Shear performance of flexible and elastic composite lattice structures for application scenarios

Lattice structures possess high specific strength and lightweight characteristics, making them ideal as filling frameworks for tissue engineering scaffolds. This study examines the shear performance and interaction mechanisms of composite lattice structures under shear loading through both experimental and numerical simulations. It investigates the relationship between the rod diameter parameters of composite lattice structures and their shear performance, as well as their responses to interaction effects. The experimental analyses focused on the damage processes and failure modes of the matrix body-centered cube (BCC) structure. Numerical simulations revealed the stress distribution within composite joints, enabling an analysis of the structures’ fracture modes based on these distributions. A multicriteria evaluation system was developed to comprehensively assess composite lattice structures for soft joint application scenarios. Utilizing the selected structure for soft joint tissue applications, corner optimization was performed, resulting in customized designs for filling-type tissue engineering scaffolds derived from the optimization outcomes. Experimental results demonstrate that with a rod diameter of 0.45 mm, the ultimate shear strength of FCC-BCC and SC-BCC increases by 159% and 80%, respectively, compared to the matrix alone. After optimization, stress concentrations at the joints are effectively minimized. Furthermore, when the structure is bent 90° on one side, the interlayer force does not exceed the shear force of the small joint capsule ligament. The proposed design approach offers a robust framework for applying flexible lattice scaffolds in diverse scenarios.