), 郑晓玲3, 吴光辉4 1.南京航空航天大学 航空学院, 南京 210016
2.中国商飞上海飞机设计研究院 复合材料中心, 上海 201210
3.中国商飞上海飞机设计研究院, 上海 201210
4.中国商用飞机有限责任公司, 上海 200126
收稿日期:2020-11-06出版日期:2021-11-28发布日期:2021-12-03通讯作者:夏品奇E-mail:xiapq@nuaa.edu.cn作者简介:管清宇(1988-),男,上海市人,博士生,高级工程师,现主要从事复合材料结构损伤容限研究.Fitting Model to Compressive Strength of Composite Laminate After Impact
GUAN Qingyu1,2, XIA Pinqi1(), ZHENG Xiaoling3, WU Guanghui4 1. College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
2. Composite Center, COMAC Shanghai Aircraft Design and Research Institute, Shanghai 201210, China
3. COMAC Shanghai Aircraft Design and Research Institute, Shanghai 201210, China
4. Commercial Aircraft Corporation of China, Ltd., Shanghai 200126, China
Received:2020-11-06Online:2021-11-28Published:2021-12-03Contact:XIA Pinqi E-mail:xiapq@nuaa.edu.cn摘要/Abstract
摘要： 碳纤维增强的环氧树脂复合材料广泛地应用于飞机的主要承力结构,其冲击后压缩强度是损伤容限评估的重要内容.目前工程上主要利用大量试验获取冲击后压缩强度,对此需要开发一套简便的数学模型以描述冲击后压缩强度规律.提出一种全新的用于拟合复合材料层压板冲击后压缩强度数据的数学模型.采用该模型和初始模型参数,可以将不同冲击能量下的冲击后压缩强度数据转化为某一等效无损伤压缩强度数据,进而采用极大似然估计法对其进行正态分布拟合,得到正态分布的标准差.重复以上步骤,直至获得标准差的极小值,即可确定冲击后压缩强度数据拟合模型参数的最佳估计值.为了进一步表明该模型的适用性,进行不同厚度、铺层比例和材料类型的冲击后压缩试验,并采用该模型拟合试验数据.结果表明该模型对不同厚度、铺层比例和材料类型的冲击后压缩试验数据均具有较好的适用性.
关键词: 复合材料, 层压板, 冲击损伤, 压缩强度, 拟合模型, 极大似然估计
Abstract: Carbon fiber-reinforced epoxy composites are widely used in the primary structure of aircraft, the compressive strength of which after impact is an important part in the evaluation of damage tolerance. At present, it mainly relies on a large number of tests to obtain compressive strength after impact in the engineering project. Therefore, it is necessary to develop a simple mathematical model to describe the compressive strength law after impact. A novel mathematical model for fitting compressive strength data of composite laminate after impact was proposed. Using the mathematical model and the initial model parameters, the compressive strength data after impact at different impact energy could be converted into some equivalent undamaged compressive strength data. Then, these equivalent undamaged compressive strength data were normally fitted using the maximum-likelihood estimate (MLE) method to obtain the standard deviation of normal distribution. The above steps was repeated until the minimum estimator of standard deviation was obtained. Hence, the best estimators of parameters for the mathematical model were determined. In order to further demonstrate the applicability of the mathematical model, post-impact compressive strength tests including different thicknesses, layup proportion, and material types were conducted, and the experimental data were fitted with the model. The results indicate that the mathematical model has a good applicability to the compressive strength test data after impact including different thicknesses, layup proportions, and material types.
Key words: composite, laminate, impact damage, compressive strength, fitting model, maximum-likelihood estimate (MLE)
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