End effect on determining shear modulus of timber beams in torsion tests

Gharavi, N.; Zhang, H.; Xie, Y.; He, T.

Abstract

The end effect plays an important role in determining where the rotation measuring gauges should be located in a torsion test. A thorough review on the impact of end effect in a torsion test has been conducted, followed by an experimental validation. A close-ranged photogrammetric method using binocular stereo vision technique was employed in this study. The results have indicated that the end effect has a great impact on a region of 1.5 times the cross-sectional depth of the beam from the supports. Therefore, the distance between the gauges and the supports as specified in BS EN 408:2010+A1:2012 for the torsion test setup is not sufficient for the beams with slender cross-sections. This research has also indicated that it is more appropriate to use the depth of the beam as the referencing dimension to specify this required minimum distance.

• Journal Article Type: Article
• Acceptance Date: Dec 27, 2017
• Online Publication Date: Jan 4, 2018
• Publication Date: Mar 10, 2018
• Deposit Date: Jan 26, 2018
• Publicly Available Date: Jan 5, 2019
• Journal: Construction and Building Materials
• Print ISSN: 0950-0618
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 164
• Pages: 442-450
• DOI: https://doi.org/10.1016/j.conbuildmat.2017.12.191
• Keywords: Saint-Venant’s end effect, Structural-size torsion test, Timber beam’s shear modulus, Photogrammetry, binocular stereo vision
• Public URL: http://researchrepository.napier.ac.uk/Output/1031826
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0950061817325965?via%3Dihub
• Contract Date: Feb 16, 2018