The Influence of Diameter-to-Thickness Ratios on the Response and Collapse of Sharp-Notched Circular Tubes under Cyclic Bending

Abstract

This paper discusses an experimental investigation of the behavior of sharp-notched circular tubes subjected to cyclic bending. The sharp-notched circular tubes of 304 stainless steel with three different diameter-to-thickness ratios (D o / t) were tested under symmetric curvature-controlled cyclic bending. It has been shown that the moment-curvature curves exhibited the loops with cyclic hardening and gradually becoming steady after a few cycles for all tested tubes. The ovalization-curvature curves revealed unsymmetric, ratcheting and increasing behavior with the number of cycles. In addition, five almost parallel lines corresponding to five different notch depths for each D o / t ratio were found from the experimental relationship between the cyclic controlled curvature and the number of cycles necessary to produce buckling on a log-log scale. Finally, an empirical relationship was proposed so it could be used for simulating the aforementioned relationship. By comparing with the experimental finding, the derived empirical relationship was in good agreement with the experimental data.

The Failure of Local Sharp-Dented 6061-T6 Aluminum Alloy Tubes With Different Diameter-to-Thickness Ratios Under Cyclic Bending

“…Later, Chang et al [19] studied the buckling failure of 301 stainless steel smooth tubes with different D o /t ratios subjected to cyclic bending. In 2012, Lee et al [20] started to investigate the influence of the D o /t ratio on the response and failure of sharpnotched 304 stainless tubes subjected to cyclic bending. The type of the sharp notch was in Fig.1 and three different D o /t ratios were 16.25, 21.20 and 24.46.…”