Classification of buckling modes in stiffened functionally graded composite tubes subject to bending

Luan Trinh, Paul Weaver

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Bamboo poles, and other one-dimensional thin-walled structures are usually loaded under compression, which may also be subject to bending arising from eccentric loading. Many of these structures contain diaphragms or circumferential stiffeners to prevent cross-sectional distortions and so enhance overall load-carrying response. Such hierarchical structures can compartmentalize buckling to local regions in addition to withstanding global buckling phenomena. Predicting the buckling mode shapes of such structures for a range of geometric parameters is challenging due to the interaction of these global and local modes. Abaqus finite element software is used to model thousands of circular hollow tubes with random geometric parameters such that the ratios of radius to periodic length range from 1/3-1/7, the ratio of wall thickness to radius varies from 1/4-1/10. The material used in this study is a type of bamboo, where the Young's and shear moduli are point-wise orthotropic and gradually increase in magnitude in the radial direction. Under eccentric loads with varying eccentricity, the structures can buckle into a global mode or local modes within an internode, i.e. periodic unit. Moreover, the local modes may contain only one wave or multiple waves in the circumferential direction. As expected, numerical results show that the global mode is more likely to occur in small and thick tubes, whereas the local modes are observed in larger tubes with a smaller number of circumferential waves present in thicker walls. Also, greater eccentricity pushes the local mode domains towards smaller tubes. An efficient classification method is developed herein to identify the domains of each mode shape in terms of radius, wall thickness and eccentricity. Based on linear discriminant analysis, explicit boundary surfaces for the three domains are defined for the obtained data, which can help designers in predicting the mode shapes of tubular structures under axial bending.

Original languageEnglish
Title of host publication36th Technical Conference of the American Society for Composites 2021
Subtitle of host publicationComposites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021
EditorsOzden Ochoa
PublisherDEStech Publications
Pages356-366
Number of pages11
ISBN (Electronic)9781713837596
Publication statusPublished - 2021
Event36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021 - College Station, Virtual, United States
Duration: 20 Sep 202122 Sep 2021

Publication series

Name36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021
Volume1

Conference

Conference36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021
Country/TerritoryUnited States
CityCollege Station, Virtual
Period20/09/2122/09/21

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