problem description
title="3d Beam Sample Problem (Logan ex. 6.9, p.250)" nodes=4 elements=3 

nodes
1 	x=240	y=0	z=120	constraint=free	force=point
2	x=0	y=0	z=240	constraint=fixed
3	x=0	y=0	z=0
4	x=240	

beam3d elements
1 nodes=[1,2] material=steel
2 nodes=[1,3]
3 nodes=[1,4]

material properties
steel e=30e6 g=12e6 j=110 iy=400 iz=400 a=1

constraints
free  tx=u ty=u tz=u rx=u ry=u rz=u
fixed tx=c ty=c tz=c rx=c ry=c rz=c

forces
point fy=-100e3	

end
