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Wood Science and Technology

, Volume 49, Issue 2, pp 345–357 | Cite as

The biomechanics of bamboo: investigating the role of the nodes

  • David TaylorEmail author
  • Billy Kinane
  • Ciara Sweeney
  • Darragh Sweetnam
  • Peter O’Reilly
  • Kai Duan
Original

Abstract

The stem of the bamboo plant consists of a hollow, tubular culm with periodic nodes, characterised by an internal diaphragm and an external ridge. Bamboo is a highly anisotropic material having a strong fibre orientation, but in the vicinity of the nodes, the fibres diverge from their longitudinal orientations. Previous researchers have claimed that the nodes have a biomechanical function, preventing failure by making the tube stiffer and stronger. To investigate this claim, tensile and bending tests were carried out on material samples and intact culms, both with and without nodes, to investigate culm stiffness and strength. Crack propagation tests were also carried out to determine the effect of nodes on fracture toughness. The results suggest that far from being a point of strength, the node may be a point of weakness when loaded in tension. Material in the node has a significantly lower tensile strength; in bending tests on intact culm lengths, failure occurs when the stress on the tensile side is exactly equal to the node’s tensile strength. Failure occurs by longitudinal splitting: it is proposed that this may be initiated by cracks forming in the nodes. The spacing of nodes is too large to affect the stiffness and strength of the tube as a whole and also greater than the critical crack length for brittle fracture. Thus, the diaphragm and ridge structure of the node can be explained as an attempt to reinforce a biologically essential feature which would otherwise be a point of weakness.

Keywords

Fracture Toughness Wind Loading Strain Energy Release Transverse Fracture Longitudinal Orientation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

We are grateful to Martin McNulty of Bamboo Suppliers of Ireland and to Brendan Sayers of the National Botanic Gardens, Glasnevin, Dublin, for supplying bamboo culms and helpful advice.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • David Taylor
    • 1
    Email author
  • Billy Kinane
    • 1
  • Ciara Sweeney
    • 1
  • Darragh Sweetnam
    • 1
  • Peter O’Reilly
    • 1
  • Kai Duan
    • 2
  1. 1.Trinity Centre for BioengineeringTrinity College DublinDublinIreland
  2. 2.Central Queensland UniversityRockhamptonAustralia

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