|
CSME 2024/06
Volume 45 No.3
:
201-208
|
|
Response and Failure of Elliptical Tubes With Different Long/Short Axis Ratios Under Cyclic Bending
Min-Cheng Yua and We n-Fung Pana
aDepartment of Engineering Science, National Cheng Kung University, Tainan, Taiwan 70101, ROC.
|
Abstract:
This paper investigates the response and failure of SUS304 stainless steel elliptical tubes with four different long/short axis ratios (1.5, 2.0, 2.5, and 3.0) under cyclic bending. The wall thickness is 0.7 mm for all elliptical tubes, and cyclic bending loads are applied until buckling failure occurs. The experimental moment-curvature relationships exhibit cyclic hardening and form stable loops for all long/short axis ratios. An increase in the long/short axis ratio results in a slight decrease in the peak bending moment. The experimental relationships between short axis variation and curvature (where short axis variation represents the change in the length of the short axis divided by the original length of the short axis) demonstrate symmetry, serrations, and a growth pattern as cycles progress, regardless of the long/short axis ratio. Interestingly, when long/short axis ratios are equal to 2.0, 2.5, and 3.0, the relationships even exhibit butterfly-like trends. Moreover, a larger long/short axis ratio corresponds to a greater short axis variation. Regarding the curvature-number of cycles required to initiate buckling relationships, it can be observed that the four long/short axis ratios correspond to four straight lines when plotted on double logarithmic coordinates. Lastly, this study proposes theoretical equations to describe the aforementioned relationships. The theoretical analysis is compared with experimental data, revealing a close alignment between the two approaches. This indicates that the theory can reasonably describe the experimental results.
|
|
Keywords: SUS304 stainless steel elliptical tubes, long/short axis ratios, moment-curvature relationships, short axis variation-curvature relationships, cyclic bending, buckling failure.
|
|
|
*Corresponding author; e-mail:
|
©
2024
CSME , ISSN 0257-9731
|