! FEA computer laboratory NL6: POST BUCKLING OF A PLATE WITH CENTRAL HOLE

Initial setup

! White canvas
/RGB/RGB, Kywrd, PRED, PGRN, PBLU, N1, N2, NINC, NCNTR Specifies the RGB color values for indices and contours.,INDEX,100,100,100,0
/RGB/RGB, Kywrd, PRED, PGRN, PBLU, N1, N2, NINC, NCNTR Specifies the RGB color values for indices and contours.,INDEX,0,0,0,15
/ESHAPE/ESHAPE, SCALE, KEY Displays elements with shapes determined from the real constants or section definition.,1.0
! [N], [Nm], [N/m^2=Pa], [N/m]
!
! Define constant parameters
A=0.25
R=0.04
t1=0.25E-3
t=3E-3
!
F=180E3
!
Exx=127.6E9
Eyy=11.03E9
Ezz=11.03E9
nuxy=0.27
nuyz=0.03
nuxz=0.03
Gxy=5.74E9
Gyz=5.74E9
Gxz=5.74E9
!
PI=4*ATAN(1)

SETUP: element types, materials, layup

/PREP7/PREP7 Enters the model creation preprocessor.

!
ETET, ITYPE, Ename, KOP1, KOP2, KOP3, KOP4, KOP5, KOP6, INOPR Defines a local element type from the element library.,1,SHELL181
KEYOPTKEYOPT, ITYPE, KNUM, VALUE Sets element key options.,1,8,1
!
ESYSESYS, KCN Sets the element coordinate system attribute pointer.,0
!
MPTEMPMPTEMP, SLOC, T1, T2, T3, T4, T5, T6 Defines a temperature table for material properties.,1,0
MPDATAMPDATA, Lab, MAT, SLOC, C1, C2, C3, C4, C5, C6 Defines property data to be associated with the temperature table.,EX,1,,ExxExx = 127.6E9
MPDATAMPDATA, Lab, MAT, SLOC, C1, C2, C3, C4, C5, C6 Defines property data to be associated with the temperature table.,EY,1,,EyyEyy = 11.03E9
MPDATAMPDATA, Lab, MAT, SLOC, C1, C2, C3, C4, C5, C6 Defines property data to be associated with the temperature table.,EZ,1,,EzzEzz = 11.03E9
MPDATAMPDATA, Lab, MAT, SLOC, C1, C2, C3, C4, C5, C6 Defines property data to be associated with the temperature table.,NUXY,1,,nuxynuxy = 0.27
MPDATAMPDATA, Lab, MAT, SLOC, C1, C2, C3, C4, C5, C6 Defines property data to be associated with the temperature table.,NUYZ,1,,nuyznuyz = 0.03
MPDATAMPDATA, Lab, MAT, SLOC, C1, C2, C3, C4, C5, C6 Defines property data to be associated with the temperature table.,NUXZ,1,,nuxznuxz = 0.03
MPDATAMPDATA, Lab, MAT, SLOC, C1, C2, C3, C4, C5, C6 Defines property data to be associated with the temperature table.,GXY,1,,GxyGxy = 5.74E9
MPDATAMPDATA, Lab, MAT, SLOC, C1, C2, C3, C4, C5, C6 Defines property data to be associated with the temperature table.,GYZ,1,,GyzGyz = 5.74E9
MPDATAMPDATA, Lab, MAT, SLOC, C1, C2, C3, C4, C5, C6 Defines property data to be associated with the temperature table.,GXZ,1,,GxzGxz = 5.74E9
!
! Define shell layup
SECTYPESECTYPE, SECID, Type, Subtype, Name, REFINEKEY Associates section type information with a section ID number.,1,SHELL
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,30,3
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,-30,3
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,30,3
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,-30,3
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,30,3
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,-30,3
!
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,-30,3
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,30,3
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,-30,3
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,30,3
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,-30,3
SECDATASECDATA, VAL1, VAL2, VAL3, VAL4, VAL5, VAL6, VAL7, VAL8, VAL9, VAL10, VAL11, VAL12 Describes the geometry of a section.,t1t1 = 0.25E-3,1,30,3
SECOFFSETSECOFFSET, Location, OFFSET1, OFFSET2, CG-Y, CG-Z, SH-Y, SH-Z Defines the section offset for cross sections.,MID
!*
SECPLOTSECPLOT, SECID, VAL1, VAL2, VAL3 Plots the geometry of a beam, pipe, shell, or reinforcing section to scale.,1!Click here to view image

Modeling

KK, NPT, X, Y, Z Defines a keypoint.,1,0,0
KK, NPT, X, Y, Z Defines a keypoint.,2,AA = 0.25,0
KK, NPT, X, Y, Z Defines a keypoint.,3,AA = 0.25,AA = 0.25
KK, NPT, X, Y, Z Defines a keypoint.,4,0,AA = 0.25

!
AA, P1, P2, P3, P4, P5, P6, P7, P8, P9, P10, P11, P12, P13, P14, P15, P16, P17, P18 Defines an area by connecting keypoints.,1,2,3,4
CYL4CYL4, XCENTER, YCENTER, RAD1, THETA1, RAD2, THETA2, DEPTH Creates a circular area or cylindrical volume anywhere on the working plane.,AA = 0.25/2,AA = 0.25/2,RR = 0.04
ASBAASBA, NA1, NA2, SEPO, KEEP1, KEEP2 Subtracts areas from areas.,1,2
!
NUMCMPNUMCMP, Label Compresses the numbering of defined items.,ALL

Meshing

*DO*DO, Par, IVAL, FVAL, INC Defines the beginning of a do-loop.,III,1,4
  LESIZELESIZE, NL1, SIZE, ANGSIZ, NDIV, SPACE, KFORC, LAYER1, LAYER2, KYNDIV Specifies the divisions and spacing ratio on unmeshed lines.,III,,,20
*ENDDO*ENDDO Ends a do-loop and starts the looping action.

!
*DO*DO, Par, IVAL, FVAL, INC Defines the beginning of a do-loop.,III,5,8
  LESIZELESIZE, NL1, SIZE, ANGSIZ, NDIV, SPACE, KFORC, LAYER1, LAYER2, KYNDIV Specifies the divisions and spacing ratio on unmeshed lines.,III,,,10
*ENDDO*ENDDO Ends a do-loop and starts the looping action.
!
AMESHAMESH, NA1, NA2, NINC Generates nodes and area elements within areas.,1!Click here to view image
!
! detach mesh
MODMSHMODMSH, Lab Controls the relationship of the solid model and the FE model.,DETACH
! Move nodes to 'help' the formation of buckling
*GET*GET, Par, Entity, ENTNUM, Item1, IT1NUM, Item2, IT2NUM Retrieves a value and stores it as a scalar parameter or part of an array parameter.,NNUMBER,NODE,0,NUM,MAX
!
*DO*DO, Par, IVAL, FVAL, INC Defines the beginning of a do-loop.,I,1,NNUMBER
TMPZ = SIN(PI*NX(I)/A)*SIN(PI*NY(I)/A)*(3E-5)
  NN, NODE, X, Y, Z, THXY, THYZ, THZX Defines a node.,I,NX(I),NY(I),TMPZ
*ENDDO*ENDDO Ends a do-loop and starts the looping action.
FINISHFINISH Exits normally from a processor.

Solution

/SOLU/SOLU Enters the solution processor.

! Setting up the solution
ANTYPEANTYPE, Antype, Status, LDSTEP, SUBSTEP, Action Specifies the analysis type and restart status.,0
NLGEOMNLGEOM, Key Includes large-deflection effects in a static or full transient analysis.,1
NSUBSTNSUBST, NSBSTP, NSBMX, NSBMN, Carry Specifies the number of substeps to be taken this load step.,300,1000,100
OUTRESOUTRES, Item, Freq, Cname, -- , NSVAR, DSUBres Controls the solution data written to the database.,ALL,ALL
! Setting the kinematic constraints on lines
NSELNSEL, Type, Item, Comp, VMIN, VMAX, VINC, KABS Selects a subset of nodes.,S,LOC,X,0
DD, Node, Lab, VALUE, VALUE2, NEND, NINC, Lab2, Lab3, Lab4, Lab5, Lab6 Defines degree-of-freedom constraints at nodes.,ALL,ALL,0
!
NSELNSEL, Type, Item, Comp, VMIN, VMAX, VINC, KABS Selects a subset of nodes.,S,LOC,Y,0
NSELNSEL, Type, Item, Comp, VMIN, VMAX, VINC, KABS Selects a subset of nodes.,AA = 0.25,LOC,Y,AA = 0.25
DD, Node, Lab, VALUE, VALUE2, NEND, NINC, Lab2, Lab3, Lab4, Lab5, Lab6 Defines degree-of-freedom constraints at nodes.,ALL,UZ,0
DD, Node, Lab, VALUE, VALUE2, NEND, NINC, Lab2, Lab3, Lab4, Lab5, Lab6 Defines degree-of-freedom constraints at nodes.,ALL,ROTY,0
!
NSELNSEL, Type, Item, Comp, VMIN, VMAX, VINC, KABS Selects a subset of nodes.,S,LOC,X,AA = 0.25
DD, Node, Lab, VALUE, VALUE2, NEND, NINC, Lab2, Lab3, Lab4, Lab5, Lab6 Defines degree-of-freedom constraints at nodes.,ALL,UZ,0
DD, Node, Lab, VALUE, VALUE2, NEND, NINC, Lab2, Lab3, Lab4, Lab5, Lab6 Defines degree-of-freedom constraints at nodes.,ALL,ROTX,0
DD, Node, Lab, VALUE, VALUE2, NEND, NINC, Lab2, Lab3, Lab4, Lab5, Lab6 Defines degree-of-freedom constraints at nodes.,ALL,ROTY,0
!
ALLSELALLSEL, LabT, Entity Selects all entities with a single command.,ALL
DD, Node, Lab, VALUE, VALUE2, NEND, NINC, Lab2, Lab3, Lab4, Lab5, Lab6 Defines degree-of-freedom constraints at nodes.,ALL,ROTZ,0
!
! Setting the loading on
FF, NODE, Lab, VALUE, VALUE2, NEND, NINC Specifies force loads at nodes.,NODE(A,AA = 0.25/2,0),FX,-FF = 180E3
FINISHFINISH Exits normally from a processor.
!
! Coupling the x displacements
/PREP7/PREP7 Enters the model creation preprocessor.
NSELNSEL, Type, Item, Comp, VMIN, VMAX, VINC, KABS Selects a subset of nodes.,S,LOC,X,AA = 0.25
CPCP, NSET, Lab, NODE1, NODE2, NODE3, NODE4, NODE5, NODE6, NODE7, NODE8, NODE9, NODE10, NODE11, NODE12, NODE13, NODE14, NODE15, NODE16, NODE17 Defines (or modifies) a set of coupled degrees of freedom.,1,UX,ALL
ALLSELALLSEL, LabT, Entity Selects all entities with a single command.,ALL!Click here to view image
FINISHFINISH Exits normally from a processor.
/SOL/SOLU Enters the solution processor.
SOLVESOLVE, Action Starts a solution.
FINISHFINISH Exits normally from a processor.
! Time history postprocessing
/POST26/POST26 Enters the time-history results postprocessor.
NSOLNSOL, NVAR, NODE, Item, Comp, Name, SECTOR Specifies nodal data to be stored from the results file.,2,NODE(A/2,AA = 0.25/2+R,0),U,Z,UZ_A
NSOLNSOL, NVAR, NODE, Item, Comp, Name, SECTOR Specifies nodal data to be stored from the results file.,3,NODE(A/2+R,AA = 0.25/2,0),U,Z,UZ_B
NSOLNSOL, NVAR, NODE, Item, Comp, Name, SECTOR Specifies nodal data to be stored from the results file.,4,NODE(A,AA = 0.25/2,0),U,X,UX_C
/AXLAB/AXLAB, Axis, Lab Labels the X and Y axes on graph displays.,X,'Time [s]'
/AXLAB/AXLAB, Axis, Lab Labels the X and Y axes on graph displays.,Y,'Displacement [m]'
XVARXVAR, N Specifies the X variable to be displayed.,1
PLVARPLVAR, NVAR1, NVAR2, NVAR3, NVAR4, NVAR5, NVAR6, NVAR7, NVAR8, NVAR9, NVAR10 Displays up to ten variables in the form of a graph.,2,3,4!Click here to view image
FINISHFINISH Exits normally from a processor.
! Display the displaced structure at the last timestep
/POST1/POST1 Enters the database results postprocessor.
SETSET, Lstep, Sbstep, Fact, KIMG, TIME, ANGLE, NSET, ORDER Defines the data set to be read from the results file.,LAST
/VIEW/VIEW, WN, XV, YV, ZV Defines the viewing direction for the display.,1,1,1,1
/DSCALE/DSCALE, WN, DMULT Sets the displacement multiplier for displacement displays.,ALL,4
PLNSOLPLNSOL, Item, Comp, KUND, Fact, FileID Displays results as continuous contours.,U,Z,0,1.0!Click here to view image
!Click here to view animation
! Load the macro for saving the displacement values at a given load magnitude
/INPUT/INPUT, Fname, Ext, Dir, LINE, LOG Switches the input file for the commands that follow.,LOAD_DISP,txt!LOAD DISP MACRO
!Z displacement of point A
!Z displacement of point B
!X displacement of point C
!Load value as a function of displacement
!MATLAB file for plotting the data in files