Compressive Strength Parallel to the Grain in Relation to Moisture Content in Calamus simplicifolius Cane

This research aimed to investigate the compressive fracture behavior and the compressive strength parallel to the grain in relation to moisture contents (MC) below and above the fiber saturation point (FSP) in Calamus simplicifolius cane. FSP of the rattan was investigated using a dynamic vapor sorption (DVS) apparatus, and the fracture behaviors of compression parallel to grain were analyzed by three-dimensional X-ray microcomputed tomography. The study indicated that the value of FSP derived from the DVS method was 25 percent. The average compressive strength parallel to the grain was found to be 39 MPa at 3 percent MC, 30 MPa at 10 percent MC, 17 MPa at 12 percent MC, 12 MPa at 27 percent MC, and 10 MPa at 45 percent MC. The strains of the yield and densification stage were prolonged with increasing MC, whereas the stress in the linear elastic stage decreased with increasing MC. The cracks of the rattan core and the deflection angle at higher MC were larger than that of low MC. Below the FSP, the compressive failure of the rattan showed a shear band oriented around 45° to the loading axis, and the surface was rough. Above the FSP, the rattan samples showed brooming failure. The interface among fiber bundles was delaminated and the fiber surface in the failure area was smooth. The fracture toughness of the rattan was higher than that of wood, which suggests that the rattan might be more suitable for modeling and curved materials.