Research on the post-buckling strength of screw composite thin plate with large deflection

Abstract

The effect of membrane stress on axial strength of screw composite thin plate is addressed in this paper. In order to study the post-buckling behavior of the screw composite thin plate, the instability mechanism was analyzed theoretically based on the large deflection theory, experimental and numerical investigation were described in this paper. Considering the shear deformation and screw restraint, the calculation model of ultimate stress for the screw composite thin plate was established, and the analytical formula of the ultimate stress of the screw composite thin plate with four simply supported edges and two opposite sides under uniform compression was derived. The composite thin plate obtained from cold-formed steel back-to-back built-up short columns assembled by self-drilling screws, commonly used in practical projects, was used as the test models. Then, the experimental and numerical results were compared with theoretical results mentioned above to modify the proposed formula. According to the comparison, the modified coefficient φ was derived by nonlinear regression, and the modified ultimate stresses were in good agreement with the experimental and numerical results, the results were reasonable and reliable.