*heading
 Simple eigenvalue analysis of elastic-plastic joint element.
 A diagonal stiffness is used.  One node is constrained and masses
 are placed on the other.  This produces 3 independent single-dof 
 systems with frequencies 3,4,5 rad/time for systems on dof
 1,2,6 respectively.
**
**
*node
1,0,0,0.
10,0,0,0.
*element,elset=joint,type=joint2d
1,10,1
**
*element,elset=mass,type=mass
10,10
*element,elset=rot,type=rotaryi
11,10
**
*orientation,name=orientation1
0,1,0,1,0,0
**
*epjoint,elset=joint,orientation=orientation1
*joint elasticity,ndim=2, moduli=gen
9.,0,16.,0,0,25.
**
*mass,elset=mass
1.,
*rotary inertia,elset=rot
0,0,1
**
*step
*frequency, eigensolver=lanczos
3, , 
*BOUNDARY
1,encastre
10,3,5
*output,field
*node output
u,rf
*element output,elset=joint
s,e
*end step
**
**