Nonlinear mode interaction in equal-leg angle struts susceptible to cellular buckling

Area of Science:

• Structural Engineering
• Mechanical Engineering
• Materials Science

Background:

• Thin-walled structures are susceptible to complex buckling behaviors under axial compression.
• Understanding interactive buckling is crucial for safe and efficient structural design.
• Existing models may not fully capture the nonlinear interactions in angle struts.

Purpose of the Study:

• To develop and validate a variational model for the interactive buckling of thin-walled equal-leg angle struts.
• To investigate the novel phenomenon of progressive cellular buckling (snaking).
• To analyze the nonlinear interaction between different buckling modes.

Main Methods:

• Utilized a variational model combined with the Rayleigh-Ritz method.
• Employed continuous displacement functions to derive equilibrium equations.
• Solved equations using numerical continuation.
• Conducted physical experiments on cold-formed steel specimens.

Main Results:

• The model accurately predicts interactive buckling behavior.
• Revealed progressive cellular buckling (snaking) for the first time.
• Identified highly unstable behavior resulting from mode interaction.
• Experimental results showed good agreement with the model's predictions.

Conclusions:

• The developed variational model is effective for analyzing angle strut buckling.
• Progressive cellular buckling is a significant and previously unrecognized instability mode.
• The findings enhance the understanding of thin-walled structure behavior under compression.
• Experimental validation confirms the model's predictive capabilities.