtherm

α α α α Thermal coefficient, defined by materialmay be orthotropicmay depend on temperature

∆∆∆∆T Temperature step between current and reference temp.Current temp: .CLT TFXReference temp: .GEL TEMP or .MAT TREF

Remark: a more general expression of thermal strain isΕΕΕΕtherm = αααα(T)(T-Tref) + αααα(T0)(T0-Tref) (T0= temperature at time 0)

In a linear analysis, thermal loads are introduced for the first load caseTo apply them on an other load case, use .CAS CODE 77 N loadcase#

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Boundary conditions! Thermal loads and temperature definition

.CLT TFX NODE I - VAL – (TIME - |TIME NF -)

TFX: Imposed temperatureTIN: Initial temperatureDTF: Temperature step through the thickness for shell

elements(>0 upper skin warmer than lower)Temperature can be imported from MECANO Thermal.SAM IUN 39 (name_mt.u18).GEL TIME - Choose a time for a linear analysis

Interpolation for a transient analysisMeshes can be either identical or quasi identicalFor non-identical meshes interpolation can be done with

.ITM .IT3

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Boundary conditions! Load or properties mapping

One can map continuous field like:" Pressure (.CLM)" Temperature (.CLT)" Physical properties (.PHP)ONE, TWO or FOUR functions must be defined on nodes or pointsValues are interpolated and extrapolated

B-spline Ruled surface Coons surface

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Boundary conditions! Load or properties mapping1. Define functions

.FCT CREE FONCTION I - NOM "..."

CREE VALEURS Y U

NOEUDS- - ... OrPOINTS- - ...

ORDONNEES- - ...

2. Map the field.CLM GROUP "…" MAP - NC - | TIME - | TIME NF –

MAP - - or MAP - - - -

Values can be cumulated ADDITION

There is a special syntax if values do not vary equally function of the time:MA1 - - … MA2 - - … MAx …

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Boundary conditions! Load or properties mapping: Example.FCT CREE FONCTION I 11

CREE VALEUR Y U

POINT 1 2

ORDON 1 1

.CLM PRESS GROUPE "pres1" MAP 22 23 NC 1

PRESS GROUPE "pres1" MAP 11 12 NC 2

VI PRESS NC 1

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Boundary conditions! Pressure adjustment

" Due to mesh approximation a global resultant may be not accurate

" If the pressure distribution is unknownA least square method can be used to calculate pressures

equivalent to a given resultant

.ADJ GROUPE "pres1"

FX (-/DX*/DY*PI) FY 0 FZ 0 MX 0 MY 0 MZ 0 NC 1 CALC

The support is selected for several adjustment

Prescribed resultant

It is not equal to introduce FY 0 or not

The more the problem is constrained the higher the adjustment

Must be equivalent to the CLM definition

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Boundary conditions! Pressure adjustment: Example.ADJ CALC LIST –1 Gives a summery of the adjustment

αααα = scaling factorS = adjustment quality

To visualize the correction.CLM VI ADP ELEM NC 1

∫∫=ss

pps 22 )(/ˆ α

ppp inittot ˆ++++====αααα

Total pressure

Adjustment

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Boundary conditions! Contact conditions

Tree kinds of contact may be defined1. Rigid surface / flexible structure .MDS

Relative distance between nodes and the surface, updated in non-linear

2. Flexible / flexible structure, small displacements .CPSThe relations between relative displacements are written on the un-deformed shape

3. Flexible / flexible structure, large displacements .MCTThe relations between relative displacements are continuously updated.The matrix profile can be updated (large contact surfaces)

Remark: It is possible to define friction in all cases

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In MECANO, two algorithms are possible1. Coupled iterations: Contact is treated with other non-linear

elements. Condition is defined with Lagrange multipliers technique. (MCT, MDS)

2. Uncoupled iterations: At each Newton iteration, Dof's not involved in the contact problem as condensed like for a super-element. The contact problem is solved iteratively until local convergence. (MCT, MDS, CPS)

In ASEF, internal dof's are condensed once. (MCT, MDS, CPS)

In ASEF and MECANO with uncoupled iteration a special algorithm is used to solve contact with friction problem (Variable penaltymethod .ALGO)

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Rigid surface / flexible structure .MDS

Rigid surface can be:• a CAD surface (ruled,…)• a function (2D/3D) defined by .FCT command• predefined (cylinder, sphere, …)

Master Node

Slave Node

Rigid surface

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Boundary conditions! Rigid surface / flexible structure .MDS

Surface is defined independently of structural coordinates!!Surface divides space into two sub-spaces.Positive distances (Traction) are pointed by curvilinear w-axis." 2D axi-symmetric or extruded surface

YFCT θθθθFCT

u

vw

XFCT

.FCT CREE FONC NOM "F1"CREE VALEUR X U

ANALYTIC "$U"CREE VALEUR Y U

ANALYTIC "0."

YFCT ΘΘΘΘFCT

uvw

XFCT

.FCT CREE FONC NOM "F2"CREE VALEUR X U

ANALYTIC "$U"CREE VALEUR Y U

ANALYTIC "$U*$U"

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Boundary conditions! Rigid surface / flexible structure .MDS

3D surface

" Predefined surface• Infinite cylinder and cone

• Sphere (w points inside)

" User routine

.FCT CREE FONCTION NOM "Plane"CREE VALEUR X U BORNES 0 5 V 0 1

ANALYTIC "$U"CREE VALEUR Y U BORNES 0 5 V 0 1

ANALYTIC "$V"CREE VALEUR Z U

ANALYTIC "0."

ZFCT

uv

w

XFCT

YFCT

XFCTYFCT

wZFCT

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Boundary conditions! Rigid surface / flexible structure .MDS (syntax).MDS N master-Node GROUP Slave-Node-group

SURF OPTION 2 | 3 coupled or uncoupled iterationsNF2D nf2 | NF3D nf3 | RCYL r …

V11 - V12 … | FRAME | …

LC max-compression or LT max-traction

CF friction-coefficient

OPTION 2 coupled iterations (MECANO)OPTION 3 uncoupled iterations (ASEF and MECANO)Origin of (XFCT,YFCT,ZFCT) coordinate system is on master node (6dof's).Orientation is defined by V11, V12, … or other parameters. Positive distances pointed by w vector are forbidden using LT parameter

(LC to forbid negative distances).The kind of surface (2D/3D/predefined) is independent of the kind of

analysis. In particular, a 2D axi-symmetric function may be used in 3D.

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Boundary conditions! Flexible / flexible structure, small displacements .CPS

" “Linear” contact conditions available in MECANO and ASEF

" The distance between the node and the facet is computed by preprocessor. For this reason, only small displacements are acceptable.

" Contact problem is solved at each Newton’s iteration (uncoupled iteration) either by a mathematical programming algorithm or by a variable penalty approach.

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Boundary conditions! Flexible / flexible structure, small displacements .CPS

" This command may only be used with the frontal or multifrontalsolvers:.SUB RESO 3/5

" Without friction a mathematical programming algorithm is used. Contact is defined between a group of nodes (n1) and a group of master faces (f2)..CPS GROUP n1 f2

" With friction a variable penalty method is used. This algorithm is managed by .ALG command. The friction coefficient is defined by FRICTION parameter. .CPS GROUP n1 f2 FRICTION mu

.ALG PRECPENA 1E-6

PRECNEWT 1E-8

IOPC 5

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Boundary conditions! Flexible / flexible structure, large displacements .MCT

" The distance between the node and the facet is computed in MECANO

" Contact (with optional friction) is solved by Lagrange multipliers (coupled iterations) or either by a mathematical programming algorithm or by a variable penalty approach (uncoupled iterations).

" Stiffness matrix profile may be updated (.SUB IPRO 1) with skyline (RESO 1) and sparse (RESO 5) solvers.

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Boundary conditions! Flexible / flexible structure, large displacements .MCT

.MCT GROUP Node-group GTAR Facet-groupNLIM number-of-facetRMAX maximal-distanceCF friction-coefficientKSMO 1 OPTION 2 | 3

The parameter NLIM and RMAX allows to limit the number of facets to be taken into account for each node.

For positive values of NLIM, facets are selected in the preprocessorFor negative values, the facet selection is updated in MECANO (.SUB

IPRO 1).During analysis, it is possible to exclude

some facets by .SUB DCON distance(useless with reprofiling)

For rough faces mesh, KSMO allows to smooth the surface

FA

FB

DCON

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Boundary conditions! Contact conditions: Remark

" Be careful when using a finite rigid surface. Slave nodes can't "see” the surface.

" To solve convergence problems with uncoupled iteration with friction:• .ALG IOPC 5 to have a listing of variable penalty contact

algorithm• .ALG PRECNEWT -, PRECPENA -, SINIT –

" Contact with friction (coupled) is unsymmetrical problem. .SUB INLY 1 activates the non symmetric solver.

OK

KO

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Boundary conditions! Contact conditions: Remark

" .SUB RELC - PRCC - are relaxation parameters for contact dof. At a given structural iteration, the Newton’s update of contact degrees of freedom is multiplied by RELC. This relaxation is performed as long as convergence criterion (TESF) is greater than PRCC (coupled).

" .SUB RUP - RDOWN - are the increasing (decreasing) rate of time step. It is useful to chose mod(RUP/RDOWN) ≠≠≠≠ 0 not to reanalyze a failed time step

" .SUB PRCS - is the regularization (penalty) coefficient. It does not influence the solution but it changes the way to find the solution.

" Contact pressure, gap distance and sliding distance can vi visualized in post-processing ( CODE 1305 1306 1307 and 2051 )

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Post-processing

! General view" After an analysis, FAC program (automatically) sorts results

for post-processing. A dedicated pair of files is generatedProblem_name_xx.des Problem_name_xx.fac

xx Identify the analysis module as=ASEF me=MECANO etc." For post-processing use BACON but through bp identifier

samcef (–as,)bp problem_name n 1

" Results are identified by a CODE (type of results) and a REF (result occurrence: load case, time step, vibration mode …)

" Main commands are:• .DES Visualization of results on the mesh

Deformed shape, element contour, tensor cross, …• .VIF Visualization of results function of abscissa

Result function of time, other functions (section)

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Post-processing

! Access to results" .DOC DB (FORMAT) Reload the default problem database" problem_name_xx.des problem_name_xx.fac

Assign by default to unit 20 21" To access other results

ASSIGN FAC "other_name_xx" UNIT 22

" To compare results, assign several files (increase UNIT by 2)

Advanced tipIn samcef.proc file, unit 20 and 21 are assigned to

&NOM._&LCP..DES and &NOM._&LCP..FACOne can add in userproc file

ASSIGN UNIT 20,FILE=&NOM.&NOM2._&LCP..DES

NOM2 can be a first name (in the environment SAM_NOM2)

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Post-processing

! Different type of results" By nodes

• Scalar: temperature• Vector: displacement

speed" By elements

• Scalar: mean Von Mises• Vector: thermal flux• Tensor: mean stress

mean strains" By node/By element

• Scalar: extrapolated Von Mises• Tensor: extrapolated stress

extrapolated strain

COMPVONMISE

COMPVONMISE

COMP

MOY

ISO

DISC 0

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Post-processing

! Convention for code numbering" Nodal results (119< <271)

163 Displacements221 Reactions9xxx Selected results for time evolution (.VIF)

" Element results1xxx Results by node by element3xxx Mean results by element9xxx Selected results for time evolution (.VIF)y3xx Scalar valuesy4xx Tensorial valuesy5xx Vectorial valuesExample 1411 3d stress tensor (volume)

1431 2d stress tensor (shell)

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Post-processing

! Convention for reference numbering" To load a result:.DES CODE xxx REF r n

r: reference4 Load case 8 Time step6 Vibration mode 9 Rigid body mode7 Buckling mode

" For transient analysis.DES CODE xxx RTIME time.

Remark" A reference remains active until it is modified" If reference changes all results in memory are reset" To see the results available LIST DESC (2) (CODE -)" REF without parameters presents a list of available refs

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Post-processing! Results selection (.SAI)

" Mostly used code are archived by default" To select other results" To select time dependent results (code 9xxx)

.SAI ARCHIVE | IMPRESS

element_selection | node_selection | SRUCTURE

(COMPONENT - - …) STYPE code …

Remark" Be careful with file size" To unselect results: STYPE < 0" For some results: can be executed afterward

1. .DOC DB

2. .SAI …

3. .SAUVE DB

4. samcef (-as),fa

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Post-processing! Selection for visualization

" Selections are cumulative" One can select:

ELEMENT i j k TRIANGLE POUTRE BARREATTRIBUTE – VOLUME RESSORT …GROUPE - | "…" NODE i j k

" To reset the selection MAI and/or ATTRIB" To unselect SUPPRIME selection" Other selection tools:

GRAP COUPE XI – YI – XS – YS – ZI – ZS –

• In structural axis !• If GRAP INIT, one can use GRAP COUPE XI /

" If MCE MCC elements:.MCC SUPP SEL GP –

" To adapt the scale ADAPT VMIN VMAX

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Post-processing

! Common post-processing: Example.DEL.*

.POI I 1 X 0

X 100

X 100 Y 10

X 0 Y 10

.DRO POINT 1 2 3 4 1

.CON AUTO

.DOM AUTO

.GEN MODIFIE LIGNE 2 4 ELEM 3 $DISTRI 10 0. .2 .8 1.

MAIL 1

.HYP MEMBRANE BIDIM

.MAT NOM "Acier"

YT 210000 NT 0.3

.SEL GROUPE MAIL NOM "Beam"

ATT 1

GROUPE FACE NOM "F_Fixa"

ORI -1 0 0

GROUPE NOE NOM "Fixa"

TRANSFORME "F_Fixa"

GROUPE FACE NOM "Press"

ORI 0 1 0

.AEL GROUPE "Beam" MAT "Acier"

.PHP GROUPE "Beam" THICK VAL 1

.CLM FIXA GROUP "Fixa"

PRESS GROUP "Press" VAL 100

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Post-processing! Common post-processing: Deformed shape

CODE 163 DEFO VI

DEFO scale

=1 for non-linearCareful with contactLIST 1 10 1

MOD DEPL VI

LIST 10 TRI (-1)

GRAP EFF 0 REMP 0 CM 1 GL 1

DEFO 0 ISO 0 VI

GRAP EFF REMP CM 6 GL 0 !!

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Post-processing! Common post-processing: Deformed shape

" AnimationANIM LIN 1 Linear cartoon effect between 0 and DEFOANIM LIN 0 Sinusoidal between -DEFO and DEFOANIM LIN 2 Non-linear animation over several time steps

Start ####End ####Start ####End …ANIM LIN 3 Start ####End Start ####End …Runs over REPETE loops or stopped by ^c in the shell

windowsCan be time consuming, GRAP ARET 2 can help

" Vector of displacementsVECT DEPL VI

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Post-processing! Common post-processing: Stress

" Several combinations

+ ISO 0 | 1+ DISC 0 | 1

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" ISO To transform element average values in nodal value

" DISC To smooth extrapolated element values

ISO 1

ISO 0

DISC 0

DISC 1

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" ECART Gives an estimation of the approximation

ECART 1100(vmax - vmin)/

(VMAX - VMIN)

ECART 3Largest Vmax Vmin

Not valid between 2 materials

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Post-processing! Common post-processing: Sections

" If iso-lines are available for visualization" If a 3d mesh is used

• The mesh can be cut by a plane perpendicular to the screen and supported by 2 points

" If a 2d mesh is used• A function is drawn with the values at the cross section

of the plane and the mesh

SECTION P1 /SECTION PN1 – PN2 –VI FCT – For further use

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Post-processing! Common post-processing: Sections

" If iso-lines are available for visualization" One can distribute a series of points along line(s) and plot

the evolution along the abscissa

L1L2

L3L4

SECTION LIGNE 1 2 3 4

LSECTION …

SECTIONNearest nodes(from cad)LSECTION …Projection on shell or interpolation in the volume for n points

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Post-processing! Common post-processing

" Result manipulationDEPL COMP 1 MEMO 1

DEPL COMP 2 MEMO 2

OPERATION "$1*COS(30)+$2*SIN(30)"

" Result scaling and additionCODE – REF - - FACTEUR –

CODE – REF - - ADDITION

" To compare two results nearly identicalCODE – REF - - UNITE 20

CODE – REF - - UNITE 22 ADDITION FACTEUR –1

" Other useful parametersGRAP LEGENDE CADRE GRADUATION

.DES AFFICHE V1D 1 | 0 VMIN VMAX

Operation on scalar by node or scalar by node by element

Results combination

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Post-processing! Load resultant

" To calculate the resultant force (reaction)

" Be careful with phantom nodes (middle of contact faces)" For post-processing

.SAI ARCH ELEM – STYPE 1524 1525 (Force Moment)" To select a group of internal faces .SEL PEAU 0

From a group of fixations

Acting through a predefined section

.MNT I – NEUDM – GROUP group_of_nodes | group_of_faces(AXE1 - - - AXE2 - - -)

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Post-processing! Export curves to Excel

" Several results can be transformed in a function• Transient analysis

.VIF CHA CODE – ELEMENT – FCT –

• 1d section between 2 planes (screen and normal plan)Along a CAD line.DES CHA CODE – REF - -

VI FCT –

" To export such function to text Excel file.EXP EXCEL "name" FONCTION - A - PAS – (COMP)

Remark" File extension is .txt" Decimal symbol is point "." field separator is semicolon ";"" Be careful with "Regional Settings"

To merge function with identical abscissa

Documents

Advanced Modeling in SAMCEFoss.jishulink.com/caenet/forums/upload/2014/12/16/396/...2005/08/11 · Contact problems (Type of contact, Algorithm description, data files, guide lines)