Failure mode analysis of stiffness-guided lattice structures under quasi-static and dynamic compressions

The stiffness and failure properties of the materials are a pair of opposing physical quantities, which are often mutually constrained and fettered. Therefore, it is extraordinary meaningful and essential to explore the failure behavior of the lightweight porous materials under the design strategy of the optimal stiffness. In this paper, the failure modes of a stiffness-guided lattice specimen, which is designed by the topology optimization method and manufactured by the 3D printing technique, are investigated under quasi-static and dynamic compressions. The results illustrate that the failure behavior of the stiffness-guided lattices is strongly dependent on the non-optimized structural parameter and the loading strain-rates when the base material for 3D printing is polyamide 12 (PA12). The failure modes are mainly manifested as three categories: the unstable collapse mode, the bending collapse mode and the brittle collapse mode. In addition, the Young's modulus, initial crushing stress, and energy absorption behavior of the stiffness-guided lattices have been studied. The results indicate that the lattices' crush behavior and energy absorption behavior are highly dependent on the failure modes. Remarkably, the stiffness-guided lattices exhibit superior specific energy absorption, stable deformation mode, and a high compressive modulus in the bending collapse mode.

Automated summary

The study investigates the failure behavior of stiffness-guided lattice structures under different failure modes, revealing a close relationship between failure behavior, structural parameters, and loading strain rates. The failure modes primarily include unstable collapse, bending collapse, and brittle collapse, which are crucial in the design of lightweight porous materials.