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林业科学 ›› 2008, Vol. 44 ›› Issue (5): 122-127.doi: 10.11707/j.1001-7488.20080523

• 论文 • 上一篇    下一篇

竹材的层间断裂性质

邵卓平   

  1. (安徽农业大学林学院 合肥230036)
  • 收稿日期:2007-03-05 修回日期:1900-01-01 出版日期:2008-05-25 发布日期:2015-04-22

Interlaminar Fracture Properties of Biomaterials Bamboo

Shao Zhuoping   

  1. (College of Forestry,Anhui Agricultural University Hefei 230036)
  • Received:2007-03-05 Revised:1900-01-01 Online:2008-05-25 Published:2015-04-22

摘要:

研究毛竹材的张开型和剪切型层间断裂行为,并基于能量原理,采用双悬臂梁和端部切口弯曲梁试样测定毛竹材顺纹向的Ⅰ型和Ⅱ型层间断裂韧性G-IC、G-IIC。结果表明:1) 竹材的Ⅰ和Ⅱ型层间断裂韧性是材料固有的属性,分别表征毛竹材对张开型裂纹和剪切型裂纹在层间扩展时的阻力;2)Ⅰ型裂纹扩展区域沿轴向具有光滑纤维与平整基体的特征,表明竹材基本组织强度及竹纤维/基本组织体间的界面强度较弱;Ⅱ型裂纹扩展区域中基体出现锯齿形受剪切变形的特征,表明基本组织在断裂前产生较大的剪切变形,故后者较前者吸收更多的断裂能(G-IIC≈25G-IC)。从整个断口形貌来看,裂纹扩展是在基体间和纤维/基体的界面上进行的,均为自相似断裂且无纤维桥联现象。

关键词: 竹材, 层间断裂韧性, Ⅰ型, Ⅱ型

Abstract:

The opining and shear interlaminar fracture behaviors of meso bamboo have been studied in this paper. Based on the energy concept,double cantilever beam(BCD)sample and end notched flexure (ENF)sample were applied to measure the model Ⅰ and model Ⅱ interlaminar fracture toughness of meso bamboo. The results show that: model Ⅰ and model Ⅱ fracture toughness of bamboo parallel to grain are basic properties of bamboo,which is the resistance of the opining and shearing cracks extend. The spread area of the crack of model Ⅰ shows the characteristic of smooth fiber and flat matrix. These manifest that the strength of the basictissue and interface strength of fiber/basic tissue is relatively weak. The spread area of the crack of model Ⅱ shows the characteristic of hackle shear deformation. These manifest that the basictissue brings the relatively big shear deformation before rupture. So the latter absorbs more fracture energies than the former. Judged by the whole morphologies of rupture surface,the cracking was carried on among basictissue and through the interface of fiber/tissue.Both of them are selfscaling fracture and with no fiberbridging.

Key words: bamboo, interlaminar fracture toughness, model Ⅰ, model Ⅱ