Bending properties of a macroalga: Adaptation of Peirce's cantilever test for in situ measurements of Laminaria digitata (Laminariaceae)

Am J Bot. 2014 Jun 1;101(6):1050-1055. doi: 10.3732/ajb.1400163. Epub 2014 Jun 6.

Abstract

• Premise of the study: The mechanical properties of a plant are key variables governing the interaction between the plant and its environment. Thus, measuring variables such as the flexural rigidity (bending) of a plant element is necessary to understand and predict the plant-flow interaction. However, plant elements such as macrophyte blades can be relatively thin and flexible, thus difficult to characterize. Different adaptations of the classical 3-point bending tests can also affect the interpretation of the flexural rigidity of an element. A simple, robust, method is newly applied to a biomaterial and validated here as an alternative to measure flexural rigidity of thin, flexible plant elements.• Methods: Based on a bending test procedure developed for the textile industry, an apparatus for in-situ measurements was developed and compared with other normalized methods, then used in a field test on the blade of a marine macroalga (Laminaria digitata) to assess its suitability to measure the bending modulus of a biomaterial.• Key results: Results of the presented method on selected surrogate materials agree with a normalized cantilever method (ISO 9073-7:1998) and 3-point bending test (ISO 178:2010). Values determined for the bending moduli for blades of L. digitaria were in the typical range for algal material. The range of validity of the method is discussed.• Conclusion: By validating this method with existing norms, this study suggests a better approach to measure bending properties of different biomaterials in the field compared with more traditional bending tests and opens new possibilities.

Keywords: Laminaria digitata; Laminariaceae; bending modulus; bending test; biomaterial; biomechanics; flexural rigidity; macroalga.

MeSH terms

  • Biomechanical Phenomena
  • Elastic Modulus
  • Kelp*
  • Laminaria*
  • Materials Testing
  • Stress, Mechanical*