基于VIC-3D技术的重组竹I型断裂参数确定方法

Determination of mode-I fracture parameters of parallel strand bamboo based on VIC-3D technology

重组竹是原竹经工业化制造而成的一种高强复合材料,近年来被用于建筑结构。由于重组竹内部存在许多微裂纹,断裂破坏是重组竹构件的主要失效模式。本文基于线弹性断裂理论和Irwin能量原理,采用VIC-3D全场变形测量技术确定裂纹扩展长度,通过重组竹楔形试件断裂试验,研究重组竹I型裂纹的断裂性能,给出重组竹的断裂韧度和R曲线。试验表明:VIC-3D全场变形测量技术可准确确定裂纹尖端,避免了等效柔度法的复杂运算。该方法的结构与等效柔度法高度一致,是研究重组竹断裂性能的一种有效测量手段。

Fabricated via industrial process using raw bamboo, Parallel strand bamboo （PSB） is a high strength composite which has been used in building constructions in recent years. Microvoids are inevitably left in PSB composite owing to the dimensional inconsistence of bamboo fibers; hence fracture due to mocrovids coalescence and expanding maybe a major failure mode of PSB components. This paper amid at studying on the Mode I fracture properties based on LEFM theory and Iwrin＇ s energy theory. Wedge splitting test was employed as test method. The length of crack expending was determined by three dimensional virtual image correlation （VIC-3D） global-field deformation acquisition system. Fracture toughness of PSB and R-curves were obtained. The results showed that the VIC-3D global-field acquisition system can precisely determine the crack tip and the complicated calculation for crack length determination may be avoided. Good agreement may be achieved between the result of this method and compliance approach, which indicated that the proposed method in this study is efficient.