Abstract: In this paper, the strength and damage process of composite thin plate bolted joint structures under tensile loading are investigated by experimental and simulation analysis. Firstly, the basic performance parameters of the composites were obtained by standard mechanical tests, and then tests were carried out on thin-plate composite joints with varying bolt preloads, different layup configurations, and both single and double bolt distributions. Based on the stiffness continuous degradation model and the three-dimensional Hashin failure criterion, the bolt preload was reverse-calculated by testing the friction between the overlap plates, and the preload of the bolt was simulated using an equivalent cooling method. Calibration of the open-hole plate was performed through both experiments and simulations, leading to the development of a three-dimensional finite element model of the bolted composite laminate. Finally, a progressive failure analysis was conducted to understand the strength and damage mechanisms of the composite plate joints. The results indicated that: with the increase of bolt preload, the peak load of the thin plate composite joint increases and the fracture displacement decreases; the damage process of the thin plate composite joints with different layups is related to the proportion of their layups; the ultimate load of transverse double-bolt joints is approximately twice as much as that of the single-bolt joints, and the ultimate limit of longitudinal double-bolt joints is slightly lower.

Key words: thin plate composites, bolted joint, progressive failure, damage process