Poissons Ratio Laminated Bamboo Lumber

Winandy and david e.

Poissons ratio laminated bamboo lumber.

The bamboo culm and the low rigidity of the bamboo. The poisson s ratios are denoted by μlr μrl μlt μtl μrt and μtr. Poisson s ratio is a measure of the poisson effect that describes the expansion or contraction of a material in directions perpendicular to the direction of loading the value of poisson s ratio is the negative of the ratio of transverse strain to axial strain for small values of these changes is the amount of transversal expansion divided by the amount of axial compression. Poisson s ratios for common materials.

For example μlr is the poisson s ratio for. Dr 0 334 100 10 3 m 5 10 3 m 10 m 1 7 10 5 m 0 017 mm. With poisson s ratio for aluminum 0 334 the contraction can be calculated as. Given the anisotropic nature of the laminated material compression tests were performed on three groups of specimens.

In the engineering of elastic models wood is treated. Mechanical properties of wood david w. Kretschmann contents orthotropic nature of wood 4 1 elastic properties 4 2 modulus of elasticity 4 2 poisson s ratio 4 2 modulus of rigidity 4 3 strength properties 4 3 common properties 4 3 less common properties 4 24 vibration properties 4 25. The first letter of the subscript refers to direction of applied stress and the second letter to direction of lateral deformation.

To solve these problems modern industrial bamboo materials appeared in different forms such as glubam 1 2 parallel bamboo strand lumber pbsl 3 4 laminated bamboo lumber lbl 5 10 and so on. For most common materials the poisson s ratio is in the range 0 0 5. The poisson s ratio of laminated bamboo in off axis plane increased first and then decreased with the change of the off axis angle and reached the maximum when the off axis angle is 30. By studying the elastic modulus and poisson s ratio of laminated bamboo under different loading directions takeuchi et al.

Laminated bamboo is a natural composite material with cellulose fibers parenchyma cells and vascular bundles. The elasticity modulus and poisson ratio of laminated bamboo. Bamboo tubes can be disassembled into bamboo filament bundles by passing. The average poisson s ratio parallel to grain 0 and perpendicular to grain 90 are 0 31 and 0 06 respectively.

Wood is generally considered to be an anisotropic material. 19 proved laminated bamboo could be treated as orthotropic material. The mechanical characterization of this material includes not only the determination of its strength but also of its elastic constants.