竹材横向断裂的物理模型与能量吸收机制:纤维束的断裂与抽拔

采用细观力学方法,研究竹材在横弯断裂过程中竹纤维束断裂与抽拔这2种损伤模式的能量吸收机制,并实际计算基本组织开裂、界面分层、竹纤维束断裂、竹纤维束抽拔4种损伤模式对竹材横弯断裂的增韧贡献。结果表明:1)不同组织结构在损伤演化过程中会因不同的能耗而具有不同的增韧贡献,在这4种导致竹材优良强韧性能的主要结构因素中,单位面积上纤维束拔出功对断裂功的贡献最大,其次是纤维束断裂;2)通过对试件的断裂总耗能试验值与按照4种损伤模型计算的耗能理论值进行比较,二者结果很接近,表明本文对竹材不同组织结构在横弯失效中的力学功能所建立的物理模型基本正确。

The Physical Model and Energy Absorbing Mechanism of Bamboo Transverse Fracture: The Fracture and Pulling-Out of fiber Bundles

In this paper,the moso-mechanics method was applied to study the energy absorbing mechanism of the fracture pattern and pulling-out pattern of bamboo fiber during process of bamboo transverse bending fracture. The toughness contributed by the cracking pattern of ground tissue,the layering pattern of interface,the fracture pattern and pulling-out pattern of fiber was calculated actually. The results indicated that: 1) different organization structures contributed different toughness to the evolution of damage because of different energy wastage and among the four main structure factors that lead to the excellent toughness property of bamboo,the pulling-out of fiber contributed most and the fracture of fiber second. 2) the comparison between the test value of the total energy wastage of fracture and the calculated theory value of the total energy wastage of the four damage patterns showed that the two values were very close. It indicated that the physical model founded for the mechanics functions of different organization structures in the process of transverse bending damage was right.