求助关于转动的问题

我做了一个简单的模型，就是让一个矩形块绕着自己的中心轴旋转运动（中心轴在矩形块的中间）也就是z轴），但是求解结果总是不能绕着中心轴运动，是什么原因呢？
谢谢大家帮忙！我的命令和模型图如下：
/PREP7
!*
ET,1,SOLID45
!*
!*
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,EX,1,,8e10
MPDATA,PRXY,1,,0.3
MPTEMP,,,,,,,,
MPTEMP,1,0
MPDATA,DENS,1,,8900
BLOCK,-0.01,0.01,-0.01,0.01,0,0.01,
/VIEW,1,1,2,3
/ANG,1
/REP,FAST
WPSTYLE,,,,,,,,0
FLST,5,8,4,ORDE,2
FITEM,5,1
FITEM,5,-8
CM,_Y,LINE
LSEL, , , ,P51X
CM,_Y1,LINE
CMSEL,,_Y
!*
LESIZE,_Y1, , ,20, , , , ,1
!*
FLST,5,4,4,ORDE,2
FITEM,5,9
FITEM,5,-12
CM,_Y,LINE
LSEL, , , ,P51X
CM,_Y1,LINE
CMSEL,,_Y
!*
LESIZE,_Y1, , ,5, , , , ,1
!*
/UI,MESH,OFF
CM,_Y,VOLU
VSEL, , , , 1
CM,_Y1,VOLU
CHKMSH,'VOLU'
CMSEL,S,_Y
!*
VSWEEP,_Y1
!*
CMDELE,_Y
CMDELE,_Y1
CMDELE,_Y2
!*
/DIST,1,0.924021086472,1
/REP,FAST
/DIST,1,0.924021086472,1
/REP,FAST
/DIST,1,1.08222638492,1
/REP,FAST
/DIST,1,1.08222638492,1
/REP,FAST
VSEL,S, , , 1
ESLV,S
CM,aa,ELEM
CSYS,1
FLST,2,2646,1,ORDE,2
FITEM,2,1
FITEM,2,-2646
NROTAT,P51X
FINISH
/SOL
CMOMEGA,AA,0,0,100,,,, , , ,0
VSEL,S, , , 1
NSLV,S,1
NSEL,R,LOC,X,0
NSEL,R,LOC,Y,0
NPLOT
/VIEW,1,1
/ANG,1
/REP,FAST
/VIEW,1,,1
/ANG,1
/REP,FAST
/ANG,1,-30,XS,1
/REP,FAST
/ANG,1,-30,XS,1
/REP,FAST
/ANG,1,-30,XS,1
/REP,FAST
/ANG,1,-30,XS,1
/REP,FAST
FLST,2,6,1,ORDE,4
FITEM,2,181
FITEM,2,542
FITEM,2,1923
FITEM,2,-1926
!*
/GO
D,P51X, ,0, , , ,UY, , , , ,
FLST,2,6,1,ORDE,4
FITEM,2,181
FITEM,2,542
FITEM,2,1923
FITEM,2,-1926
!*
/GO
D,P51X, ,00, , , ,UX, , , , ,
FINISH
/POST1
FINISH
/SOL
!*
ANTYPE,0
ANTYPE,0
NLGEOM,1
OUTRES,ERASE
OUTRES,ALL,ALL
TIME,1
ALLSEL,ALL
VPLOT
EPLOT
/STATUS,SOLU
SOLVE
FINISH