Failure of Elliptical Tubes with Different Long–Short Axis Ratios under Cyclic Bending in Different Directions
Although elliptical tubes are stronger and more stable than circular tubes, few studies have fully considered the behavior of elliptical tubes under cyclic bending loads. This study experimentally investigated the response and failure of SUS304 stainless steel elliptical tubes with four different ra...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-11-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/13/11/1891 |
| _version_ | 1797458395648753664 |
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| author | Min-Cheng Yu Wen-Fung Pan |
| author_facet | Min-Cheng Yu Wen-Fung Pan |
| author_sort | Min-Cheng Yu |
| collection | DOAJ |
| description | Although elliptical tubes are stronger and more stable than circular tubes, few studies have fully considered the behavior of elliptical tubes under cyclic bending loads. This study experimentally investigated the response and failure of SUS304 stainless steel elliptical tubes with four different ratios of long and short axes (1.5, 2.0, 2.5, and 3.0) under cyclic bending along four different orientation angles (0°, 30°, 60°, and 90°). The wall thickness was 0.7 mm, and cyclic bending was applied until buckling failure occurred. The moment–curvature curves exhibited cyclic hardening, and stable loops were formed for all long–short axis ratios and orientation angles. Increasing the long–short axis ratio slightly decreased the peak bending moment while increasing the orientation angle increased the peak bending moment. For a given orientation angle, the curves relating the short-axis variation (i.e., change in length divided by the original length of the short axis) and curvature demonstrated symmetry, serrations, and a growth pattern as the number of cycles increased regardless of the long–short axis ratio. At long–short axis ratios of 2.0, 2.5, and 3.0, these curves even exhibited a butterfly-like trend. Increasing the long–short axis ratio increased the short-axis variation, while increasing the orientation angle decreased the short-axis variation. Regarding the curves relating the curvature and number of cycles required to initiate buckling, for each orientation angle, the four long–short axis ratios corresponded to four straight lines when plotted on double-logarithmic co-ordinates. Based on the experimental results, empirical equations are proposed to describe the above relationships. The empirical equations were applied to predicting experimental data and showed close agreement. |
| first_indexed | 2024-03-09T16:37:28Z |
| format | Article |
| id | doaj.art-b464533acc644ebcad575a4ff7423f08 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-09T16:37:28Z |
| publishDate | 2023-11-01 |
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| series | Metals |
| spelling | doaj.art-b464533acc644ebcad575a4ff7423f082023-11-24T14:55:59ZengMDPI AGMetals2075-47012023-11-011311189110.3390/met13111891Failure of Elliptical Tubes with Different Long–Short Axis Ratios under Cyclic Bending in Different DirectionsMin-Cheng Yu0Wen-Fung Pan1Department of Engineering Science, National Cheng Kung University, Tainan 701, TaiwanDepartment of Engineering Science, National Cheng Kung University, Tainan 701, TaiwanAlthough elliptical tubes are stronger and more stable than circular tubes, few studies have fully considered the behavior of elliptical tubes under cyclic bending loads. This study experimentally investigated the response and failure of SUS304 stainless steel elliptical tubes with four different ratios of long and short axes (1.5, 2.0, 2.5, and 3.0) under cyclic bending along four different orientation angles (0°, 30°, 60°, and 90°). The wall thickness was 0.7 mm, and cyclic bending was applied until buckling failure occurred. The moment–curvature curves exhibited cyclic hardening, and stable loops were formed for all long–short axis ratios and orientation angles. Increasing the long–short axis ratio slightly decreased the peak bending moment while increasing the orientation angle increased the peak bending moment. For a given orientation angle, the curves relating the short-axis variation (i.e., change in length divided by the original length of the short axis) and curvature demonstrated symmetry, serrations, and a growth pattern as the number of cycles increased regardless of the long–short axis ratio. At long–short axis ratios of 2.0, 2.5, and 3.0, these curves even exhibited a butterfly-like trend. Increasing the long–short axis ratio increased the short-axis variation, while increasing the orientation angle decreased the short-axis variation. Regarding the curves relating the curvature and number of cycles required to initiate buckling, for each orientation angle, the four long–short axis ratios corresponded to four straight lines when plotted on double-logarithmic co-ordinates. Based on the experimental results, empirical equations are proposed to describe the above relationships. The empirical equations were applied to predicting experimental data and showed close agreement.https://www.mdpi.com/2075-4701/13/11/1891SUS304 stainless steel elliptical tubeslong–short axis ratiosorientation anglesmomentcurvatureshort–axis variation |
| spellingShingle | Min-Cheng Yu Wen-Fung Pan Failure of Elliptical Tubes with Different Long–Short Axis Ratios under Cyclic Bending in Different Directions Metals SUS304 stainless steel elliptical tubes long–short axis ratios orientation angles moment curvature short–axis variation |
| title | Failure of Elliptical Tubes with Different Long–Short Axis Ratios under Cyclic Bending in Different Directions |
| title_full | Failure of Elliptical Tubes with Different Long–Short Axis Ratios under Cyclic Bending in Different Directions |
| title_fullStr | Failure of Elliptical Tubes with Different Long–Short Axis Ratios under Cyclic Bending in Different Directions |
| title_full_unstemmed | Failure of Elliptical Tubes with Different Long–Short Axis Ratios under Cyclic Bending in Different Directions |
| title_short | Failure of Elliptical Tubes with Different Long–Short Axis Ratios under Cyclic Bending in Different Directions |
| title_sort | failure of elliptical tubes with different long short axis ratios under cyclic bending in different directions |
| topic | SUS304 stainless steel elliptical tubes long–short axis ratios orientation angles moment curvature short–axis variation |
| url | https://www.mdpi.com/2075-4701/13/11/1891 |
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