Effect of the specimen configuration on the accuracy in measuring the shear modulus of western hemlock by torsional vibr
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Effect of the specimen configuration on the accuracy in measuring the shear modulus of western hemlock by torsional vibration test Hiroshi Yoshihara1 · Makoto Maruta2 Received: 27 January 2020 / Accepted: 7 October 2020 / Published online: 16 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The shear moduli of solid wood in longitudinal–tangential and longitudinal–radial planes were obtained by conducting a torsional vibration test and subsequent numerical analyses on western hemlock specimens by fixing the thickness as 10 mm and varying the width and length in the ranges of 20–80 mm and 100–400 mm, respectively. In the numerical analyses, the shear modulus in the tangential–radial planes was varied, and its effect was also examined as well as those of the width and length of the model. The results obtained indicated that the effect of the shear modulus in the tangential–radial plane was enhanced as the width increased and the length decreased. However, the shear modulus in the wider plane of the specimen could be obtained accurately by reducing the effect of the shear modulus in the tangential– radial plane when appropriate ranges of the width and length were determined. From the numerical and experimental results, the shear moduli in the longitudinal–tangential and longitudinal–tangential planes were accurately obtained when the width was in the range of 20–40 mm and the length was in the range of 250–400 mm.
Introduction To obtain the shear modulus of solid wood and wood-based materials, vibration tests are possible because the shear modulus can be determined nondestructively (Brancheriau and Baillerres 2002). The flexural vibration (FV) tests have been frequently conducted because they are suitable for measuring the shear modulus of the specimen with a bar shape in which the flexural mode vibrations are easily induced. To this effect, various successful applications of the FV tests have been * Hiroshi Yoshihara [email protected]‑u.ac.jp 1
Faculty of Science and Engineering, Shimane University, Nishikawazu‑cho 1060, Matsue, Shimane 690‑8504, Japan
2
Faculty of Science and Technology, Shizuoka Institute of Science and Technology, Toyosawa 2200‑2, Fukuroi, Shizuoka 437‑8555, Japan
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Vol.:(0123456789)
1480
Wood Science and Technology (2020) 54:1479–1496
reviewed by Brancheriau and Baillerres (2002). In addition, the use of bar-shaped materials in structures such as beams and columns is common increasing the need for conducting the FV tests. However, in the FV test, both the Young’s modulus and the shear modulus are to be obtained, and therefore, multiple resonance frequencies for the FV modes should be assessed in order to distinguish between the Young’s modulus and shear modulus. This implies that the Young’s modulus and the shear modulus data are not independent entities and the accuracy of determining the Young’s modulus affects the accuracy of the shear modulus. Additionally, to accurately obtain the shear modulus by conducting the FV test, it is necessary to
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