Biomimicry and topology optimization for adhesive toughness design inbonded heterogeneous films

Heterogeneous films have recently been extensively studied due to their superior material properties comparedto homogeneous films. However, studies focusing on the design of heterogeneous films, especially withmulti-material phases and structures, have been relatively scarce. This paper presents a bioinspired designmethodology aimed at optimizing the mechanical properties of heterogeneous films through the strategicarrangement of stiff and soft material blocks. The heterogeneous film is represented as a composite beamand the interfacial failure process is simulated by a cohesive zone model. Then an optimization algorithmis employed to adjust the distribution of stiff materials within the soft film patch in the heterogeneous film.The results show that a nearly twofold increase in adhesive toughness for the optimized film compared tothe original. Further discussions shed light on the energy distribution and variations in the fracture processzone size, providing insights into the observed enhancements. In terms of efficiency, the proposed optimizationmethod distinctly outperforms the greedy method, demonstrating the potential for a more effective and efficientdesign of heterogeneous films with improved mechanical properties.