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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2021, Vol. 42 ›› Issue (5): 524306-524306.doi: 10.7527/S1000-6893.2020.24306

• Article • Previous Articles     Next Articles

Fatigue life prediction method for hybrid multi-bolted joints based on damage weight

ZHANG Junrui1,2, ZHENG Xitao1,2, YUAN Lin1,2, ZHONG Guiyong3, LI Guochen3   

  1. 1. School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China;
    2. Institute of Aircraft Composite Structures, Northwestern Polytechnical University, Xi'an 710072, China;
    3. AVIC Chengdu Aircraft Design & Research Institute, Chengdu 610041, China
  • Received:2020-05-28 Revised:2020-08-31 Online:2021-05-15 Published:2020-09-24

Abstract: The composite and metal material hybrid multi-bolted joints are the most common connection form in contemporary aircraft structures. Research on the fatigue performance of the hybrid multi-bolted joints helps to improve the understanding of the aircraft structure fatigue damage. A numerical analysis and an experimental study on the multi-nail connection structure of the ZT7H/QY9611 carbon fiber reinforced resin matrix composite plate and the 30CrMnSiNi2A metal plate with Ti-6Al-4V titanium alloy as bolts are conducted. The finite element method is used to predict the fatigue damage of the composite materials and fasteners, respectively, and simulate the damage near the nail holes on the composite material plate. An empirical formula with the distribution of fasteners and the number of layers of the composite material plate as parameters is proposed to accurately estimate the damage weight of the composite materials and fasteners, thereby effectively improving the accuracy of fatigue life prediction of hybrid multi-bolted joint structures. Through categorization and discussion of the damage patterns of nail holes based on the experimental results, the damage evolution of hybrid multi-nail connectors is explored; C-scan technology is adopted to detect layered damage of the composite materials which is compared with the simulation results to further verify the model. Compared with the experiment value, the logarithmic error of the life prediction simulation value considering the damage weight is only 1.1%, which is a significant increase from 8.4% of the method without considering the damage weight.

Key words: composite materials, multi-bolted joints, fatigue damage simulation, fatigue life prediction, layered damage detection

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