『求助』如何加旋转约束啊，急急！（有代码）

/Prep7
ANTYPE,0
*SET,Ro,0.2285
*SET,Thickness,8.6300e-3
*SET,Ri,Ro-Thickness
*SET,Mid_Radius,Ro-Thickness/2
*SET,Length,20.00
*SET,P,10e6
ET,1,SHELL181
MP,EX,1,209.00e9 !!!!!!!!
MP,NUXY,1,0.30
MP,DENS,1,20.3397e3
R,1,Thickness
K,1
K,2,0,0,Length
circle,1,Mid_Radius
L,1,2
LESIZE,5,,,300
ADRAG,1,2,3,4,,,5
ESIZE,0.05,0
MSHKEY,1
AMESH,ALL
CSYS,1
LSEL,S,LINE,,1,4,1,0
LSEL,A,LINE,,6
LSEL,A,LINE,,9
LSEL,A,LINE,,11
LSEL,A,LINE,,13
NSLL,S,1
NROTAT,ALL
D,ALL,UY,,,,,uz !!!!!!!!
LSEL,S,LINE,,1,4,1,0
LSEL,A,LINE,,6
LSEL,A,LINE,,9
LSEL,A,LINE,,11
LSEL,A,LINE,,13
SFL,ALL,PRES,-P*Ro/2/Thickness*0.3*(Ro*Ro-Ri*Ri)/Mid_Radius
ALLSEL,ALL,ALL
CSYS,0
SFA,ALL,1,PRES,P
ALLSEL,ALL,ALL
ACEL,,9.8
FINISH
/SOLU
SOLVE
FINISH
命令流是别人写的，我看不懂啊！ 现在急需要把管道改成简支，也就是把y和z得旋转约束住
该怎样做！！急啊，谢谢了，希望高手指点