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。在这项研究中。线性断裂力学可以很好地预测CFRP试件裂纹尖端的应力场。然后本文研究了一些数值方法，例如有限元法和边界元法。首先，进行断裂实验和数值分析，并估算I型断裂韧性GIC。提出了一种实验与分析相结合的新方法。通过该方法，实验过程中无需测量裂纹长度。其次，提出了一种评估模式II断裂韧性的方法。在该方法中，需要估计上裂纹表面和下裂纹表面之间的接触面积以及它们之间的接触力分布。为此创建了新的 BEM 代码，它能够以良好的精度估计接触面积和力分布。通过在估计方案中引入该方法，可以轻松估计II型断裂韧性。最后提出了混合模态试件，并通过三维有限元分析检验了混合模态的状态。评估三维 J 积分并将其分解为三种应力强度因子模式：KI、KII 和 KIII。结果表明，该类试件虽然发生混合型断裂，但断裂模式以I型为主。结论是应考虑另一种包含模式 I、II 和 III 的方法。这个问题并没有引起广泛的关注，日本、美国和欧洲之间的一个新项目正在规划中。作为这个新项目的成员，我将继续努力建立一种新的方法来估计 CFRP 层压板的混合模式断裂韧性。

项目成果

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。”

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。”

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

Masanori Kikuchi, Takayuki Kobayashi, and Kazuro Kageyama: "MODE I INTERLAMINAR FRACTURE OF UNIDIRECTIONALLY REINFORCED CARBON/NYLON LAMINATES." Proc. of 6th Int. Congress of Experimental Mechanics, pp.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。”