Abstract

The industrial utilization of natural bamboo has been plagued by cracking that are closely related to the relationship between the moisture content (MC) and drying shrinkage. To reveal the cracking mechanism, three relationships between environmental factors and drying rate (DR), MC and shrinkage strain, strain variation and cracking were investigated during the air seasoning (AS) of the 6-meter-long bamboo in free state. The DR decreased significantly affected by hygroscopicity, and a model considering hygroscopicity and environmental factors was proposed for estimating the DR. Natural bamboos were prone to cracking between 42% and 12% MC. The top cracking was earlier and more than other parts, which is caused by initial lower MC and absence of end diaphragm. There were significant differences in shrinkage strain between different tissues and sites. This work reveals the drying characteristics, the law of strain variation, and cracking mechanism in bamboo AS process, which is vital to the prevention and control of drying defects.

摘要

天然竹的工业利用一直受到与水分含量（MC）和干燥收缩关系密切相关的开裂的困扰。为揭示开裂机制，研究了 6 米长竹子在自由状态下风干（AS）过程中环境因素与干燥速率（DR）、MC 和收缩应变、应变变化和开裂的三种关系。DR受吸湿性影响显着降低，提出了一种考虑吸湿性和环境因素的模型来估算DR。天然竹子在 42% 到 12% MC 之间容易开裂。顶部开裂较早且多于其他部位，这是由于初始较低的MC和没有端膜片造成的。不同组织和部位的收缩应变存在显着差异。这项工作揭示了竹子AS工艺的干燥特性、应变变化规律和开裂机制，这对于预防和控制干燥缺陷至关重要。