Compressive Failure Mechanism of Structural Bamboo Scrimber

Abstract

Bamboo scrimber is one of the most popular engineering bamboo composites, owing to its excellent physical and mechanical properties. In order to investigate the influence of grain direction on the compression properties and failure mechanism of bamboo scrimber, the longitudinal, radial and tangential directions were selected. The results showed that the compressive load–displacement curves of bamboo scrimber in the longitudinal, tangential and radial directions contained elastic, yield and failure stages. The compressive strength and elastic modulus of the bamboo scrimber in the longitudinal direction were greater than those in the radial and tangential directions, and there were no significant differences between the radial and tangential specimens. The micro-fracture morphology shows that the parenchyma cells underwent brittle shear failure in all three directions, while the fiber failure of the longitudinal compressive specimens consisted of ductile fracture, and the tangential and radial compressive specimens exhibited brittle fracture. This is one of the reasons that the deformation of the specimens under longitudinal compression was greater than those under tangential and radial compression. The main failure mode of bamboo scrimber under longitudinal and radial compression was shear failure, and the main failure mode under tangential compression was interlayer separation failure. The reason for this difference was that during longitudinal and radial compression, the maximum strain occurred at the diagonal of the specimen, while during tangential compression, the maximum strain occurred at the bonding interface. This study can provide benefits for the rational design and safe application of bamboo scrimber in practical engineering.

A Review of Basic Mechanical Properties of Bamboo Scrimber Based on Small-Scale Specimens

“…The results show that as the fiber orientation tends to be horizontal, the compressive strength of BS decreases, and the fiber buckling is less and less, mostly glue cracking and splitting between fibers. The longitudinal, tangential and radial compression tests show that the failure of the specimens caused by three loading directions is strength failure, and there are main cracks along the diagonal, the load-displacement curves in three grain directions include three stages of elasticity, yield and failure [51,56]. In the microscopic observation of the failure mode, it is shown that the fiber fracture of the longitudinal compression specimen is ductile, and the fiber fracture of the tangential and radial compression specimens is brittle, which is the reason why the deformation and strength of the longitudinal compression are greater than those of the tangential and radial compression [56].…”

“…The longitudinal, tangential and radial compression tests show that the failure of the specimens caused by three loading directions is strength failure, and there are main cracks along the diagonal, the load-displacement curves in three grain directions include three stages of elasticity, yield and failure [51,56]. In the microscopic observation of the failure mode, it is shown that the fiber fracture of the longitudinal compression specimen is ductile, and the fiber fracture of the tangential and radial compression specimens is brittle, which is the reason why the deformation and strength of the longitudinal compression are greater than those of the tangential and radial compression [56]. However, when the temperature rises to a certain extent, due to the degradation of the resin, the ductile failure of BS parallel to grain will be transformed into brittleness, and the crushing failure occurs in the transverse direction [57] In the composite test of BS and steel tube, it is found that the steel tube significantly increases the compressive strength and axial strain of BS, and restrains the lateral deformation of BS well.…”

Preparation of PO43−-Intercalated Calcium–Aluminum Hydrotalcites via Coprecipitation Method and Its Flame-Retardant Effect on Bamboo Scrimber

“…Bamboo scrimber is a new type of composite bamboo lumber, which is made from bamboo culms crushed into loose reticular fibrous bundles [ 1 , 2 ]. In recent years, bamboo scrimber has been widely used in construction and decoration materials due to its excellent mechanical properties and environmental friendliness [ 3 ].…”