Strain Rate Effect on Dynamic Responses of Lattice Structures

Abstract

Due to excellent energy absorption performance, lattice structures have great potential for industrial application scenarios such as impact protection devices, biomedical and aerospace industries. Some studies have demonstrated that, compared to quasi-static strength, inertia effect would enhance the strength of lattice structures under impact. At the same time, strain rate sensitivity of parent material is another possible contribution. However, few quantitative analyses have been conducted to clarify their contributions associated with loading velocity. Therefore, this paper is to quantitatively study their contributions in detail. BCC lattice structures were employed, and some samples were printed using 316L stainless steel. Strain rate effect on the impact response of lattice structures is to be investigated in detail. Quasi-static and dynamic impact experiments were carried out, followed by finite element (FE) simulations based on the Johnson-Cook (J-C) hardening model. Strain rate effect of the parent material on the dynamic compressive plateau stress of the lattice structures was quantitatively examined. Subsequently, an analytical model based on the shock theory which considering strain rate effect was proposed. The analytical model was validated using FE and experimental results, which is able to predict the dynamic impact performance of lattice structures.

Keywords: additive manufacturing, Lattice structure, Dynamic response, strain rate effect, Inertia effect