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

纤维增强材料的宏观断裂取决于纤维，基质，基质界面的特性。 /环氧复合材料是微复合材料，其中一种中央纤维从六个侧面的纤维中拉出，另一个是在静态和疲劳载荷下使用载荷能力疲劳测试机在扫描电子显微镜上的静态和疲劳载荷。元素是按照以下方式总结的机理和标准：（1）在微熟悉的测试中，断裂表面表明稳定的打开模式裂纹的过渡点向不稳定的剪切模式裂纹传播。在实验中的最大拉力载荷。骨折。直径。结果表明上述标准无需没有纤维直径而没有。