Comparison between three-point and four-point flexural tests to determine wood strength of Eucalyptus specimens

Maderas: ciencia y tecnologia

Brancheriau, Loïc¹  Hein, Paulo Ricardo Gherardi² 

[1] Univ Montpellier, Montpellier, France;Universidade Federal de Lavras, Lavras, Brazil

关键词: Acoustic vibration;    density;    Eucalyptus grandis;    static bending test;    stiffness;    strength.;   

DOI  :  10.4067/S0718-221X2018005003401

学科分类：农业科学（综合）

来源: Universidad del Bio-Bio

【 摘 要 】

Comparison between flexural wood strength values obtained from three-point and four-point bending tests in wood were only reported in few previous works, but remains unclear. Thus, the aim of this study was to determine the relationship between wood strength (MOR) obtained by 4-point and 3-point bending tests in Eucalyptus. Two or three specimens were cut from the same scantling (thus considered as twin) and submitted to flexural vibration tests. Then 190 wood specimens were tested by 4-point bending tests and 138 twin specimens were submitted to 3-point bending tests. Wood strength determined from 3-point bending test presented significantly higher mean value (76,8 MPa) than that from 4-point bending test (73 MPa). A linear regression for converting MOR from 3-point to 4-point bending test was proposed for these Eucalyptus specimens: MOR4p = 0,889 × MOR3p + 5,14 in MPa (R²=0,74). The correlation of MOR in 3-point bending with density was higher (R²=0,57) than in 4-point bending (R²=0,45). The correlations between dynamic elastic moduli and moduli of rupture were similar (circa R²=0,57 for MOR3p and R²=0,65 for MOR4p).

【 授权许可】

CC BY-NC