在y轴正向施加几何位移后为什么在轴向压力作用下位移反而向下

shimly521

fini
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MP,PRXY,,0.3
ET,1,PIPE16          ! ELASTIC STRAIGHT PIPE
MP,EX,1,2e11      ! DEFINE MODULUS OF ELASTICITY
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N,1                  ! BEGIN NODE DEFINITION
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n,5,1,0.00002/3
N,6,1.25,0.00005/6
n,7,1.5,0.00001
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/SOLU
antype,0
D,1,ALL            ! CONSTRAIN ALL DOF'S
f,7,fx,-35000000
nlgeom,on
nsubst,500
arclen,on
allsel
outres,all,all
solve
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set,last
pldisp,2

beidoumax

楼主的解答是正确的，按照材料力学的压杆稳定理论出现了位移是因为你的力达到了临界载荷，按一端固定一端自由的临界压力为　　　　Fcr=pi*pi*E*I/(4L*L)   其中pi=3.1415926...