Bamboo Bundle Corrugated Laminated Composites (BCLC). Part I. Three-Dimensional Stability in Response to Corrugating Effect

A novel bamboo bundle laminated composite with a corrugated structure, denoted BCLC, was developed. The objective of this work was to investigate how the three-dimensional shrinkage and swelling properties are affected by the shape of the composites. Three types of stacking sequences were designed and their shrinkage and swelling performances were compared. A shape parameter, K, was used to quantify the corrugated effect on the shrinkage or swelling in three directions. The dimensional stability of the BCLC was significantly different among the three directions of the composites, and it was affected by the stacking sequence of the bamboo bundles. Shrinkage ratio, swelling ratio, and drying coefficient were significantly greater in the thickness direction compared with those in the length or width directions. Corrugated effect in response to width and thickness direction was positive, vs. negative to length. The absolute value of shape parameter was largest in the length direction and smallest in the thickness direction, KL>KW>KT. The corrugated effect of BCLC was more pronounced with swelling than with shrinkage. The correlations of porosity ratio (PR) vs. apparent density (AD) was determined as r=-0.930, and that of WA vs. AD was determined as r=-0.940. The correlation of water absorption (WA) vs. PR was positive (r=0.997). The synergistic effect of stacking sequence accounted for 11.3%, 9.2%, and 0.6% of the total correlation above, respectively.