problem description
title="Quadrilateral Triangle w/Distributed Load (Logan #7.10, p.309)" 
nodes=4 elements=2

nodes
1 x=0 y=0 z=0	constraint=pin
2 x=0 y=10 	constraint=pin
3 x=20 y=10	constraint=free
4 x=20 y=0	constraint=free

quad_PlaneStress elements
1 nodes=[1,3,2,2] material=steel
2 nodes=[1,4,3,3] material=steel load=shear

material properties
steel t=1 e=30e6 nu=0.30

distributed loads
shear direction=GlobalY values=(2,-1000) (3,-1000)

constraints
pin	tx=c ty=c
free	tx=u ty=u

end
