Buckling of high-strength steel cylinders under cyclic bending in the inelastic range

Abstract

The present paper examines the structural behavior of high-strength elongated steel cylinders, referred to as tubes or pipes, subjected to strong cyclic bending, through a rigorous finite element simulation. The cylinder exhibits cross-sectional distortion, in the form of ovalization, combined with excessive plastic deformations. Those deformations, under repeated loading, may lead to instability in the form of local buckling (wrinkling) and, eventually, failure of the loaded member. The study focuses on relatively-thick-walled cylindrical members, which exhibit local buckling in the plastic range of the steel material, with the use of advanced nonlinear finite element models able to describe both geometrical and material nonlinearities. A cyclic plasticity model that adopts the "Bounding Surface" concept is employed, calibrated through special-purpose material testing, and implemented within ABAQUS, using a user-subroutine. The numerical model is validated by comparison with available experimental data on tubular members made of high-strength steel. Finally, a parametric numerical study is conducted, aimed at determining the effects of geometrical imperfections of the cylinder on its plastic buckling performance. Copyright © 2013 by ASME.