Investigating the Underlying Effect of Thermal Modification on Shrinkage Behavior of Bamboo Culm by Experimental and Numerical Methods

Abstract

This study probes into the root cause of split in thermally modified bamboo culm by investigating the underlying effect of thermal contraction with respect to its orthotropic nature by experimental and numerical methods while concurrently monitoring the chemical variation of its structure by Fourier transformed infrared spectroscopy (FTIR). In first part of this study, a non-linear increase in dimensional and weight changes of small clear bamboo specimens were observed with increasing temperature. The dimensional changes in the radial and tangential directions significantly exceeded that in the longitudinal direction. From FTIR results, shrinkage effect between 150 °C to 200 °C was associated with weight loss engendered by reduction in weakly bound water and increase in desorption of water content while alteration of its mechanical properties was attributed to changes in cellulose, hemicellulose, and lignin. From results of finite element method (FEM), the graded variation in thermal expansion coefficient, which showed the formation of a narrowed region of strain concentration corresponding to longitudinal crack propagation, was associated with the inducement of internal forces, namely tensile and compressive forces, at specific regions along the culm length. The results of this study can be useful to achieve optimized durability in modified bamboo for construction.

Numerical modelling of the warping behaviour at the first layer-build plate interface in 3D-printed models produced via the fused deposition modelling process

“…The utilization of FEM software to investigate material behavior in the field of additive manufacturing provide numerous benefits namely by controlling and overcoming frequent defects encountered in 3D prints such as voids, over extrusion and layer separation. The effective strain criterion, 𝜀 which has been widely used to investigate failure mechanisms in various material types [17,18], was considered to assess the material deformation in the 3D-printed model.…”

Investigating the Effect of Smoke Treatment on Hygroscopic Characteristics of Bamboo by FTIR and Raman Spectroscopy

“…Environmental factors such as ultraviolet radiation, rain, and humidity are among the few abiotic factors which affect the durability and structural performance of bamboo. Besides, the hygroscopicity trait, which is the affinity of bamboo to absorb water content via its surface, significantly influences the premature fracture in bamboo materials due to nonuniform shrinkage and swelling [1]. One way to improve its durability limitations is via treatment modification such as natural drying which enhances its dimensional stability and its resistance to natural degradation [2][3][4].…”

“…The ratio of normalized heights of the absorption peaks of control and treated bamboo samples were found to be useful to assess changes due to treatment modification [20]. FTIR has also been used in various studies to assess the chemical change due to treatment modification in the surface of bamboo structure [1,6].…”