Stiffness prediction method and load sharing mechanism of hybrid interference‐fit bolted‐bonded composite joint

Abstract

AbstractHybrid interference‐fit bolted‐bonded (HIBB) composite joint has a wide application prospect in improving bearing capacity of the hybrid structure. In order to deeply understand its load sharing mechanism, an analytical stiffness prediction model of HIBB composite joint was established, considering the influence of interference‐fit percentage, preload, friction coefficient, adhesive property, material performance, secondary bending moment and other parameters. Corresponding experiments were carried out to determine the experimental secondary bending moment coefficient, and the accuracy of the model was further verified. Research on HIBB composite joint shows that the hybrid form increases the adhesive failure displacement but has no effect on failure load. Before adhesive failure occurs, bolted joint stiffness is small and bolt load will increase suddenly to bear the load loss caused by the adhesive failure. It is further found that load‐sharing ratio of the bolt and total load of the structure increase with the increase of interference when adhesive failure occurs. Preload and friction coefficient have limited influence on total load of the structure at this moment, but have great influence on the bearing capacity of pure bolted structure after adhesive failure. The adhesive properties have great influence on the bearing capacity of bonded joint. Low modulus high strength adhesive can improve the load‐sharing ratio of bolt and enhance the bearing capacity by reducing the overall stiffness of the structure. Bearing mechanism of the two joint forms in the hybrid one was fully revealed, which provides a theoretical method for the application of HIBB composite joint.Highlights An analytical stiffness prediction model of HIBB composite joint was established to deeply understand its load sharing mechanism. Load sharing mechanism analysis and parametric research for the two joint forms were carried out and influences on stiffness were obtained. Low modulus high strength adhesive can improve the load‐sharing ratio of bolt by reducing the overall structure stiffness. Bearing mechanism of the two joint forms in the hybrid one was revealed.