Journal of Shanghai Jiao Tong University ›› 2021, Vol. 55 ›› Issue (11): 1459-1466.doi: 10.16183/j.cnki.jsjtu.2020.360

Special Issue: 《上海交通大学学报》2021年12期专题汇总专辑 《上海交通大学学报》2021年“材料科学”专题

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Fitting Model to Compressive Strength of Composite Laminate After Impact

GUAN Qingyu1,2, XIA Pinqi1(), ZHENG Xiaoling3, WU Guanghui4   

  1. 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:2020-11-06 Online:2021-11-28 Published:2021-12-03
  • Contact: XIA Pinqi E-mail:xiapq@nuaa.edu.cn

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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