Civil Engineering Reference
In-Depth Information
Dynamic real arrays:
diag
global lumped mass vector
ell
element lengths vector
kh
element stiffness matrix
km
element stiffness matrix
ku
global stiffness matrix
kv
global stiffness matrix
mm
element lumped mass matrix
prop
element properties matrix
rrmass
reciprocal square rooted global lumped mass matrix
udiag
working space vector
This program illustrates a natural frequency analysis of a typical “string” of beam
elements, and can be thought of as an extension to Program 4.3. The natural frequencies
of the simple cantilever shown in Figure 10.1 are to be found. The first line of data gives
the number of elements
nels
which equals 5 in this case. The next line gives the number
of properties
np types
which for a uniform beam equals 1. The two properties are then
read in as the flexural stiffness
EI
read as 0.08333 and the mass per unit length
ρA
read
4.0
EI=0.08333
r
A=1.0
1
2
3
4
5
1
2
3
4
5
6
nels
5
np_types
1
prop(ei,rhoa)
0.08333 1.0
etype(not needed)
ell
0.8 0.8 0.8 0.8 0.8
nr,(k,nf(:,k),i=1,nr)
1
1 0 0
nmodes
3
Figure 10.1 Mesh and data for Program 10.1 example
