Stiffened panel buckling load estimates vary by element type and method
Element-dependent buckling loads of stiffened panels under cantilevered shear
Computational Engineering, Finance, and Science
Summary
Predicting when certain structural panels buckle under stress depends on the details of the computer model used. The authors compare different finite element models and find that stiffness and load predictions differ based on how each model handles rotations and stresses. Some models closely match more complete calculations, while others can overestimate or underestimate the load by significant amounts. This work helps identify which modeling choices give more reliable buckling load predictions under shear stress.
What this means in practice
- •For structural engineers: Choose finite element models that closely match complete second variation forms for more accurate stiffened panel buckling load predictions under cantilevered shear.
- •For design simulation teams: Optimize mesh and element type selections in simulation software to balance accuracy and performance in modeling stiffened panel buckling.
Authors
Lifeng Wang, Zhongli Qiu, Xuanhao Cheng, Run Du, Wenming Cheng, Min Xie, Xiong Rao
Abstract
The linearized buckling load of a stiffened panel depends on the stress stiffness its shell element assembles. We read it from exported operators against three truncations of one second variation. The classic pass of ANSYS SHELL181 carries a rotation-rotation block pairing the drilling freedom with the bending rotations and its perturbation pass does not; removing the block recovers the perturbation load factor to 0.02%. SHELL281 carries block and couplings in both passes. Abaqus S4 matches the critical mode of the complete second variation to 1.0000 on the translations and its load factor to 1.7%, against 17% and 34% for the other two forms. On an optimized panel under cantilevered shear a 20-node continuum lies 3% to 6% above that form, S4 and SHELL281, 11% and 23% below both SHELL181 passes and 25% above Abaqus S8R, at the finest meshes. On a conventionally stiffened panel the SHELL181 passes stand 1.0% and 3.5% above the complete form, 9% and 21% at half the rib pitch; under a shear flow, on cylinders, open beams and under axial compression the three forms coincide and no pass parts by more than 0.3%.