!
!
!   TITLE:  harmonic_example.mac (SOLVE)
!
! Two masses attached by 3 springs (section 4.6 of "4 Harmonic Response
! Analysis", pg. 4-19) modified to 2 masses of 0.5 and 1.0 lb-sec^2/in with
! damping.  Mass 1 is vibrated sinusoidally with an amplitude of 200 lb
! in a frequency range from 0 to 7.5 Hz.  A damping ratio (DMPRAT) of
! 0.05 is used for this system.  A FULL harmonic analysis is calculated for 
! frequency steps (fstep) of 50 Hz increments.
!
!  
/prep7
/title,harmonic response of a two-mass-spring system

et,1,combin14,,,2
et,2,mass21,,,4
et,3,mass21,,,4
r,1,200         ! spring constant = 200
r,2,.5          ! mass = 0.5
r,3,1.0
n,1
n,4,1
fill
e,1,2
e,2,3
e,3,4
type,2
real,2
e,2         ! mass element
type,3
real,3
e,3         ! mass element
finish
!
/solu
antype,harmic       ! harmonic response element
hropt,full      ! full harmonic response
hrout,off       ! print results as amplitudes & phase angles
outpr,basic,1
nsubst,50       ! 30 intervals in range
harfrq,0,7.5        ! frequency range 0 to 7.5Hz
kbc,1           ! step boundary condition
d,1,uy,,,4      ! constrain all 44 DOF
d,1,ux,,,4,3        ! constrain nodes 1 and 4 in ux
dmprat,.05
f,2,fx,200
solve
finish
!
/post26
nsol,2,2,u,x,2ux    ! store ux displacements
nsol,3,3,u,x,3ux
/grid,1
/axlab,y,disp       ! Y-axis label
plvar,2,3       ! plot variables 2 and 3
finish