The LaMCoS team studies softwood mechanical behaviour with the mean of an image correlation method. This optical technique allows obtaining much data from simple experiments. To begin with, tests on macroscopic specimens (several annual rings) have been used to quantify the orthotropic mean elastic, behaviour in the transverse plane. Shear tests analysed on only some annual rings (mesoscopic scale) have clearly shown the important heterogeneity of softwood, many times stiffer in late wood than in early wood. This anisotropy and heterogeneity in the transverse plane have an influence on fracture phenomenon even in longitudinal structures. Some 4 points bending experiments on longitudinal spruce beams shown different fractures modes and limits depending on the local angle of the fibres in the beam.
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