This study establishes an assembly model for composite/aluminum alloy multi-bolt joint structures and investigates the preload distribution patterns of the bolts under four tightening sequences: Sequential tightening

staggered tightening

tightening from the middle to the ends

and tightening from the ends to the middle. It focuses on three assembly conditions: No assembly gap

forced assembly with a gap

and gap compensation with shims. By combining experimental and finite element methods

the preload distribution patterns under the aforementioned tightening sequences were analyzed. The results show that in cases involving an assembly gap

the bolt preload variation increases as the assembly gap expands. Among the four tightening sequences

when adopting the sequence of tightening from the ends to the middle

the preload distribution exhibits better consistency

and the final preload of each bolt is closer to the target preload.