ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2018, Vol. 39 ›› Issue (3): 221593-221593.

• Solid Mechanics and Vehicle Conceptual Design •

### Fastener connection flexibility of multi-bolted joint of composite laminate

HOU Chi, WAN Xiaopeng, HUANG Heyuan, NI Kaiqiang

1. School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China
• Received:2017-07-10 Revised:2017-12-20 Online:2018-03-15 Published:2017-12-20
• Supported by:
Aeronautical Science Foundation of China (20160953008)

Abstract: The connection flexibility of fasteners varies with the rows of bolts in a multi-bolted joint structure of composite laminates. To study the relationship between the fastener connection flexibility of multi-bolted joints and that of single-bolted joints, and develop the calculation method for predicting the fastener connection flexibility of multi-bolted joints, tensile tests of bolted joints of ZT7H/5429 composite laminates were conducted to calculate the fastener connection flexibility of the multi-bolted joint analytically. The influence of the bypass load on connection flexibility of fasteners was studied, and a formula for calculating the connection flexibility of fasteners accompanied with bypass loads was established. Considering that the value of the connection flexibility of fasteners correlates to the analysis model, model-adaptation functions were proposed to describe the flexibility deviation of the laminates between two bolts and utilized to develop the modeling-oriented formula for correcting the connection flexibility of fasteners. The proposed method was used to analyze the bolt load distribution of the ont-line five-bolt joint. The results show that with the proposed method, the maximum calculation error between the beam-shell model and the three-dimensional solid model can be reduced from 16% to 3%, and the calculation error of peak bolt load is reduced from 11% to 2%. The proposed modification method can help improve and realize accurate and fast calculation of bolt load distribution in the multi-bolted joint, and is especially applicable for the bolt group connection area of large-scale composite laminates.

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