Using ANSYS - 2D, 2 element Beam model with concentrated masses at the free nodes

```/batch
/FILNAM,beam2
/title 2D Beam Sample Problem

! Two element 2D beam Sample Problem  4-14-99   KLL
! 2 elements with concentrated mass/inertia at free nodes

/prep7
n,  1,  0.0,  0.0         ! Node 1 is located at (0.0, 0.0)
n,  2,  1.0,  0.0
n,  3,  2.0,  0.0

et, 1, beam3              ! Element type; no.1 is beam3, 2D beam element

et, 2, mass21, 0, 0, 3    ! Element type 2 is mass/inertia
! keyopt(3) = 3 means data = mass, inertia
mp, ex, 1, 3.e7           ! Material Property, Elastic modulus no. 1; psi
mp, prxy, 1, 0.3          ! Poisson's ratio
mp, dens, 1, 0.736e-3     ! Mass density; (lbf/in^3)/(in/sec^2)

! In ANSYS documentation the symbol Izz is used with different meanings.

! Beam real constant set 1 for a 0.5 x 0.375 rectangular xsctn.
! Area, Izz (flexural Inertia), height 'h' as in sigma = Mc/I, c = h/2
! A = 0.1875 in^2, Izz = 0.0022 in^4, h = 0.375 in
! (Note: here Izz is the area moment of inertia, length^4)

r, 1, 0.1875, 0.0022, 0.375

! 2D Concentrated mass/inertia real data
! mass = 0.2 lbf/(in/sec^2), Izz = 0.075 (lbf-in^2)/(in/sec^2)
! (Note: here Izz is the mass moment of inertia, mass x length^2)

r, 2, .2, .075

! beam elements
type, 1
real, 1
en,  1,  1,  2           ! Element Number 1 (beam) connects nodes 1 & 2
en,  2,  2,  3

! mass elements
type, 2
real, 2

en, 3, 2                 ! Element Number 3 (mass/inertia) is at node 2
en, 4, 3

d, 1, ux, 0.             ! Displacement at node 1 in x-dir is zero
d, 1, uy, 0.
d, 1, rotz, 0.           ! Rotation about z axis at node 1 is zero
```

Last update 4-14-99