权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Development of Static and Fatigue Strength Characterization System for Composite Interface using In-situ Observation

利用原位观测开发复合材料界面静态和疲劳强度表征系统

基本信息

批准号：
11555032
负责人：
HOJO Masaki
金额：
$ 4.1万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555032/
关键词：
Composite materials Inter facial strength Model composites Mesoscopic structure In-situ observation Static strength Fatigue strength Numerical analysis

项目摘要

Macroscopic fracture properties of fiber reinforced composite materials depend on the properties of mesoscopic components such as fiber, matrix, fiber/matrix interface and their spacial distribution. Then, the direct measurements of the fracture behavior of these mesoscopic components are important for the understanding of the fracture process in mesoscopic scale. In the present study, two types of model composites were used to evaluate the inter facial strength of glass fiber/epoxy composites. One is microcomposite, in which one central fiber was pulled out from six surrounding fibers was The other is couple fiber shear specimen, in which a pair of fibers was pulled away. The latter was specially designed for in-situ observation. Tests were carried out under static and fatigue loadings using low-load capacity fatigue testing machine attached to scanning electron microscope. Two and three dimensional finite element analyses were carried out to find out the mechanism and criterion of th … More e inter facial fracture.The results are summarized as follows :(1) In microcomposite tests, the fracture surface indicated the transition point of stable opening mode crack propagation to unstable shear mode crack propagation. This can be correlated to the maximum pullout load in the experiments. This condition can be expressed by the constant intensity of stress singularity without respect to the fiber diameter and the resin impregnated length.(2) In couple fiber shear tests, in-situ observation showed stable crack growth before final unstable fracture. The three-dimensional finite element analysis indicated that the controlling mode of the fracture was mode I without respect to the crack length. The transition of stable to unstable crack growth was correlated to the minimum values of the mode I stress intensity factor with the crack length. .(3) Couple fiber tests were carried out with fibers of different fiber diameters. The comparison of the results indicated that the above criterion was valid without respect to the fiber diameter.(4) The tests were also carried out under fatigue loading with automated controlling and data acquisition systems. Less

纤维增强复合材料的宏观断裂性能取决于纤维、基体、纤维/基体界面等细观组分的性能及其空间分布。因此，直接测量这些细观组分的断裂行为对于理解细观尺度下的断裂过程具有重要意义。在本研究中，两种类型的模型复合材料被用来评估玻璃纤维/环氧树脂复合材料的界面强度。一种是微复合材料试样，其中一根中心纤维从周围六根纤维中拔出，另一种是双纤维剪切试样，其中一对纤维被拔出。后者是专门为现场观测而设计的。试验在静态和疲劳载荷下进行，使用低负荷能力疲劳试验机连接到扫描电子显微镜。通过二维和三维有限元分析，探讨了裂纹扩展的机理和判据 ...更多信息结果表明：（1）在微复合材料试验中，断裂面指示了稳定张开型裂纹扩展向不稳定剪切型裂纹扩展的转变点。这可以与实验中的最大拔出载荷相关联。这一条件可以用应力奇异性强度不变来表示，而与纤维直径和树脂浸渍长度无关。(2)在双纤维剪切试验中，原位观察表明裂纹在最终不稳定断裂之前稳定扩展。三维有限元分析表明，断裂的控制模式是模式I与裂纹长度无关。稳定到不稳定的裂纹扩展的过渡与模式I的应力强度因子与裂纹长度的最小值。. (3)用不同纤维直径的纤维进行偶联纤维测试。结果比较表明，上述判据与纤维直径无关。(4)试验还在疲劳载荷下用自动控制和数据采集系统进行。少