Abstract
As a natural graded material, bamboo has gradually increasing elastic modulus along the radial direction from the inner to the outer skin. Accurate measurement of the modulus distribution plays an important role in bamboo-based structural design. However, it is difficult to characterise this modulus distribution by using conventional testing approaches on bamboo slices. A more effective method was developed in this study for the inverse identification of gradually varying material properties. The method is based on the digital image correlation and finite element model updating techniques. The radial distribution of the elastic modulus of bamboo was obtained through only one four-point bending test. The inversely identified modulus distribution was verified through uniaxial tensile tests on sliced bamboo strips and microscopic observation of the volume fraction distribution of its vascular bundle. The results showed that the elastic modulus of the bamboo material decreased from the outer skin (20 GPa) to the inner skin (2 GPa), which is in good consistence with the tensile test results on sliced specimens.
Funding source: National Natural Science Foundation of China
Award Identifier / Grant number: 11602022
Award Identifier / Grant number: 11727801
Award Identifier / Grant number: 11772053
Award Identifier / Grant number: 11872115
Award Identifier / Grant number: U1837602
Acknowledgments
The authors wish to acknowledge Prof. Zhengjun Sun from the International Centre for Bamboo and Rattan for his help in providing the bamboo samples for this study.
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: This study was supported by the National Natural Science Foundation of China (grant nos. 11872115, U1837602, 11727801, 11772053 and 11602022).
Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
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