602
16 Computer Programs in Vibration Analysis
Table 16.9 (continued)
subroutine search(ak,nb1,ist,iend,gstif)
dimension ak(3300000),gstif(3300000)
do 20 ii=1,nb1
if(ak(ii))10,20,10
10 ibl=ii
go to 30
20 continue
ibl=nb1
30 continue
icount=nb1-ibl+1
iend=iend+icount
do 40 ii=ist,iend
jj=ii-ist+ibl
gstif(ii)=ak(jj)
40 continue
ist=ist+icount
return
end
c********************************************************************
c********************************************************************
c
subroutine bound starts
c
c********************************************************************
subroutine bound (nbon,i,j,k,stifo,kind,nd)
dimension stifo(1)
rigid=1.0e20
go to (40,30,20,10,5), nbon+1
5
do 7 ii=i,j,k
stifo(kind(ii+nd))=rigid
stifo(kind(ii+4-nd))=rigid
7
continue
return
10
do 15 ii=i,j,k
stifo(kind(ii+nd))=rigid
stifo(kind(ii+2))=rigid
15
continue
go to 40
20
do 25 ii=i,j,k
stifo(kind(ii))=rigid
stifo(kind(ii+1))=rigid
stifo(kind(ii+2))=rigid
stifo(kind(ii+4-nd))=rigid
25
continue
go to 40
30
do 35 ii=i,j,k
stifo(kind(ii))=rigid
stifo(kind(ii+1+nd))=rigid
35
continue
40
continue
return
end
c**************************************************************************
C
end of bound
c**************************************************************************
The computer program consists of a number of subroutines. The element stiffness matrix STIFF and the element mass matrix ELMAS are evaluated by Gauss’s
numerical integration. Two-point reduced integration is to be used for isoparametric
quadratic element—the Gauss point values are obtained in the subroutine GACUV.
The element mass matrix is diagonal and contains the diagonal elements based on
the consistent mass matrix which has been proportionately altered on the basis of
the total plate element mass. The elements of the mass matrix corresponding to
rotation terms are not considered. Subroutine BOUND takes care of the boundary