You can perform the example spectrum analysis using the Mechanical APDL commands shown below instead of GUI choices. Items prefaced by an exclamation point (!) are comments.
/prep7
/title seismic response of a beam structure
et,1,beam188
keyopt,1,3,3
sectype,1,beam,rect
secdata,71.6,3.82
mp,ex,1,30e6
mp,prxy,1,0.30
mp,dens,1,73e-5
k,1
k,2,240
k,3,0,1,0 ! define orientation keypoint
l,1,2
esize,,8
latt,,,,,,3 ! use orientation keypoint
lmesh,1
nsel,s,loc,x,0
dsym,symm,z
d,all,uy
nsel,s,loc,x,240
d,all,ux,,,,,uy
nsel,all
finish
/solu
antype,modal ! mode-frequency analysis
modopt,lanb,3 ! block lanczos, extract first 3 modes
mxpand,1,,,yes ! expand first mode shape, calculate element stresses
outpr,basic,1
solve
finish
/solu
antype,spectr ! spectrum analysis
spopt,sprs ! single point spectrum
sed,,1 ! global y-axis as spectrum direction
svtyp,3 ! seismic displacement spectrum
freq,.1,10 ! frequency points for sv vs. freq. table
sv,,.44,.44 ! spectrum values associated with frequency points
srss,0.15,disp ! square root of sum of squares mode combination
! with signif=0.15 and displacement solution requested
solve
finish
/post1
set,list
/inp,,mcom
prnsol,dof ! print nodal solution
prrsol,f ! print reaction solution
finish
/prep7 et,1,pipe288,,,3 ! PIPE288 using cubic shape function et,2,mass21 ! MASS21 ! *** Section and Real Constants sectype,1,pipe secdata,2.37500000,0.15400000,14 r,2,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,3,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,4,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,5,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,6,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,7,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,8,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,9,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,10,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,11,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,12,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,13,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,14,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,15,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 ! *** Nodes n,1,0.0,-30.00 n,2,27.25,-30.00 n,3,27.25,-30.00,17.250 n,4,0.0,-30.00,17.250 n,5,0.0,18.625,17.250 n,6,0.0,18.625,8.625 n,7,0.0,18.625 n,8,8.625,18.625, n,9,18.625,18.625 n,10,27.25,18.625 n,11,27.25,18.625,8.625 n,12,27.25,18.625,17.250 n,13,18.625,18.625,17.250 n,14,8.625,18.625,17.250 n,15,0.0,-80.00 n,16,27.25,-80.00 n,17,27.25,-80.00,17.250 n,18,0.0,-80.00,17.25 ! *** Mesh of Straight Pipe: Tangent Elements mat,1 type,1 secnum,1 en,1,15,1 en,2,1,7 en,3,7,6 en,4,6,5 en,5,5,4 en,6,4,18 en,7,16,2 en,8,2,10 en,9,10,11 en,10,11,12 en,11,12,3 en,12,3,17 en,13,12,13 en,14,13,14 en,15,14,5 en,16,7,8 en,17,8,9 en,18,9,10 ! *** Mass Elements mat,1 type,2 real,2 en,19,1 real,3 en,20,2 real,4 en,21,3 real,5 en,22,4 real,6 en,23,5 real,7 en,24,6 real,8 en,25,7 real,9 en,26,8 real,10 en,27,9 real,11 en,28,10 real,12 en,29,11 real,13 en,30,12 real,14 en,31,13 real,15 en,32,14 ! *** Component for Support Nodes nsel,s,node,,15 nsel,a,node,,16 nsel,a,node,,17 nsel,a,node,,18 cm,fixedsu,node allsel,all ! *** Material mp,ex,1,27899996.8 mp,nuxy,1,0.3 mp,dens,1,2.587991718e-10 ! *** Constraints d,15,all,0 d,16,all,0 d,17,all,0 d,18,all,0 allsel,all finish ! *** Modal Analysis ! ****************** /solution antype,modal modopt,lanb,5 mxpand,,,,yes ! request the element results solve save ! save the database finish !** Spectrum Analysis !********************* /solution antype,spectr spopt,sprs,,, dmprat,0.02 grp,0.001 svtyp,2 sed,1 ! X-direction base excitation freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2 freq,35,40,588 sv,0.02,400,871,871,700,1188,1188,440,775,775 sv,0.02,380,348.6,145 solve sed,0 sed,,1 ! Y-direction base excitation freq freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2 freq,35,40,588 sv,0.02,266.7,580.7,580.7,466.7,792,792,293.3333,516.7,516.7 sv,0.02,253.3,232.4,96.7 solve sed,,0 sed,,,1 ! Z-direction base excitation freq freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2 freq,35,40,588 sv,0.02,400,871,871,700,1188,1188,440,775,775 sv,0.02,380,348.6,145 solve sed,,,0 fini /post1 /input,,mcom prdi finish
/prep7 et,1,pipe288,,,3 ! PIPE288 using cubic shape function et,2,mass21 ! MASS21 ! *** Section and Real Constants sectype,1,pipe secdata,2.37500000,0.15400000,14 r,2,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,3,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,4,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,5,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,6,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,7,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,8,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,9,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,10,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,11,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,12,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,13,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,14,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,15,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 ! *** Nodes n,1,0.0,-30.00 n,2,27.25,-30.00 n,3,27.25,-30.00,17.250 n,4,0.0,-30.00,17.250 n,5,0.0,18.625,17.250 n,6,0.0,18.625,8.625 n,7,0.0,18.625 n,8,8.625,18.625, n,9,18.625,18.625 n,10,27.25,18.625 n,11,27.25,18.625,8.625 n,12,27.25,18.625,17.250 n,13,18.625,18.625,17.250 n,14,8.625,18.625,17.250 n,15,0.0,-80.00 n,16,27.25,-80.00 n,17,27.25,-80.00,17.250 n,18,0.0,-80.00,17.25 ! *** Mesh of Straight Pipe: Tangent Elements mat,1 type,1 secnum,1 en,1,15,1 en,2,1,7 en,3,7,6 en,4,6,5 en,5,5,4 en,6,4,18 en,7,16,2 en,8,2,10 en,9,10,11 en,10,11,12 en,11,12,3 en,12,3,17 en,13,12,13 en,14,13,14 en,15,14,5 en,16,7,8 en,17,8,9 en,18,9,10 ! *** Mass Elements mat,1 type,2 real,2 en,19,1 real,3 en,20,2 real,4 en,21,3 real,5 en,22,4 real,6 en,23,5 real,7 en,24,6 real,8 en,25,7 real,9 en,26,8 real,10 en,27,9 real,11 en,28,10 real,12 en,29,11 real,13 en,30,12 real,14 en,31,13 real,15 en,32,14 ! *** Component for Support Nodes nsel,s,node,,15 nsel,a,node,,16 nsel,a,node,,17 nsel,a,node,,18 cm,fixedsu,node allsel,all ! *** Material mp,ex,1,27899996.8 mp,nuxy,1,0.3 mp,dens,1,2.587991718e-10 ! *** Constraints d,15,all,0 d,16,all,0 d,17,all,0 d,18,all,0 allsel,all finish ! *** Modal Analysis ! ****************** /solution antype,modal modopt,lanb,5 mxpand,,,,yes ! request the element results solve save ! save the database for future reuse of MODE file finish /clear,nostart ! clear the database to start a new analysis /com,***** X direction ************* /prep7 resume,,db ! resume the database from the modal analysis finish /solution antype,spectr spopt,sprs,,,yes ! reuse the existing mode file dmprat,0.02 grp,0.001 svtyp,2 sed,1 ! X-direction base excitation freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2 freq,35,40,588 sv,0.02,400,871,871,700,1188,1188,440,775,775 sv,0.02,380,348.6,145 solve sed,0 finish /post1 /input,,mcom prdi finish /copy,,mcom,,xdir,mcom /clear,nostart /com,***** Y direction ************* /prep7 resume,,db ! resume the database from the modal analysis finish /solution antype,spectr spopt,sprs,,,yes ! reuse the existing mode file dmprat,0.02 grp,0.001 svtyp,2 sed,,1 ! Y-direction base excitation freq freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2 freq,35,40,588 sv,0.02,266.7,580.7,580.7,466.7,792,792,293.3333,516.7,516.7 sv,0.02,253.3,232.4,96.7 solve sed,,0 finish /post1 /input,,mcom prdi finish /copy,,mcom,,ydir,mcom /clear,nostart /com,***** Z direction ************* /prep7 resume,,db ! resume the database from the modal analysis finish /solution antype,spectr spopt,sprs,,,yes ! reuse the existing mode file dmprat,0.02 grp,0.001 svtyp,2 sed,,,1 ! Z-direction excitation freq freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2 freq,35,40,588 sv,0.02,400,871,871,700,1188,1188,440,775,775 sv,0.02,380,348.6,145 solve sed,,,0 finish /post1 /input,,mcom prdi finish /copy,,mcom,,zdir,mcom
6.4.4. Single-Point Response Spectrum Analysis on a Piping Structure with Excitation
Along X, Y, and Z Directions, missing mass effect, Elcalc
= YES and SpecCum = NO on
SPOPT command
/prep7
et,1,pipe288,,,3 ! PIPE288 using cubic shape function
et,2,mass21 ! MASS21
! *** Section and Real Constants
sectype,1,pipe
secdata,2.37500000,0.15400000,14
r,2,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0
r,3,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0
r,4,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0
r,5,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0
r,6,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0
r,7,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
r,8,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0
r,9,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
r,10,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
r,11,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0
r,12,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
r,13,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0
r,14,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
r,15,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
! *** Nodes
n,1,0.0,-30.00
n,2,27.25,-30.00
n,3,27.25,-30.00,17.250
n,4,0.0,-30.00,17.250
n,5,0.0,18.625,17.250
n,6,0.0,18.625,8.625
n,7,0.0,18.625
n,8,8.625,18.625,
n,9,18.625,18.625
n,10,27.25,18.625
n,11,27.25,18.625,8.625
n,12,27.25,18.625,17.250
n,13,18.625,18.625,17.250
n,14,8.625,18.625,17.250
n,15,0.0,-80.00
n,16,27.25,-80.00
n,17,27.25,-80.00,17.250
n,18,0.0,-80.00,17.25
! *** Mesh of Straight Pipe: Tangent Elements
mat,1
type,1
secnum,1
en,1,15,1
en,2,1,7
en,3,7,6
en,4,6,5
en,5,5,4
en,6,4,18
en,7,16,2
en,8,2,10
en,9,10,11
en,10,11,12
en,11,12,3
en,12,3,17
en,13,12,13
en,14,13,14
en,15,14,5
en,16,7,8
en,17,8,9
en,18,9,10
! *** Mass Elements
mat,1
type,2
real,2
en,19,1
real,3
en,20,2
real,4
en,21,3
real,5
en,22,4
real,6
en,23,5
real,7
en,24,6
real,8
en,25,7
real,9
en,26,8
real,10
en,27,9
real,11
en,28,10
real,12
en,29,11
real,13
en,30,12
real,14
en,31,13
real,15
en,32,14
! *** Component for Support Nodes
nsel,s,node,,15
nsel,a,node,,16
nsel,a,node,,17
nsel,a,node,,18
cm,fixedsu,node
allsel,all
! *** Material
mp,ex,1,27899996.8
mp,nuxy,1,0.3
mp,dens,1,2.587991718e-10
! *** Constraints
d,15,all,0
d,16,all,0
d,17,all,0
d,18,all,0
allsel,all
finish
! *** Modal Analysis
! ******************
/solution
antype,modal
modopt,lanb,5
mxpand,,,,yes ! request the element results
solve ! last set number is 5 in .rst file
save ! save the database
finish
!** Spectrum Analysis
!*********************
/solution
antype,spectr
spopt,sprs,,yes ! request element result calculations, with SpecCum = NO by default
dmprat,0.02
grp,0.001 ! modes combination method
svtyp,2
sed,1 ! X-direction base excitation
freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2
freq,35,40,588
sv,0.02,400,871,871,700,1188,1188,440,775,775
sv,0.02,380,348.6,145
mmass,on,1 ! missing mass activated
solve ! missing mass response is at set 6 in .rst
! combined solution is temporarily at set 7 in .rst; deleted later by issuing FINISH
sed,0
sed,,1 ! Y-direction base excitation
freq
freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2
freq,35,40,588
sv,0.02,266.7,580.7,580.7,466.7,792,792,293.3333,516.7,516.7
sv,0.02,253.3,232.4,96.7
solve ! missing mass response is at set 8 in .rst
! combined solution is temporarily at set 9 in .rst; deleted later by issuing FINISH
sed,,0
sed,,,1 ! Z-direction base excitation
freq
freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2
freq,35,40,588
sv,0.02,400,871,871,700,1188,1188,440,775,775
sv,0.02,380,348.6,145
solve ! missing mass response is at set 10 in .rst
! combined solution for the 3 spectra is at set 11 in .rst
fini ! FINISH command activates the deletion of sets 7 and 9
/post1
set,last ! or set,,,,,,,9; 9 = 11 sets - 2 deleted sets
fsum
finish
6.4.5. Single-Point Response Spectrum Analysis on a Piping Structure with Excitation
Along X, Y, and Z Directions, missing mass effect, Elcalc = YES and SpecCum = YES on
SPOPT command: method 1
/prep7 et,1,pipe288,,,3 ! PIPE288 using cubic shape function et,2,mass21 ! MASS21 ! *** Section and Real Constants sectype,1,pipe secdata,2.37500000,0.15400000,14 r,2,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,3,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,4,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,5,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0 r,6,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,7,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,8,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,9,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,10,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,11,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,12,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,13,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0 r,14,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 r,15,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0 ! *** Nodes n,1,0.0,-30.00 n,2,27.25,-30.00 n,3,27.25,-30.00,17.250 n,4,0.0,-30.00,17.250 n,5,0.0,18.625,17.250 n,6,0.0,18.625,8.625 n,7,0.0,18.625 n,8,8.625,18.625, n,9,18.625,18.625 n,10,27.25,18.625 n,11,27.25,18.625,8.625 n,12,27.25,18.625,17.250 n,13,18.625,18.625,17.250 n,14,8.625,18.625,17.250 n,15,0.0,-80.00 n,16,27.25,-80.00 n,17,27.25,-80.00,17.250 n,18,0.0,-80.00,17.25 ! *** Mesh of Straight Pipe: Tangent Elements mat,1 type,1 secnum,1 en,1,15,1 en,2,1,7 en,3,7,6 en,4,6,5 en,5,5,4 en,6,4,18 en,7,16,2 en,8,2,10 en,9,10,11 en,10,11,12 en,11,12,3 en,12,3,17 en,13,12,13 en,14,13,14 en,15,14,5 en,16,7,8 en,17,8,9 en,18,9,10 ! *** Mass Elements mat,1 type,2 real,2 en,19,1 real,3 en,20,2 real,4 en,21,3 real,5 en,22,4 real,6 en,23,5 real,7 en,24,6 real,8 en,25,7 real,9 en,26,8 real,10 en,27,9 real,11 en,28,10 real,12 en,29,11 real,13 en,30,12 real,14 en,31,13 real,15 en,32,14 ! *** Component for Support Nodes nsel,s,node,,15 nsel,a,node,,16 nsel,a,node,,17 nsel,a,node,,18 cm,fixedsu,node allsel,all ! *** Material mp,ex,1,27899996.8 mp,nuxy,1,0.3 mp,dens,1,2.587991718e-10 ! *** Constraints d,15,all,0 d,16,all,0 d,17,all,0 d,18,all,0 allsel,all finish ! *** Modal Analysis ! ****************** /solution antype,modal modopt,lanb,5 mxpand,,,,yes ! request the element results solve ! last set number is 5 in .rst file save ! save the database finish !** Spectrum Analysis !********************* /solution antype,spectr spopt,sprs,,yes,,yes ! request element result calculations, with SpecCum = YES dmprat,0.02 grp,0.001 ! modes combination method svtyp,2 sed,1 ! X-direction base excitation freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2 freq,35,40,588 sv,0.02,400,871,871,700,1188,1188,440,775,775 sv,0.02,380,348.6,145 mmass,on,1 ! missing mass activated solve ! missing mass response is at set 6 in .rst ! combined solution is at set 7 in .rst ; deleted later sed,0 sed,,1 ! Y-direction base excitation freq freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2 freq,35,40,588 sv,0.02,266.7,580.7,580.7,466.7,792,792,293.3333,516.7,516.7 sv,0.02,253.3,232.4,96.7 solve ! missing mass response is at set 8 in .rst ! combined solution is at set 9 in .rst ; deleted later as set 8 = 9-1 because set 7 will be deleted first sed,,0 sed,,,1 ! Z-direction base excitation freq freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2 freq,35,40,588 sv,0.02,400,871,871,700,1188,1188,440,775,775 sv,0.02,380,348.6,145 solve ! missing mass response is at set 10 in .rst ! combined solution for the 3 spectra is at set 11 in .rst fini /aux3 ! delete intermediate sets in .rst file,,rst delete,set,7 compress delete,set,8 compress fini /post1 set,last ! or set,,,,,,,9 ; 9 = 11 sets - 2 deleted sets fsum finish
6.4.6. Single-Point Response Spectrum Analysis on a Piping Structure with Excitation
Along X, Y, and Z Directions, missing mass effect, Elcalc
= YES on SPOPT command: method 2
/prep7
et,1,pipe288,,,3 ! PIPE288 using cubic shape function
et,2,mass21 ! MASS21
! *** Section and Real Constants
sectype,1,pipe
secdata,2.37500000,0.15400000,14
r,2,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0
r,3,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0
r,4,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0
r,5,0.447000518e-01,0.447000518e-01,0.447000518e-01,0.0,0.0,0.0
r,6,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0
r,7,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
r,8,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0
r,9,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
r,10,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
r,11,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0
r,12,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
r,13,0.432699275e-01,0.432699275e-01,0.432699275e-01,0.0,0.0,0.0
r,14,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
r,15,0.893995859e-02,0.893995859e-02,0.893995859e-02,0.0,0.0,0.0
! *** Nodes
n,1,0.0,-30.00
n,2,27.25,-30.00
n,3,27.25,-30.00,17.250
n,4,0.0,-30.00,17.250
n,5,0.0,18.625,17.250
n,6,0.0,18.625,8.625
n,7,0.0,18.625
n,8,8.625,18.625,
n,9,18.625,18.625
n,10,27.25,18.625
n,11,27.25,18.625,8.625
n,12,27.25,18.625,17.250
n,13,18.625,18.625,17.250
n,14,8.625,18.625,17.250
n,15,0.0,-80.00
n,16,27.25,-80.00
n,17,27.25,-80.00,17.250
n,18,0.0,-80.00,17.25
! *** Mesh of Straight Pipe: Tangent Elements
mat,1
type,1
secnum,1
en,1,15,1
en,2,1,7
en,3,7,6
en,4,6,5
en,5,5,4
en,6,4,18
en,7,16,2
en,8,2,10
en,9,10,11
en,10,11,12
en,11,12,3
en,12,3,17
en,13,12,13
en,14,13,14
en,15,14,5
en,16,7,8
en,17,8,9
en,18,9,10
! *** Mass Elements
mat,1
type,2
real,2
en,19,1
real,3
en,20,2
real,4
en,21,3
real,5
en,22,4
real,6
en,23,5
real,7
en,24,6
real,8
en,25,7
real,9
en,26,8
real,10
en,27,9
real,11
en,28,10
real,12
en,29,11
real,13
en,30,12
real,14
en,31,13
real,15
en,32,14
! *** Component for Support Nodes
nsel,s,node,,15
nsel,a,node,,16
nsel,a,node,,17
nsel,a,node,,18
cm,fixedsu,node
allsel,all
! *** Material
mp,ex,1,27899996.8
mp,nuxy,1,0.3
mp,dens,1,2.587991718e-10
! *** Constraints
d,15,all,0
d,16,all,0
d,17,all,0
d,18,all,0
allsel,all
finish
! *** Modal Analysis
! ******************
/solution
antype,modal
modopt,lanb,5
mxpand,,,,yes ! request the element results
solve
save ! save the database
finish
!** Spectrum Analysis
!*********************
/solution
antype,spectr
spopt,sprs,,yes ! request element result calculations
dmprat,0.02
svtyp,2
sed,1 ! X-direction base excitation
freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2
freq,35,40,588
sv,0.02,400,871,871,700,1188,1188,440,775,775
sv,0.02,380,348.6,145
mmass,on,1 ! missing mass activated
solve ! missing mass response is at set 6 in .rst
sed,0
sed,,1 ! Y-direction base excitation
freq
freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2
freq,35,40,588
sv,0.02,266.7,580.7,580.7,466.7,792,792,293.3333,516.7,516.7
sv,0.02,253.3,232.4,96.7
solve ! missing mass response is at set 7 in .rst
sed,,0
sed,,,1 ! Z-direction base excitation
freq
freq,3.1,4,5,5.8,7.1,8.8,11,14.1,17.2
freq,35,40,588
sv,0.02,400,871,871,700,1188,1188,440,775,775
sv,0.02,380,348.6,145
solve ! missing mass response is at set 8 in .rst
fini
/solution ! finalize spectrum analysis with mode combination command
antype,spectr
spopt,sprs,,yes, ! request element result calculations
grp,0.001
solve ! combined solution for the 3 spectra is at set 9 in .rst
fini
/post1
set,last ! or set,,,,,,,9
fsum
finish
Radius = 7 Height = 21 Thickness = 0.015 ElemSize = 2.0 Dens_Fluid = 1000 Sonc_Fluid = 1500 Ex_Solid = 1.95e11 PRXY_Solid = 0.3 Dens_Solid = 7850 /PREP7 LOCAL,12,0,0,0,0, ,-90, ,1,1, CSYS,12 WPCSYS,-1 CSYS,0 CYLIND,Radius,0,0,Height,0,360, ET,1,220,0,0 MP,DENS,1,Dens_Fluid MP,SONC,1,Sonc_Fluid ET,2,281 MP,EX,2,Ex_Solid MP,DENS,2,Dens_Solid MP,PRXY,2,PRXY_Solid SECTYPE,2,SHELL SECDATA,Thickness,2 ESIZE,ElemSize TYPE,1 MAT,1 SECNUM,1 VSEL,,,,1 VSWEEP,ALL TYPE,2 MAT,2 SECNUM,2 ASEL,S,,,1 ASEL,A,,,3 ASEL,A,,,4 NSLA,S,1 ESURF ! constrain base plate in horizontal directions DA,1,UX,0 DA,1,UZ,0 DA,2,PRES,0 SFA,1,,FSI SFA,3,,FSI SFA,4,,FSI ALLSEL,ALL ! spring supports et,3,COMBIN14 keyopt,3,2,2 ! UY r,3,1e+10 nsel,,loc,y,0 type,3 real,3 ngen,2,200000,all,,0,0,0 ! coincident /nopr eintf /gopr nsel,,node,,200000,300000 ! constrain base nodes d,all,all allsel save finish /solu ANTYPE,MODAL MODOPT,UNSYM,20,4.1,20,REAL,,BOTH MXPAND,20 SOLVE FINI /post1 /out set,list /out,scratch fini /solu antype,spectrum spopt,sprs betad,0.002 svtyp,2,9.810 ! acceleration spectra, m/sec^2 rock,,10.443,,0.15, ! Center of rotation, CGY = 10.443, ! angular component of the rocking, OMY = 0.15 sed,1.1, ! excitation in X - Direction /com, ---------------------------------------------------------- /com, Note: Rocking is present, so the direction of excitation /com, calculated from the SED and ROCK commands scales the input /com, spectrum values. /com, ---------------------------------------------------------- freq,4,4.5,5,6 sv,,0.1,0.2,0.2,0.1 solve fini /com, Spectrum Combination /solu antype,spectr spopt,sprs grp,0.001,disp solve fini /out,scratch /post1 /input,,mcom /view,,1,1,1 /show,png,rev plnsol,u,y plnsol,pres /show,close fini