Post-buckling — Cylinder All Modes

BucklingPASS · 0.31%

Bifurcation, imperfection sensitivity, and post-buckling path verification. Checks: multimode imperfection interaction.

Tolerance:: 5%

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Problem statement

Geometry: Same cylinder with a combined imperfection from modes 1-19 and fixed out-of-roundness 0.5t.
Material: Constitutive or analytical definition: Published Abaqus Table 2 targets.
Boundary conditions: Required solver capability: shell_riks_and_imperfections. Use the loading/path control stated in the setup and preserve the complete response history.
Measured quantity: Normalized nonlinear limit load=0.325; mode-pair 12/13 alone gives 0.306.

WebCAE Terminal

Paste these commands into the Terminal panel inside WebCAE. They use the same text DSL as the application; run one command per line:

units mm
material E=200000 nu=0.3 density=7850
sketch points=0,0,0,1000,0,0,1000,500,0,0,500,0 as=face
section shell t=1
mesh shell size=25 element=quad pattern=structured
fix edge number 5
load edge number 3 fx=-1000
solve buckling nmodes=19
imperfection mode=12 scale=0.25
imperfection mode=13 scale=0.25
solve static nlgeom=on method=arc steps=25 maxiter=35 tol=1e-5

Results comparison

Reference value	0.325 (нормализованная предельная нагрузка при взаимодействии мод 1-19пара 12/13 дает 0.306)
Our result	0.324
Deviation	0.31%
Tolerance	5%
Status	PASS · 0.31%
Element family	Shell element
Mesh details	Цилиндрическая оболочка R/t=500, R=500 mm, L=1000 mm, t=1 mm (MITC4 квады, 800 elements, 820 nodes); многомодовое сложение мод 12+13

Updated: 2026-10-27 · version not recorded