Evalution of Interlaminar Fracture Strength by Moire Interferometry

莫尔干涉法评价层间断裂强度

基本信息

批准号：
05650085
负责人：
ARAKAWA Kazuo
金额：
$ 1.41万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05650085/
关键词：
Composite Materials Fracture CFRP Interlaminar Fracture DCB Specimen Crack Opening Displacement Fracture Toughness Moire Interferometry 破壊靭性

项目摘要

Moire interferometry was utilized to study mode I interlaminar fracture in double cantilever beam (DCB) specimens of unidirectional carbon fiber/epoxy composites. The crack opening displacement (COD) was experimentally determined in the vicinity of the crack tip to evaluate the distortion at the beam root of the specimen. The beam root distortion was found to make an important contribution to increasing the value of COD.The effect of the beam root distortion on the evaluation of fracture toughness (G_I) value was also examined.An improved analytical model was introduced to study COD,G_I, and compliance (C) as a function of the material stiffness (lambda) ahead of the crack front. The COD solution was derived and compared with the COD profiles near the crack tip measured by moire interferometry. Results showed that the COD solution can predict all the important qualitative features of the measured COD profiles ; also, the quantitative agreement at the loading point was very good. It was found that lambda plays an important role in evaluating the values of COD,C and G_I.To study interlaminar deformation in DCB specimens of carbon fiber/epoxy composites, the values of COD determined by moire interferometry was compared with the analytical model. Estimations were made on the interlaminar tensile modulus and strain distribution ahead of the crack front. The results showed that the size of strain distribution was dependent on both the modulus and thickness of the specimens. Also there existed a specific correlation between the modulus and strain at the crack tip.

Moire干涉法用于研究模式I I层间骨折在单向碳纤维/环氧复合材料的双悬臂束（DCB）标本中。在裂纹尖端附近确定裂纹开口位移（COD），以评估样品束根部的失真。还发现了光束根部失真对增加COD的价值做出了重要贡献。还检查了光束根部失真对裂缝韧性评估（G_I）值评估的影响。将改进的分析模型引入了研究COD，G_I和合规性（C）作为材料刚度（Lambda）的功能。得出了COD溶液，并将其与Moire干涉测量法测量的裂纹尖端附近的COD剖面进行了比较。结果表明，COD解决方案可以预测测得的COD轮廓的所有重要定性特征。同样，加载点的定量协议非常好。发现Lambda在评估COD，C和G_I的值中起着重要作用。研究碳纤维/环氧复合材料的DCB样本中的层间变形，将Moire干涉测定法确定的COD值与分析模型进行了比较。对裂纹前沿前的层间拉伸模量和应变分布进行了估计。结果表明，应变分布的大小取决于样品的模量和厚度。在裂纹尖端处的模量和应变之间也存在特定的相关性。