激光辐照对竹材抗劈力的影响

Effect of Laser Irradiation on Cleavage Strength of Bamboo

竹材内应力大、横向连接弱是造成竹材容易劈裂、影响其使用的重要原因。激光处理热效率高,可调整基体结构,细化晶粒,消除内应力。为研究激光对竹材抗劈力的影响,通过激光辐照毛竹材,分析激光功率、辐照时间、试件厚度及竹材表皮保留情况对毛竹抗劈力的影响,结果表明:毛竹抗劈力较低,小于2.5 N/mm;毛竹抗劈力随激光功率的增大而增大,激光功率为2 100 mW时较未处理毛竹的抗劈力提高13.5%;激光辐照处理30 s时较未处理毛竹抗劈力提高13.5%;随辐照时间延长、试件厚度增加,毛竹抗劈力减小;保留竹青有利于提高竹材的抗劈力;激光辐照对竹黄侧抗劈力的提高效果最好,可使其提高20%。

The high internal stress and weak connection along transverse of bamboo is a big cause of its easily splitting.Laser irradiation is an effective method for thermal treatment,which is supposed to eliminate internal tress in bamboo by refining crystalline grain.In this study,the effects of laser power,irradiation time,specimen thickness and bamboo surface retention on cleavage strength of Phyllostachys pubescens were analyzed.The results showed that cleavage strength of Phyllostachys pubescens is low than 2.5 N/mm;The cleavage strength increased with increasing laser power,which increased by 13.5%when laser power is 2100 m W.While the cleavage strength declined with prolonging laser irradiation time and increasing thickness.Green skin reservation is beneficial to improve cleavage strength,while laser irradiation is positive for yellow skin with the cleavage strength increased by 20%on yellow skin of bamboo.