STUDY ON THE EVALUATION METHOD OF HTE FRACTURE TOUGHNESS OF CFRP LAMINATES.

CFRP层合板高温断裂韧性评价方法的研究。

• 批准号: 63550090
• 负责人: KIKUCHI Masanori
• 金额: $ 1.15万
• 依托单位: Faculty of Science & Technology, Science University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63550090/
• 关键词: Fracture Toughness; CFRP Laminates; Mode I, Mode II; Mixed Mode; Composite Material; モ-ドII; 破壊条件; 混合モード; G_<IC>; G_<IIC>; 異方性体

The method to evlauate the fracture toughness of CFRP laminates is studied. in this research. The linear fracture mechanics can be used with good accuracy to predict the stress field At the crack tip of CFRP specimen. Then the some numerical methods, for example, finite element method and boundary element method, are available in this study. At first, the fracture experiment and numerical analysis are carried out and the mode I fracture toughness, GIC, is estimated. A new method combining the experiment and analysis is proposed. By this method, it is not necessary to measure the crack length during the experiment. Second, a method to evaluate the fracture toughness of mode II is proposed. In this method, it is necessary to estimate the contact area between upper and lower crack surfaces and the contact force distributions between them. A new BEM code is made for this purpose, and it enables to estimate the contact area and force distributions with good accuracy. By introducing this method in the estimation scheme, the fracture toughness of mode II can be estimated easily. Finally the mixed mode specimen is proposed in this research and the state of mixed mode is checked by the three dimensional finite element analysis. Three dimensional J integral is evaluated and it is decomposed into three modes of stress intensity factors, KI, KII, and KIII. It is shown that though mixed mode fracture occurred in this type of specimen, the fracture mode is mode I dominant. It is concluded that another method to include mode I, II and III should be considered. This problem no attracts a wide attention and a new project between Japan, United States, and Europe is being planned. I will continue to effort to establish a new method to estimate the mixed mode fracture toughness of CFRP laminates as a member of this new project.

研究了CFRP层合板断裂韧性的评价方法。in this research研究.用线性断裂力学方法可以较准确地预测CFRP试件裂纹尖端的应力场。在此基础上，本文采用了有限元法、边界元法等数值方法，并对这些方法进行了数值模拟。首先，进行了断裂试验和数值分析，估算了Ⅰ型断裂韧度GIC。提出了一种实验与分析相结合的新方法。该方法在实验过程中不需要测量裂纹长度。其次，提出了一种估算Ⅱ型断裂韧性的方法。在该方法中，需要估计上下裂纹面之间的接触面积以及它们之间的接触力分布。为此，编制了一个新的边界元程序，该程序能够准确地估计接触面积和力的分布。通过在估算方案中引入该方法，可以很容易地估算出Ⅱ型断裂韧度。最后提出了复合模态试件，并通过三维有限元分析对复合模态状态进行了验证。计算了三维J积分，并将其分解为KI、KII和KIII三种模式的应力强度因子。结果表明，虽然在这种类型的试样发生混合模式断裂，断裂模式是模式I占主导地位。得出的结论是，应考虑采用另一种方法，将模式一、二和三包括在内。这个问题没有引起广泛的关注，日本，美国和欧洲正在计划一个新的项目。本人将继续致力于建立一种新的方法来估算CFRP层合板的复合型断裂韧性，作为这个新项目的一员。

项目成果

Kazuro Kageyama,Kiyoshi Ueno and Masanori Kikuchi: "FATIGUE DAMAGE ANALYSIS OF NOTCHED CARBON/EPOXY LAMINATES BY THERMOELASTIC EMISSION AND THREE DIMENSIONAL FINITE ELEMENT METHOD." Proc.of 7th Int.Cong.on Composite Meterials.(ICCM 7),Beijing. 144-149 (19

Kazuro Kageyama、Kiyoshi Ueno 和 Masanori Kikuchi：“通过热弹性发射和三维有限元法对缺口碳/环氧树脂层压板进行疲劳损伤分析。”

Kazuro Kageyama, Noboru Yanagisawa and Masanori Kikuchi: "CHARACTERIZATION OF MODE II INTERLAMINAR CRACK GROWTH BASED ON ANALYTICAL COMPLIANCE METHOD." Proc. of 7th Int. Conf. on Composite Materials (ICCM 7) pp.363-367, 1989.

Kazuro Kageyama、Noboru Yanagisawa 和 Masanori Kikuchi：“基于分析合规方法的 II 型层间裂纹扩展特征。”

Masanori Kikuchi,Takayuki Kobayashi and Kazuro Kageyama: "MODE I INTERLAMINAR FRACTURE OF UNIDIRECTIONALLY REINFORCED CARBON?NYLON LAMINATES." Proceedings of 6th Int.Congress on Experimental Mechanics.1101-1106 (1988)

Masanori Kikuchi、Takayuki Kobayashi 和 Kazuro Kageyama：“单向增强碳尼龙层压板的 I 型层间断裂。”

Masanori Kikuchi,Kazuro Kageyama and Kiyoshi Ueno: "FATIGUE DAMAGE ANALYSIS OF NOTCHED CARBON?EPOXY LAMINATES BY THERMOELASTIC EMISSION AND THREE DIMENISONAL FINITE ELEMENT METHOD." Proceedings of 7th Int.Conf.on Composite Material.(ICCM7)、Beijing,. 144-1

Masanori Kikuchi、Kazuro Kageyama 和 Kiyoshi Ueno：“通过热弹性发射和三维有限元方法对缺口碳进行疲劳损伤分析。”第七届复合材料国际会议论文集（ICCM7），北京，144-。 1

Kazuro Kageyama,Noboru Yanagisawa and Masanori Kikuchi: "CHARACTERIZATION OF MODE II INTERLAMINAR CRACK GROWTH BASED ON ANALYTICAL COMPLIANCE METHOD." Proc.of 7th Int.Conf.on Composite Materials.(ICCM 7),Beijing. 363-367 (1989)

Kazuro Kageyama、Noboru Yanagisawa 和 Masanori Kikuchi：“基于分析合规方法的模式 II 层间裂纹扩展的表征。”