Numerical Simulation Study on Cold Expansion of Metal- Composite Laminated Structures Bushings

With the increasing use of composites in aircraft and other aerospace vehicles, the fatigue strength of bolted connections between metals and composites has become increasingly critical. Cold expansion of bushings is widely employed to mitigate stress concentration around holes, thereby enhancing the fatigue life of materials. This study conducted a numerical simulation to compare and analyze the residual stress, equivalent plastic strain, and contact pressure around holes in metal-composite laminated structures after cold expansion using two types of bushings. The results demonstrated that, compared to single bushing, dual bushings generated greater residual compressive stress, equivalent plastic strain, and contact pressure at both the entry and exit sides of the laminated structure. Furthermore, dual bushings induced less expansion damage around the composite hole.