Flat Ring Flexure Test for Full-Culm Bamboo

The development of a new simple test method suitable for assessing the tension strength perpendicular to the fibres (Mode I) of a bamboo culm – the flat ring flexure test – is presented. The proposed test places a short section of bamboo culm in through-cross section flexure, causing circumferential stresses at failure. The modulus of rupture at the failed section is a measure of the transverse tensile strength of the culm. The test is compression-based (indeed, in the field it can be run using free weights rather than a test machine) and uses a simple apparatus and specimen. The full culm specimen is symmetric and requires very little preparation. The study first investigated test parameters affecting results, thereby arriving at an appropriate and repeatable standard test method. The resulting test method is documented in a format consistent with ISO 22157.