cylsh_buck.inp:Input file for the linear buckling analysis

*heading
Input file for the linear buckling analysis.
*node,system=c
1,5.0,0.0,0.0
240,5.0,-1.5,0.0
4801,5.0,0.0,2
5040,5.0,-1.5,2
*ngen,line=c,nset=bottom
1,240,1,,0.0,0.0,0.0,0.0,0.0,1.0
** 圆弧所在平面的法线是Z轴
*ncopy,new set=top,old set=bottom,shift,change number=4800
** 复制bottom节点，沿Z轴平移2
0.0,0.0,2
0.0,0.0,0.0,0.0,0.0,1.0,0.0
*nfill
bottom,top,20,240
*element,type=s4
1,1,2,242,241
240,240,1,241,480
*elgen,elset=cylinder
1,239,1,1,20,240,240
240,1,,,20,240,240
*shell section, elset=cylinder, material=mat_1
0.01,
*material,name=mat_1
*elastic
30e+06,0.3
*nset,nset=ends
bottom,top
*transform,type=c,nset=ends
** 为节点处的位移和旋转自由度指定局部坐标系。
0.0,0.0,0.0,0.0,0.0,1.0
*boundary
ends,1,2
ends,4,4
ends,6,6
1,3

*step,nlgeom
static preload for internal pressure
*static
1.0,1.0
** 初始时间增量、步骤的时间段、允许的最小时间增量
*monitor,node=5040, dof=3
*dload
cylinder,p,0.0
*end step

*step,nlgeom
*buckle,eigensolver=lanczos
20,
*cload
top,3,-4.16667e-3
bottom,3,4.16667e-3
*output,field
*node output
u,
*node file,global=yes
u,
** 输出全模型所有节点的位移数据.fil
*end step