TPMS-based mechanical bonding structures optimized by FEM with periodic boundary conditions

Mechanical Bonding Structures (MBS) provide a reliable alternative to chemical bonding for joining dissimilar materials, enhancing mechanical performance and broadening design flexibility. This study introduces a novel approach to optimizing Triply Periodic Minimal Surfaces (TPMS)-based MBS using the Finite Element Method (FEM) with Periodic Boundary Conditions (PBC). A hybrid TPMS-based representation is proposed, enabling topological and geometric variation to improve mechanical bonding performance. To address the challenges of non-periodic mesh and partial periodicity in FEA, a new PBC tool is developed, ensuring accurate numerical modeling of MBS. A data-driven optimization framework, incorporating Bayesian optimization, is applied to maximize the tensile strength of TPMS-based MBS. The proposed method is validated through mechanical tests on dual-material specimens fabricated via various manufacturing processes. Results demonstrate up to 109.5% improvement in tensile strength across different material combinations, confirming the effectiveness of the optimization strategy. This work provides a generalizable approach for designing high-performance MBS in multi-material manufacturing.