A Multi-Cell Hybrid Approach to Elevate the Energy Absorption of Micro-Lattice Materials.

Lijun Xiao,Xiao Xu,Weidong Song,Menglei Hu

doi:10.3390/ma13184083

Abstract

Multi-cell hybrid micro-lattice materials, in which the stretching dominated octet cells were adopted as the strengthen phase while the bending dominated body centered cubic (BCC) lattice was chosen as the soft matrix, were proposed to achieve superior mechanical properties and energy absorption performance. Both stochastic and symmetric distribution of octet cells in the BCC lattice were considered. The cell assembly micromechanics finite element model (FEM) was built and validated by the experimental results. Accordingly, virtual tests were conducted to reveal the stress–strain relationship and deformation patterns of the hybrid lattice specimens. Meanwhile, the influence of reinforcement volume fraction and strut material on the energy absorption ability of the specimens was analyzed. It was concluded that the reinforced octet cells could be adopted to elevate the elastic modulus and collapse strength of the pure BCC micro-lattice material. The multi-cell design could lead to strain hardening in the plateau stress region which resulted in higher plateau stresses and energy absorption capacities. Besides, the symmetric distribution of reinforcements would cause significant stress fluctuations in the plateau region. The obtained results demonstrated that the multi-cell hybrid lattice architectures could be applied to tailor the mechanical behavior and plastic energy absorption performance of micro-lattice materials.

Highlights

Micro-lattice materials have attracted much attention due to their excellent mechanical properties, such as ultra-high specific stiffness and strength, outstanding vibration isolation performance and energy absorption capacities [1,2,3]
The numerical results demonstrate that the reinforcement of octet cells can be adopted to elevate the elastic modulus of the pure body centered cubic (BCC) lattice
Motivated by the dual-phase metallic materials and composites, the stretching dominated octet cells and bending dominated BCC cells are mixed to composites, the stretching dominated octet cells and bending dominated BCC cells are mixed to improve the energy absorption performance of the pure BCC micro-lattice material

Summary

Introduction

Micro-lattice materials have attracted much attention due to their excellent mechanical properties, such as ultra-high specific stiffness and strength, outstanding vibration isolation performance and energy absorption capacities [1,2,3]. Different from the other lightweight cellular materials such as foams, whose microstructure is random and can hardly be designed to regulate the macroscopic properties, the micro-lattice materials are with periodic unit cells and the corresponding mechanical behavior can be tuned by the microscopic features. With the rapid development of additive manufacturing, it becomes more convenient to precisely tailor the mesoscale parameters of micro-lattice materials for achieving better mechanical properties, such as higher modulus/strength and energy absorption [4,5,6]. The macroscopic mechanical performance of micro-lattice materials is closely related to their microscopic cell architectures. Ashby [2] systematically analyzed the effect of the two deformation mechanisms on the stress-strain response of cellular

Methods

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Discussion

Conclusion