管道振动优化设计

管道

下面是所建管道模型(命令流)，需要用优化理论，在管道某处加约束，使其管道振动的位移、速度、加速度最小。希望得到诸位的指点。
/FILN,12256
/TITLE,BS
/PREP7
MP,EX,1,216E9
MP,PRXY,1,0.3
MP,DENS,1,,7820
PSPEC,1,,,0.18,0.04
PTEMP,100,110
PPRES,120E6
BRANCH,1,127.37,101.35,5.07
RUN,,,-1.165,6,,,1
*GET,maxnode,NODE,,NUM,MAX,,,
D,maxnode,,,,,Ux,Uy,Uz,rotx,roty,rotz
RUN,,,-0.505,3,,,1
*GET,maxnode,NODE,,NUM,MAX,,,
FLANGE,maxnode,0.065,150,1,1,,,
RUN,,,-2,1,,,1
*GET,maxelem,ELEM,,NUM,MAX,,
RUN,-2,,,1,,,1
BEND,maxelem,maxelem+1,1.2,9,,1
PSPEC,1,,,0.5751,0.2375
RUN,-0.065