MASS ESTIMATION OF PILED ROUND BARS THROUGH VIBRATION TESTS
Keywords:
additional mass, density, piled round bars, rubbe, sticker, vibration test, Young’s modulusAbstract
A simple method was developed to estimate the mass of each piled round bar using a vibration test. Specimens used in the tests were Japanese cedar (Cryptomeria japonica D. Don) round bars (diameter = 180 mm, length = 2000 mm) with a pith and a back split. Vibration tests were conducted, and the effect of sticker positions on the vibration test was investigated. The vibration tests were conducted for each piled round bar and the estimation accuracy of the vibration method with additional mass (VAM) was examined. By placing the round bar on the stickers, the resonance frequency of the longitudinal vibration was stable while that of the bending vibration decreased with the increase in the distance between the sticker and the specimen end and stabilized when this distance was greater than or equal to 0.2l (l:specimen length). When the round bars were piled with no stickers, the bending resonance frequency could not be identified and the VAM estimation accuracy of the longitudinal vibration depended on the specimens. The estimation accuracy of VAM for the longitudinal vibration of the piled round bars while using stickers made of wood and rubber was superior to that without stickers. The estimation accuracy of VAM for the bending vibration was sufficiently high. These results were attributed to the reduction of the vibration restraint by the stickers and the contact between adjacent round bars.
References
Aratake S, Arima T, Sakoda T (1994) Estimation of moisture content of lumber and logs using higher natural frequency of longitudinal vibrations. Mokuzai Gakkaishi 40:474-480.
Aratake S, Arima T, Sakoda T, Nakamura Y (1992) Estimation of Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) of lumber using higher natural frequency of log in pile of logs. Possibility of application for sugi scaffolding board. Mokuzai Gakkaishi 38:995-1001.
Kiribayashi M, Morita H, Fujimoto T (2016) Management of drying for decked logs by measurement of stress wave propagation times. Wood Ind 71:312-316.
Kishi K, Kojiro K, Akashi H, Adachi W, Fuchigami Y, Tabuchi A, Furuta Y (2019) Prediction of strength grades of lumbers by evaluating those of logs: Development of the simple and convenient prediction method as a case study of logs from areas in Kyoto Prefecture. Wood Ind 74(4): 140-145.
Kubojima Y, Kato H, Tonosaki M, Sonoda S (2016) Measuring young’s modulus of a wooden bar using flexural vibration without measuring its weight. BioRes 11:800- 810.
Kubojima Y, Sonoda S (2015) Measuring Young’s modulus of a wooden bar using longitudinal vibration without measuring its weight. Eur J Wood Wood Prod 73:399- 401.
Kubojima Y, Sonoda S, Kato H (2017a) Practical techniques for the vibration method with additional mass: effect of crossers’ position in longitudinal vibration. J Wood Sci 63:147-153.
Kubojima Y, Sonoda S, Kato H (2017b) Practical techniques for the vibration method with additional mass: effect of specimen moisture content. J Wood Sci 63:568-574.
Kubojima Y, Sonoda S, Kato H (2018a) Practical techniques for the vibration method with additional mass: bending vibration generated by tapping cross section. J Wood Sci 64:16-22.
Kubojima Y, Sonoda S, Kato H (2018b) Application of the vibration method with additional mass to timber guardrail beams. J Wood Sci 64:767-775.
Kubojima Y, Sonoda S, Kato H (2019) Use of cut specimen pieces in the vibration method with additional mass (VAM). J Wood Sci 65:30.
Kubojima Y, Sonoda S, Kato H (2020a) Mass of piled lumber estimated through vibration test. J Wood Sci 66:32.
Kubojima Y, Sonoda S, Kato H (2021) Measuring density and Young’s modulus of a log through the vibration test without measuring its weight. J Wood Sci 67:6.
Kubojima Y, Sonoda S, Kato H, Harada M (2020b) Effect of shear and rotatory inertia on the bending vibration method without weighing specimens. J Wood Sci 66:51.
Matsubara M, Aono A, Ise T, Kawamura S (2016) Study on identification method of line density of the elastic beam under unknown boundary conditions. Trans JSME 82(837): doi: 10.1299/transjsme.15-00669.
Matsubara M, Aono A, Kawamura S (2015) Experimental identification of structural properties of elastic beam with homogeneous and uniform cross section. Trans JSME 81(831). doi: 10.1299/transjsme.15-00279.
Nakayama Y (1968) Studies on the dynamic Young’s modulus of wooden beam (I) The dynamic Young’s modulus and the bending strength. Bull Kochi Univ For 2:17-32.
Skrinar M (2002) On elastic beams parameter identification using eigen frequencies changes and the method of added mass. Comput Mater Sci 25:207-217.
Sonoda S, Kubojima Y, Kato H (2016) Practical techniques for the vibration method with additional mass Part 2: Experimental study on the additional mass in longitudinal vibration test for timber measurement. CD-ROM Proc World Conference on Timber Engineering (WCTE 2016), August 22-25, 2016, Vienna, Austria.
Türker T, Bayraktar A (2008) Structural parameter identification of fixed end beams by inverse method using measured natural frequencies. Shock Vib 15:505-515.
Urabe T, Asano K, Hirota K, Katagiri Y (2017) A simple method for determining the strength of Sugi logs at the stacking stage. Abstracts of the 67th Annual Meeting of Japan Wood Research Society, March 17-19, 2017, Fukuoka, Japan, D18-P1-06.
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