![flexture test with three point loading flexture test with three point loading](https://i.ytimg.com/vi/YmGcaO33Kl4/maxresdefault.jpg)
(2002b) advises that the values obtained by one method cannot be directly compared with those of other methods and so the bending properties have to be converted before using them and correctly compared with others from different references. There are several standard procedures for performing bending tests in order to obtain flexural strength and flexural modulus. (1989) the fundamental differences are the location of the maximum bending moment and maximum axial fiber stresses: the maximum stress occurs directly below the loading nose in three-point loading, but is spread out over the area between the loading noses in the four-point system. These bending tests simulate tensile and compression stress on a wood specimen and its physical response behavior is monitored. In most cases 3-point bend and 4-point bend are suggested for prediction of flexural properties of the materials ( Kumar and Murthy 2012). According to Mujika (2006) mechanical properties, such as strength and stiffness, can be calculated using a range of test methods. Non-destructive tests are mostly based on propagation speed using acoustic or ultrasonic waves and acoustic spectral analysis in which dynamic elastic properties can be estimated.ĭestructive tests are based on the application of a force on the specimen until it fails: the stress to strain plot, the maximum force until failure and the distance displaced are recorded ( Kollmann and Côté 1968).
Mechanical properties of the materials can be obtained from destructive and non destructive testing. Keywords: Acoustic vibration, density, Eucalyptus grandis, static bending test, stiffness, strength. The correlations between dynamic elastic moduli and moduli of rupture were similar (circa R²=0,57 for MOR 3p and R²=0,65 for MOR 4p). The correlation of MOR in 3-point bending with density was higher (R²=0,57) than in 4-point bending (R²=0,45). A linear regression for converting MOR from 3-point to 4-point bending test was proposed for these Eucalyptus specimens: MOR 4p = 0,889 × MOR 3p + 5,14 in MPa (R²=0,74). 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). Then 190 wood specimens were tested by 4-point bending tests and 138 twin specimens were submitted to 3-point bending tests. Two or three specimens were cut from the same scantling (thus considered as twin) and submitted to flexural vibration tests. 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. Funding source: Conselho Nacional de Desenvolvimento Científico e Tecnológicoįunding source: Fundação de Amparo à PesquisaĪbstract: 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.