Failure mechanism study of multi-hierarchy pre-tightening tooth connection based on an optimization-driven design approach

Abstract

The bio-inspired multi-hierarchy fractal design of composite Pre-Tightening Tooth Connections (PTTC) offers significant potential to enhance their load-bearing capacity. However, the failure mechanisms of multi-hierarchy PTTC structures remain inadequately explored, and the involvement of numerous interrelated geometric parameters renders the engineering design process highly complex. To address these challenges, this study conducts a comprehensive analysis of the failure behavior and load transfer mechanisms in multi-hierarchy PTTC joints through an optimization-based design methodology. A systematic optimization framework is first proposed to evaluate joint strength under various geometric parameter combinations, establishing a mathematical correlation between sub-tooth geometry and joint bearing performance. Subsequently, a progressive damage model is employed to visualize the damage evolution within the joint. Finally, experimental investigations are carried out to validate the influence of sub-tooth geometry on the mechanical performance of the connection. The results demonstrate that the multi-hierarchy PTTC configuration effectively distributes local stress concentrations and delays the onset of failure along the primary shear plane by establishing multi-hierarchy load transfer paths. Moreover, the spatially decoupled distribution of secondary shear planes formed by sub-teeth contributes to further stress relief, thereby improving the overall structural integrity and load-bearing efficiency of the connection.