一段小程序，求大神帮改改

DMAX. SMAX都显示是0.估计是我提取的不对。。求帮改改，模型就是个小轴
D1=10
D2=15
D3=20
D4=15
YOUNG=2.1E5
DENSITY=8000
P=100000
/PREP7
MP,EX,1,YOUNG
MP,NUXY,1,0.3
MP,DENS,1,DENSITY
ET,1,SOLID92
CYL4,0,0,D1,0,0,360,10
WPOFFS,0,0,10
CYL4,0,0,D2,0,0,360,10
WPOFFS,0,0,10
CYL4,0,0,D3,0,0,360,20
WPOFFS,0,0,20
CYL4,0,0,D4,0,0,360,10
WPOFFS,0,0,-40
VADD,ALL
VPLOT
ESIZE,3
VMESH,ALL
EPLOT
FINISH
/SOLU
NSEL,S,LOC,Z,0
SF,ALL,PRES,P
NSEL,S,LOC,Z,50
SF,ALL,PRES,P
ALLSEL
SOLVE
FINISH
/POST1
NSEL,ALL
NSORT,U,Z,0,0,ALL
*GET,DMAX,SORT,0,MAX
NSORT,S,EQV,0,0,ALL
*GET,SMAX,SORT,0,MAX
FINISH