Abstract:

Thin-walled tubes， commonly used structures in automobile lightweight and industrial production， have the advantages of lightweight and high strength. The study of the axial compression instability characteristics of thin-walled tubes is helpful for its application in optimizing structural design and safety. Therefore， a novel axial compression fold model of thin-walled tubes is proposed to describe the morphological characteristics and average compressive load of deformation folds for thin-walled tubes based on the energy method. The prediction accuracy of the new theoretical model and the plastic hinge model for the fold length and compressive average load is validated by experiments and finite element simulation. The results show that the fold length predicted by the new theoretical model is closer to the experimental and finite element results compared with the plastic hinge model， with the average prediction error reduced by 55.2%. The prediction accuracy for compressive average load is improved by 29.7% after the friction coefficient correction. When guiding engineering practice， a fold prediction model considering friction effect correction should be adopted.

Key words: fold prediction model, thin-walled circular tube, energy method, axial instability, compressive load