WANG Shu-juan, XIE Bao-yuan. Modeling analysis of the bending modulus of elasticity for branches in the period of dormancy[J]. Journal of Beijing Forestry University, 2014, 36(6): 130-134. DOI: 10.13332/j.cnki.jbfu.2014.06.024
Citation:
WANG Shu-juan, XIE Bao-yuan. Modeling analysis of the bending modulus of elasticity for branches in the period of dormancy[J]. Journal of Beijing Forestry University, 2014, 36(6): 130-134. DOI: 10.13332/j.cnki.jbfu.2014.06.024
WANG Shu-juan, XIE Bao-yuan. Modeling analysis of the bending modulus of elasticity for branches in the period of dormancy[J]. Journal of Beijing Forestry University, 2014, 36(6): 130-134. DOI: 10.13332/j.cnki.jbfu.2014.06.024
Citation:
WANG Shu-juan, XIE Bao-yuan. Modeling analysis of the bending modulus of elasticity for branches in the period of dormancy[J]. Journal of Beijing Forestry University, 2014, 36(6): 130-134. DOI: 10.13332/j.cnki.jbfu.2014.06.024
1 Key Laboratory of Soil and Water Conservation & Desertification Combating of Ministry of Education, Beijing Forestry University, 100083, P. R. China;
This paper analyzes the effects of branch age, moisture content and density of fresh branches of
evergreen and deciduous trees during the period of dormancy on the modulus of elasticity(MOE) by
adding the dummy variable into regression model. These branches were from the seven species (five
deciduous trees and 2 evergreen trees in December 2012, including 40-year-old Pinus tabulaeformis, 30-
year-old Platycladus orientalis, 12-year-old Ailanthus altissima, 20-year-old Robinia pseudoacacia, 30-
year-old Koelreuteria paniculata, 40-year-old Euonymus maackii, and 35-year-old Acer truncatum. Totally
176 fresh twigs as research samples were collected in the Experimental Forest Farm of Beijing Forestry
University. The twig age was firstly measured by using the branch sequence method, and then confirmed
by counting the annual rings when test specimen was produced in the laboratory. Moisture content was
measured in accordance with the national standard method for determination of the moisture content of
wood GB/ T 1931-2009 (ISO 3130:1975 MOD). Density was obtained in compliance with the national
standard method for determination of the density of wood GB/ T 1933-2009, in which the volume of
branch was measured by the water drainage method. MOE measurement was in compliance with the
national standard method for determination of the MOE in static bending of wood GB/ T 1936.2-2009.
The MOE of the fresh twigs was obtained by three-point bending test. The EViews7.0 was used for the
least-square regression analysis of the mechanical performance parameters of the 176 fresh dormant twigs,
and the results indicated that there was significant correlation between MOE and the age of fresh twig in
the initial phase of dormancy . The MOE of fresh twigs decreased in curved line with the increase of age.
The effects of moisture content and density of fresh twigs on MOE are not significant. The tree species
have marked effect on the change of MOE.
DownLoad: