Fracture properties of green wood formed within the forks of hazel (Corylus avellana L.)

Interlocked grain and density patterns in Bagassa guianensis: changes with ontogeny and mechanical consequences for trees

“…In the second case, there may be small variations in the grain angle in the radial plane (wavy grain), increasing grain angle in the tangential plane from pith to bark (spiral grain), or periodic changes in the orientation of the fibres from the Z to S helix in the tangential plane (interlocked grain) (IG) (Hejnowicz and Romberger 1979;Krawczyszyn and Romberger 1979;Włoch et al 2009;Cabrolier 2009). The latter conformation is observable in numerous temperate and tropical tree species (Hernandez and Almeida 2003;Thinley et al 2005;Slater and Ennos 2015;Özden et al 2017). According to Kribs (1950, cited by Hernandez andAlmeida (2003)), 75% of the 258 tropical trees they analysed showed IG.…”

Mechanical properties of the most common European woods: a literature review

“…It is important to underline that not all the parameters were available in each document at the same time. For example, in the book section with ID18 [4] and for articles with ID3 [11], 8 [16], and 12 [20] the type of fracture parameters provided was not comparable or transformable into KIC by means of further equations. For articles with ID11 [19] and ID17 [25] the value of toughness (G f ) was found in place of fracture toughness (K IC ).…”

Examining Strain Propagation in the Lateral and Codominant Branch Attachment Using Digital Image Correlation

“…It appears this area limits the spread of strain during loading, just as it limits the spread of decay after branch shedding or breakage. It is likely that the complex anatomy and cross laminated grain pattern described by Shigo (1985), along with increased density and reduced S2 microfibril angle in the region (Lichtenegger et al 1999;Jungnikl et al 2009;Dahle and Grabosky 2009;Slater and Ennos 2013;Slater et al 2014;Özden et al 2017) have evolved to aid the tree in responding to the increased strain found during static loading.…”

“…Ductile materials are characterized by a materials ability to yield or stretch under loading at room temperature while brittle materials fail without any noticeable change in rate of elongation, or plastic deformation (Beer et al 2009). All things considered, the wood was about five times stronger in the branch attachment region than in surrounding tissue, likely due to higher density and lower microfibril angle (Slater and Ennos 2013;Slater et al 2014;Özden et al 2017). Beer et al (2009) note that the strength of a material is related to the strength of the elements that make up that material, and bound by its weakest element.…”

“…Breaking strength is typically measured as the maximum bending stress (σ) and is a function of applied bending load over resistance of the wood (Niklas 1992;Dahle and Grabosky 2009;Özden et al 2017). Resistance is determined using the moment of inertia (I), a function of the geometric shape (Beer et al 2001).…”