Advertisement

Journal of Wood Science

, Volume 63, Issue 6, pp 568–574 | Cite as

Practical techniques for the vibration method with additional mass: effect of specimen moisture content

  • Yoshitaka Kubojima
  • Satomi Sonoda
  • Hideo Kato
Original article

Abstract

This work examines the effect of moisture content on the accuracy of nondestructively and simply estimating weight, density, and Young’s modulus by a vibration test without measuring specimen weight. The resonance frequencies with and without concentrated mass were measured by longitudinal vibration and bending vibration tests. The wet specimens whose initial moisture contents were 93–134% were dried at 20 °C and 65% relative humidity, and their weight, density, and Young’s modulus were estimated. The accuracy of the estimation was affected by the increase in the resonance frequency, caused by the drying process, during the vibration tests. The resonance frequency without the concentrated mass should, therefore, be measured after obtaining the resonance frequency with the concentrated mass. The accuracy of the estimation in the bending vibration test was higher than that in the longitudinal vibration test. This tendency can be explained by the error in the measurement of resonance frequencies with and without the concentrated mass.

Keywords

Bending vibration Longitudinal vibration Moisture content Vibration method with additional mass Wood 

Notes

Acknowledgements

This study was supported by JSPS KAKENHI Grant number JP15K07522.

References

  1. 1.
    Chai GB, Low KH (1993) On the natural frequencies of beams carrying a concentrated mass. J Sound Vib 160:161–166CrossRefGoogle Scholar
  2. 2.
    Low KH, Lim TM, Chai GB (1993) Experimental and analytical investigations of vibration frequencies for center-loaded beams. Comput Struct 48:1157–1162CrossRefGoogle Scholar
  3. 3.
    Low KH (1994) An equivalent-center method for quick frequency analysis of beams carrying a concentrated mass. Comput Struct 50:409–419CrossRefGoogle Scholar
  4. 4.
    Skrinar M, Umek A (1994) The influence of an added mass to a change of eigenfrequencies. J Mech Eng 11:443–450Google Scholar
  5. 5.
    Skrinar M (2002) On elastic beams parameter identification using eigenfrequencies changes and the method of added mass. Comput Mater Sci 25:207–217CrossRefGoogle Scholar
  6. 6.
    Kubojima Y, Tonosaki M, Yoshihara H (2003) Effect of the additional mass applied at an end of a wooden beam on its flexural vibrational properties. Wood Ind 58:370–372Google Scholar
  7. 7.
    Kubojima Y, Tonosaki M, Yoshihara H (2005) Effect of additional mass on Young’s modulus of a wooden beam. J Test Eval 33:278–282Google Scholar
  8. 8.
    Türker T, Bayraktar A (2008) Structural parameter identification of fixed end beams by inverse method using measured natural frequencies. Shock Vib 15:505–515CrossRefGoogle Scholar
  9. 9.
    Kubojima Y, Suzuki Y, Tonosaki M (2014) Effect of additional mass on the apparent Young’s modulus of a wooden bar by longitudinal vibration. BioRes 9:5088–5098CrossRefGoogle Scholar
  10. 10.
    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 73:399–401CrossRefGoogle Scholar
  11. 11.
    Matsubara M, Aono A, Kawamura S (2015) Experimental identification of structural properties of elastic beam with homogeneous and uniform cross section. Trans JSME. doi: 10.1299/transjsme.15-00279 Google Scholar
  12. 12.
    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 11:800–810Google Scholar
  13. 13.
    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. doi: 10.1299/transjsme.15-00669 Google Scholar
  14. 14.
    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. In: CD-ROM Proceedings of the World conference on timber engineering (WCTE 2016)Google Scholar
  15. 15.
    Kubojima Y, Sonoda S, Kato H (2017) Practical techniques for the vibration method with additional mass: effect of crossers’ position in longitudinal vibration. J Wood Sci 63:147–153CrossRefGoogle Scholar

Copyright information

© The Japan Wood Research Society 2017

Authors and Affiliations

  1. 1.Forestry and Forest Products Research InstituteTsukubaJapan
  2. 2.Toyama Prefectural Agricultural, Forestry and Fisheries Research CenterImizuJapan

Personalised recommendations