Measurement of rolling shear modulus of Cross Laminated Timber: Exploratory study using downscaled specimens under variable span bending tests
The purpose of this study was to measure the rolling shear modulus of Cross Laminated Timber (CLT), which was achieved by conducting 3-point bending tests with variable span using downscaled sandwich specimens. Two types of sandwich specimens were employed: steel-wood-steel (SWS) and wood-wood-wood (WWW). Experimental results from SWS specimens were verified with those predicted from WWW ones through the shear analogy method. Effects of span-to-depth ratio (l/h) and growth ring orientation on rolling shear modulus (GRT) were also examined. It was found that the average deflection of WWW specimens tested at l/h of 6.5 could be well predicted using the shear analogy method based on true elasticity of modulus (Em) and GRT of the cross layer measured using SWS specimens under variable span tests. The results also showed that the cross layer of `in-between' growth ring orientation could gain the higher rolling shear modulus than that of flat sawn or quarter sawn one.
Duration-of-load and size effects on the rolling shear strength of cross laminated timber
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Comparison of torsion tube and Iosipescu in-plane shear test results for a carbon fibre-reinforced epoxy composite
Abstract Measurement of the shear stiffness and strength of fibre-reinforced composite materials has proved to be more difficult than that of other properties, and significant discrepancies in results have been reported in the literature. Two tests have been used recently, torsion and side-notched (Iosipescu), that appear to have some advantages. This paper gives the results of comparison tests run on AS4/3501-6 carbon fibre-reinforced epoxy composite. In general the results were found to agree quite well, with average initial modulus values differing by 1%, failure stress by 5% and failure strain by 31%.