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General Assessment of Fatigue Reliability of Composite Material Structures

复合材料结构疲劳可靠性的一般评估

基本信息

批准号：
63420038
负责人：
KIMPARA Isao
金额：
$ 11.14万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63420038/
关键词：
Composite material structures Fatigue reliability Fatigue damage S-N diagram Stiffness reduction curve AE method Acousto-ultrasonic method Evaluation of defects SーN線図 AE特性層間き裂進展特性 AE

项目摘要

The three-years research program has been completed aiming at general assessment of fatigue reliability of composite material structures. The main results are summarized as follows :1. A testing system was developed based on a servopulser with two-column loading frames installed with repeated loading fixture under variable load ratio in circulation environment chamber which can optionally be connected with AE measuring and analyzing instruments in order to make a systematic assessment of fatigue damage of composite material structures.2. A systematic three-point flexural fatigue test was carried out on glass, aramid and glass/aramid hybrid FRP laminates for marine use in air and in water. The standard fatigue design data was obtained and the damage fatigue mechanism was characterized in terms of S-N diagrams and stiffness reduction curves.3. The acousto-ultrasonic method and the AE method were applied to evaluate the effects of progressive fatigue damage. It was shown that the fatigue damage was successfully characterized in terms of apparent change in attenuation of through-thickness ultrasonic wave propagation and some AE parameters such as hits and amplitudes.4. An attempt was made to characterize the AE properties of CFRP laminates containing several types of artificial defects such as void and delamination. The effect of defects on strength of CFRP laminates was examined by means of monotonous and cyclic three-point flexural loading. Some correlations between AE parameters and defects were established in terms of AE hits, amplitude and AE hits during load hold.5. The enough data has not yet been obtained on systematic fatigue tests on standarddefect specimens and FRP joint structures in salt water. The effect of load ratio on durability of composite material structures has also not yet been clarified. The general fatigue design data including these characterizations will be presented in the near future.

为期三年的研究计划已完成，旨在对复合材料结构的疲劳可靠性进行总体评估。主要结果如下： 1．开发了一种基于伺服脉冲发生器的两柱加载框架，在循环环境室中安装了重复加载夹具，在可变载荷比下可选择性地连接AE测量和分析仪器，以对复合材料结构的疲劳损伤进行系统评估。 2．对船用玻璃、芳纶和玻璃/芳纶混合 FRP 层压板在空气和水中进行了系统的三点弯曲疲劳测试。获得了标准的疲劳设计数据，并用S-N图和刚度折减曲线表征了损伤疲劳机理。 3．采用声超声法和AE法评价渐进性疲劳损伤的影响。结果表明，通过超声波沿厚度方向传播的衰减明显变化以及声发射次数、振幅等声发射参数，成功地表征了疲劳损伤。 4．尝试表征含有多种类型人工缺陷（例如空隙和分层）的 CFRP 层压板的 AE 性能。通过单调循环三点弯曲载荷研究了缺陷对CFRP层合板强度的影响。 AE参数与缺陷之间的一些相关性根据AE命中率、振幅和负载保持期间的AE命中率建立了一些相关性。5．标准缺陷试件和玻璃钢节点结构在盐水中的系统疲劳试验尚未获得足够的数据。载荷比对复合材料结构耐久性的影响也尚未明确。包括这些特征的一般疲劳设计数据将在不久的将来提供。