Civil Engineering Reference
In-Depth Information
4.0
1
16
4
1.0
2
17
18
5
3
E=1 kN/m
2
n
=0.3
r
=1 t/m
3
F= cos
w
t
nxe nye cg_tol cg_limit
3 1 1.0e-5 50
np_types
1
prop(e,v,rho)
1.0 0.3 1.0
etype (not needed)
x_coords, y_coords
0.0 1.33333 2.66667 4.0
0.0 -1.0
dtim nstep theta npri nres fm fk
1.0 20 0.5 1 18 0.005 0.272
nr,(k,nf(:,k),i=1,nr)
3
1 0 0 2 0 0 3 0 0
loaded_nodes,(node(i),val(i,:),i=1,loaded_nodes)
1
18 0.0 1.0
Figure 11.16
Mesh and data for Program 11.6 example
The element stiffness matrices
km
are stored as
storkm
with the mass matrices
mm
as
stormm
. The same example analysed by Programs 11.2, 11.3, and 11.4 is repeated, with
the data given in Figure 11.16. The results shown in Figure 11.17 are essentially the same
as those obtained using a direct solver shown in Figure 11.10. It may also be noted from
these results that this version of pcg solution is taking approximately
neq/2
iterations to
converge (where
neq
is the number of equations), a similar convergence rate as was usual
in Chapters 5 and 6. In Chapter 8, the convergence rate was much quicker at approximately
neq/10
. Fortunately, as problem sizes increase the iteration count, as a proportion of
neq
,
drops very rapidly.
