Mode Coarsening or Fracture: Energy Transfer Mechanisms in Dynamic Buckling of Rods

Area of Science:

• Solid Mechanics
• Nonlinear Dynamics
• Materials Science

Background:

• Thin elastic rods are susceptible to buckling under axial impact.
• Understanding postbuckling behavior is crucial for structural integrity.
• Existing models may not fully capture complex dynamic responses.

Purpose of the Study:

• Investigate the postbuckling behavior of thin elastic rods under axial impact.
• Identify and characterize novel postbuckling mechanisms.
• Develop a predictive model for mode coarsening.

Main Methods:

• Hybrid approach combining experimental, theoretical, and simulation techniques.
• Derivation of a purely geometric force relaxation model.
• Validation using molecular dynamics (MD) simulations.

Main Results:

• Discovery of a new postbuckling mechanism: mode coarsening.
• Mode coarsening involves energy transfer from higher to lower wave numbers.
• Fracture dissipates strain energy, halting mode coarsening.

Conclusions:

• The derived model accurately captures mode coarsening.
• Findings offer insights into impact-induced buckling and fracture.
• Scalable models enable safer engineering design for structures prone to buckling.